Textile and leather review 4 2020

TEXTILE & REVIEW LEATHER

4/2020 Volume 3 Issue 4 2020 textile-leather.com ISSN 2623-6257 (Print) ISSN 2623-6281 (Online)

TEXTILE & REVIEW LEATHER Editor-in-Chief

Dragana Kopitar, University of Zagreb Faculty of Textile Technology, Croatia

Assistant Editor

Ivana Schwarz, University of Zagreb Faculty of Textile Technology, Croatia

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Editorial Advisory Board

Shahid Adeel, Government College University Faisalabad, Department of Chemistry, Pakistan Emriye Perrin Akçakoca Kumbasar, Ege University, Faculty of Engineering, Turkey Tuba Bedez Üte, Ege University, Faculty of Engineering, Turkey Mirela Blaga, Gheorghe Asachi Technical University of Iasi, Faculty of Textiles, Leather and Industrial Management, Romania Patrizia Calefato, University of Bari Aldo Moro, Department of Political Sciences, Italy Andrej Demšar, University of Ljubljana, Faculty of Natural Sciences and Engineering, Slovenia Krste Dimitrovski, University of Ljubljana, Faculty of Natural Sciences and Engineering, Slovenia Ante Gavranović, Economic Analyst, Croatia Ana Marija Grancarić, University of Zagreb, Faculty of Textile Technology, Croatia Huseyin Kadoglu, Ege University, Faculty of Engineering, Turkey Fatma Kalaoglu, Istanbul Technical University, Faculty of Textile Technologies and Design, Turkey Hüseyin Ata Karavana, Ege University, Faculty of Engineering, Turkey Ilda Kazani, Polytechnic University of Tirana, Department of Textile and Fashion, Albania Vladan Končar, Gemtex – Textile Research Laboratory, Ensait, France Stana Kovačević, University of Zagreb, Faculty of Textile Technology, Croatia Aura Mihai, Gheorghe Asachi Technical University of Iasi, Faculty of Textiles, Leather and Industrial Management, Romania Jacek Mlynarek, CTT Group – Textiles, Geosynthetics & Flexibles Materials, Canada Abhijit Mujumdar, Indian Institute of Technology Delhi, India Monika Rom, University of Bielsko-Biala, Institute of Textile Engineering and Polymer Materials, Poland Venkatasubramanian Sivakumar – CSIR – Central Leather Research Institute, Chemical Engineering Department, India Pavla Těšinová, Technical university of Liberec, Faculty of Textile Engineering, Czech Republic Savvas Vassiliadis, Piraeus University of Applied Sciences, Department of Electronics Engineering, Greece

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Jelena Grbavec, Croatia

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Marina Sertić, Seniko studio Ltd., Croatia

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Textile & Leather Review ‒ ISSN 2623-6257 (Print), ISSN 2623-6281 (Online) UDC 677+675 DOI: https://doi.org/10.31881/TLR Frequency: 4 Times/Year The annual subscription (4 issues). Printed in 300 copies Published by Seniko studio d.o.o., Zagreb, Croatia Full-text available in open access at www.textile-leather.com

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TEXTILE & LEATHER REVIEW ISSN 2623-6257 (Print)

ISSN 2623-6281 (Online) CROATIA

VOLUME 3

ISSUE 4

2020

p. 181-244

CONTENT SCIENTIFIC REVIEW 186-201

Camouflage Fabric - Fabric for Todayâ&#x20AC;&#x2122;s Competitive Era Madan Lal Regar, Akhtarul Islam Amjad, Atiki Singhal

ORIGINAL SCIENTIFIC ARTICLE 202-212

Characterization of Sisal/Polypropylene Composites Treated with Plasma Ba Muralidhar

213-225

Enzyme-Accelerated Acid Hydrolysis of Untanned Proteinaceous Wastes from Tanning Industry Md. Nur-E-Alam, Nasifa Akter, Kanish Fatema, Md. Abul Kashem Azad, Shimul Chakma, Md. Anwar Arfien Khan

226-239

Study on Comparative Analysis of Basic Woven Fabrics Produced in Air-Jet Loom and Determining Structure for Optimum Mechanical Properties and Production Md. Nurunnabi, Jubayer Ibn Haris, Fairooz Raisa Mridula

Ferenc Vasadi Âˇ + 36 (0)30 94 69 123 ferenc.vasadi@soliver-shoes.com shoe.com GmbH & Co. KG Âˇ soliver-shoes.com Member of the Wortmann Group

REGAR ML, et al. Camouflage Fabric - Fabric for Today’s Competitive Era… TLR 3 (4) 2020 186-201.

Camouflage Fabric - Fabric for Today’s Competitive Era Madan Lal REGAR1*, Akhtarul Islam AMJAD2, Atiki SINGHAL3 Department of Fashion Design, National Institute of Fashion Technology, Jodhpur, 342001 India Department of Textile Engineering, Uttar Pradesh Textile Technology Institute, Kanpur, 208001 India 3 Department of Textile Technology, Uttar Pradesh Textile Technology Institute, Kanpur, 208001 India *madan.uptti@gmail.com 1 2

Scientific review UDC 677-488:623.77 DOI: 10.31881/TLR.2020.10 Received 16 Jun 2020; Accepted 28 Aug 2020; Published Online 11 Sep 2020; Published 1 Dec 2020

ABSTRACT Innovation is the foremost requirement of today’s competitive era. Innovation refers to improving on an existing concept or idea using a stepwise process to create a commercially viable product. Food, clothing, and shelter are the basic needs of a human being. Clothing is made from textiles; with the help of textiles, the shelters are made more comfortable and attractive. Traditionally, fabrics are used for apparel and home furnishing purpose, but these days, application is diversifying in order to satisfy technical and protective functions. Camouflage fabrics are the ones most suitable for technical and protective purposes. Over the past few years, researchers have put emphasis on the development of camouflage fabrics for security measures for troops, and for activities intended to hide facts and mislead the enemy. Years of investigations have been invested into innovation in the manufacture of these fabrics which are providing the ultimate performance and reliability. In this review paper, an attempt is made to comprise principle, manufacturing techniques, properties and application. This paper also highlights the modern development and recent trends in the field of camouflage fabric. Camouflage and multispectral universal camouflage are the main areas of recent trends on camouflage fabrics. Camouflage fabrics are mostly used for hunting, survival prepper, tactical and military protective wears. KEYWORDS Camouflage fabric, Textile, Protective wear, Electrochromic fabrics

INTRODUCTION The word camouflage is derived from the French word “camoufler” which means to disguise or hide from something. The phrase, which can provide the clear-cut definition, is: the tool used for breaking up the recognizable human form. Plants and animals show natural camouflage. A chameleon lizard changes its colour according to the surroundings and the leaves of Corydalis hemidicentra plant match the colour of the rocks [1]. Artificial camouflage can be obtained for concealing the personnel or the equipment from enemies. Textiles are playing the key role in generating artificial camouflage effects. Defence is the main sector which utilizes artificial camouflage produced by fabrics. Nowadays, most of the countries disburse a huge amount of their revenue, about 2 to 3 percent of the total defence budget, over the defence including vehicles, bombs, missiles and, most importantly, the attire of the personnel [2]. The main aim of camouflage is to help to hide the vehicles, the equipment and the personnel from the enemy to reduce the number of attacks from the enemy. Moreover, it might become difficult for the enemy to spot the vehicle and the 186 www.textile-leather.com

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personnel. Camouflage fabrics were first used during the Second World War. A tremendous increase in use was seen after the war in Iraq in 1991 [3]. Several researches are going on to improve quality with lesser cost. The procedure for making a natureraised fabric with eight layers is a recent development in the field of camouflage fabric, which is used for a special function called hunting research. The major manufacturers of the camouflage fabric are South Korea, China, Brazil, Indonesia and Turkey. Camouflage fabrics are used by most of the armed forces including army, navy, air force and para-military forces. It is estimated that more than 350 million meters of fabric is consumed worldwide annually. Camouflage fabric is produced in different patterns across the world. Russia uses a woodland type of pattern, Germany uses Flecktarn or a mottled camouflage type of pattern and the United State Air Force uses a digital tiger-stripe type of pattern.

PRINCIPLES OF CAMOUFLAGE: The principle refers to the idea or the concept out of which this camouflage came into existence. The camouflage fabric works on six principles [4-5].

Resemblance to the Surroundings Many animals and plants change their colour according to the surroundings, e.g. chameleon lizards or a plant named Corydalis hemidicentra. Thus, fabrics can be prepared in a way which makes them resemble the surroundings, thus making it more difficult to be spotted by the enemy [6].

Disruptive Colouration The location and identity may be concealed through a colouration pattern which causes visual disruption because the pattern does not coincide with the shape and outline of the vehicles or the equipment [7].

Motion Dazzle A pattern of contrasting stripes that degrade an observer’s ability to judge the speed and direction of a moving object. This concept (Figure 1a) was used during the Second World War, when ships were painted to reduce the attacks from the submarines [8-9]. Counter Shading It creates an illusion of flatness. In this, the upper part of the vehicle is painted in the darkest tone of colour and the lower part with a light colour, making the counter-shaded vehicle nearly invisible against a suitable background [10].

Mimicry Principle The mimicry principle tries to adapt not only the colour but also shape of the environment. The toad (Figure 1b) not only matches the colour of the leaves but also acquires the same shape as that of the leaves and becomes difficult to be identified by the enemy.

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(a)

(b)

Figure 1. (a) Motion dazzle principle; (b) Toad between the leaves [3,9]

Continuation of the Pattern Continuation of the pattern suggests that the personnel, vehicle, or equipment should be camouflaged in such a way that it appears in the continuation of the surrounding pattern or structure. The spider over the rocks is in continuation of the pattern made up by the rocks (Figure 2). Thus, it becomes difficult to be spotted by the enemy.

Figure 2. Continuation of the pattern of the rocks and a soldier difficult to spot in the forest [3]

REQUIREMENTS FOR MANUFACTURING THE CAMOUFLAGE FABRIC For manufacturing the camouflage fabric there are two main substances: colour type and fabric type. Both organic and inorganic substances can be used to produce the camouflage fabric [2, 11]. Materials required for the preparation of camouflage fabric are as follows:

Colour Requirements • Special or selected dyes like Procion MX and pigments like barium sulphate. • Infrared absorbing pigment including both organic and inorganic materials, such as perylene black, phthalocyanine blue and organic materials includes ferric oxide, lead chromate, chromium oxide and isoindoline. These materials are incorporated into the printing paste. • There are some infrared absorbing pigments which are incorporated into the polymer in the fibre forming process, such as carbon black. • Infrared reflectance coatings, such as carbon compound coated over the synthetic fibres.

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Fabric Requirements • The prepared camouflage fabric should meet certain requirements before it is used for the defence purpose or any other application. The synopses of these properties are given below [11]: • The fabric should possess high pilling resistance and should not generate the burr and snag. • Tensile and tearing strength should be high, it may vary according to the end use application. • Fastness regarding light, wash and perspiration should be good. • The fabrics should possess the special functional properties, such as being flame retardant, waterproof, wind-proof, breathable and having antimicrobial properties. • The fabric should be non-glaring.

MECHANISM FOR MANUFACTURING CAMOUFLAGE FABRIC • The various properties of the camouflage fabric are described below with a brief description. These properties are listed as follows [12]: • By changing the pH • By changing the oxidation state • By changing the bond arrangement • By mechanochromism • Due to the magnetic field

pH Change Molecules can change colour dramatically in the presence of acids and bases as the camouflage fabric is dipped into solvents of different polarity. Change in the polarity causes the change in the colour.

Bond Breaking There are a number of systems that undergo reversible bond breaking and bond forming processes that result in dramatic colour change. For example: enol is colourless but on rearrangement of atoms it showed orange colour for the cis form, whereas for the transform it showed the red colour.

Oxidation State Change Due to change in the oxidation state the colour of the fabric changes. For example: copper shows different oxidation state, such as 0, +1 and +2. With different oxidation states, different colours are observed, such as in 0-oxidation state as the molecules of the fabric are rearranged within the fabric structure the orange colour of the fabric is observed, while in the +1-oxidation state, the green colour is observed and in the +2-oxidation state, the blue colour. Moreover, migration of ions also leads to the change in oxidation state, thus colour is changed.

Mechanochromism It basically works on the principle of sensing receptors. Sensing receptors sense the strain applied over the fabric and then change the colour of the fabric. For instance: green colour fabric when stretched alters the colour and finally becomes orange in colour.

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Magnetic Field Effect The colour of the fabric changes in the presence of a magnetic field. For example: if colour of the solution is red and when the magnet is pushed closer to the solution step by step, we can observe the colour changes, and the solution attains the blue colour when the magnet is in close vicinity of the solution.

CHROMIC MATERIALS AND MANUFACTURING TECHNIQUES Chromic materials are also known as camouflage fibres, because they have the ability to change their colour according to external situations. Chromic materials are used to make the camouflage or colour changing fabrics. These materials are either applied in coating form or incorporated into the polymer structure. Chromic materials are classified on the basis of different external stimuli [13]. These materials are listed below: • Photochromic: the external stimulus is the light • Electrochromic: the external stimulus is the electricity • Thermochromic: the external stimulus is the heat • Solvatochromic: the external stimulus is a solvent • Piezochromic: the external stimulus is the pressure • Carsolchromic: the external stimulus is an electron beam

Photochromic Technique Photochromism is a phenomenon in which the light as an external stimulus is used to facilitate changes in the molecular structure of a single chemical species without changing the molecular weight and reversibly produce two isomers with different colours (absorption spectra) [14]. This phenomenon is rarely used in textile applications. The main utilization of this technique is in the imaging system. Photochromic dyes can be classified into two types from the viewpoint of thermal stability namely, • T-type • P-type The general behaviour of P-type and T-type photochromic dyes are depicted in Figure 3.

Figure 3. General behaviours of most commercial T-type and P-type photochromic colourants [15]

T-type For the T-type dyes, the conversion process is driven by heat. The back reaction is caused thermally, although for commercial photochromic classes, visible light may also contribute. The rate of thermal fading is often expressed as “half-life” which is the time taken for absorbance to halve, once the activating light has been removed. For ophthalmic utility, a short half-life is desirable to stop vision being impaired when there is a sudden drop in light intensity [16]. Azobenzene, spirooxazines, naphthopyrans and spiropyran are the families of dyes that have had the greatest commercial and industrial importance. Such types of dyes are used in nail varnishes, which acquire colour in the sun, as well as in various other cosmetics and personal care products. This type of dye is used as a functional material, for example, in anti-counterfeit marking 190 www.textile-leather.com

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on bank notes, security printing such as passports where light responsive marks are marked as indicators of genuineness. Arresting photochromic effects can also be developed by incorporation of dyes into thermoplastics materials. Spirooxazines and naphthopyrans are used in mass colouration of polyethylene and polypropylene that have relatively low glass transition temperatures with flexible chains. That gives striking colour changes at inclusion levels of 0.3%w/w and less. Screen printing microencapsulated colourant is the most effective method of applying photochromic dyes because typical high crystalline polymers, such as polyester, hinder photochromism, while exhaustion dyeing technique tends to damage dyes. Photochromic effect can be incorporated to garments through the use of polypropylene thread that has been melt-spun with photochromic dye [14-16]. The general lack of robustness of T-type photochromic dyes prevents it from being used in particularly demanding applications where controlled switching between one or more states (coloured and/or colourless) is demanded [17].

P-type For the P-type photochromic dyes, the process is driven by light irradiation and is not affected by the heat, remaining so until switched back by other wavelengths. A significant research both in academia and industry has been done in P-type photochromic dyes because of their potential as molecular switches [18]. However, much time, effort and money has been spent on developing P-type applications, yet it cannot be really commercially viable. Diarylethenes and fulgides are the families of dyes that have been investigated most in this connection. Fulgides are used in conventional colouration areas such as textiles and printing inks [19]. Diarylethenes offer a wide opportunity for the design of molecules whose optical characteristics can be switched in a controlled manner between persistent states. Great efforts have been made in P-type photochromic systems which stems from their potential use as functional colourants within the fields of optoelectronics, data storage, and nanotechnology [14]. Nanotechnology is a novel avenue because of its solid phase photochromism. In this context crystals of dihetarylethenes experience changes in shape, as well as colour, which results in molecular geometry variation during photochromic transitions. Such variation in particle dimensions forms the basis for light-driven actuators in nanomachinery. Molecules that switch optically are also utilized in the field of information technology because they could deliver memory systems with higher densities than those of current available commercial devices [19-20].

Thermochromic Technique The word thermochromic is the combination of two words: thermos and chromic, where thermos means heat and chromic means colour change. When the chromic materials change colour due to the application of heat such type of fabrics are called thermochromic fabrics [21]. This phenomenon is referred to as thermochromism. For example, if we heat an iron bar in a furnace then it changes colour gradually from its black colour to red and then finally to yellow colour. This is because, as heat is supplied, atoms get excited and move to a higher state and then, to attain the stable state again, they emit light and thus it appears as if the colour is changed [22]. Nowadays, lens used on a sunny day provide protection to eyes but when exposed to cold weather they act as ski-googles. Moreover, thermochromic prints are also used on the fabric, which changes colour when heat or temperature is changed. The printed colour pattern (classic green and brown camouflage) mimics jungle motif design which transforms to desert colour motif on application of heat from external sources. Since thermochromic systems involve intramolecular transformations, it means that a large amount of energy is required to change the www.textile-leather.com 191

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colour. Thermochromic (TC) glazing (Pleotint, Ravenbrick, Solarsmart, etc.) can automatically modify its optical characteristics with respect to the external surface temperature, which governs a solar smart-phase transition or chemical reaction between two different states. The material looks transparent when the temperatures is lower than the transition value and looks opaque at higher temperatures. The transition temperature range remains between 10 °C (maximum transparency) and 65 °C (minimum transparency). A wide range of organic and inorganic compounds in films of metal oxides, such as vanadium oxide, show the characteristics of thermochromism. These chromic materials are applied in two ways: [23-24] • By using the leucodyes • By using liquid crystal substances called cholesteric or chiral nematic systems. In this system the molecules form helices. In both the cases the dyes are entrapped in microcapsules and are applied to the fabric like pigment in resin binder. Molecular rearrangements are done to change the colour of the fabric when the arrangement of the molecules is altered (e.g. spiro lactone).

Figure 4. (a) Hyper colour shirt, (b-c) Thermochromism principle [23-26]

Using leucodyes These are organic carbon-based dyes or chemicals. As the leuco form changes to non-leuco form, its reflection and absorption rate changes. Thus, different colours are observed. Leucodyes can be used in thermal computer printed paper and in hyper colour T-shirts which change colour on touch. Leucodyes are simply applied with the any of the printing method, generally with the screen-printing [22].

Using liquid crystals Liquid crystals are not purely solid but somewhat in liquid state. This phase is also called as nematic or sematic phase because molecules are roughly arranged. These are spherical capsules of smaller diameter than that of hair. There are two methods in which we can apply liquid crystals which are as follows: 1. By using liquid crystal capsules which can be incorporated into fibres by spinning technique. As they are locked into polymer fibres, fabric will not lose the colour on washing. 2. By coating the liquid crystal capsule over the fabric, which can be done either by direct spraying or by printing over the fabric. When the nematic material is presented against a black background its impact gets maximized. An example is the fabric used in medicine to detect arteries and veins – such type of fabric is prepared by spraying the capsules over the black bandage [22, 28-29].

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Figure 5. Effect of distance between liquid crystals layer on colour [29-31]

The effect of distance between liquid crystal layer is shown in Figure 5. The different medium has different reflection of light. It is observed from the Figure 5 that if one liquid crystal is used then there is narrow temperature range, but if we use multiple crystals the temperature range can be widened. The colour which is reflected by liquid crystal depends on the closeness of the crystals together.

Electrochromic Technique When chromic materials change colour of the fabric due to the application of electricity or voltage such type of fabrics are called electrochromic fabrics [26]. This phenomenon is referred to as electrochromism. Electrochromism may also be defined as when a material is electrochemically oxidized, the reversible change in optical properties occurs. The colour change between a transparent or bleached state and coloured state or between two coloured states is thus displayed by such type of materials. However, the working definition of electrochromism has now been extended to include devices for modulation of radiation so that ‘colour’ means response not only by the human eye but also by the detectors at different wavelengths like near infrared, thermal infrared and microwave radiation. Electrochromic principle is used in glass windows of buildings, for anti-glare car windows, for sun-roof and rear vision mirrors [26-27]. There are three types of materials: • Type1 - materials which in both oxidized and reduced form are soluble in electrolyte solution like 1,1-dimethyl-4,4’-bipyridinium. • Type2 - these materials will form the solid film on the surface of the electrode like 1,1-diheptyl4,4’bipyridinium dictation in water. • Type3 - these types of materials are in solid form in both oxidized as well as in reduced state like metal oxides and Prussian blue. To make electrochromic devices, a seven-layer electrochemical cell with a rigid sandwich structure is formed. There are two conducting layers sandwiched between the two-substrate layer. Colour changes when there is charging and discharging of the electrochemical cells with a potential of 1-5 V. Five layer and four-layer electrochemical cells are also formed nowadays. To make the four-layer ECD:

Figure 6. Basic design of 4-layer ECD

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The first layer of the device is comprised of polyurethane coated polyester fabric, the conductive layer used is carbon black or silver, the electrochromic compound used is Prussian blue dispersed within a spacer fabric, the second electrode may be PET/ITO and the final layer is transparent, so that colour change may be easily detected. Nowadays, Prussian blue is being replaced by solid organic conducting polymers. As the charging and discharging occurs, the colour change is observed in the transparent layer of the ECD.

Solvatochromic Technique When the colour of the material changes by changing the type of the solvent i.e. when using different solvents leads to different colours, such type of fabric is called solvatochromic fabric. This phenomenon is referred to as solvatochromism [31-32]. This occurs because different types of solvents have different effect on the ground state and the excited state of the electrons of the molecules in the fabric, so the size of the energy gap between them changes as the solvent changes. These materials show negative (hypsochromic) and positive (bathochromic) shifts.

Negative: It is also referred to as the hypsochromic or the blue shift. The colour of the fabric changes to blue colour as the polarity of the solvent increases. An example of that is 4-(4-hydroxystyrl)-N-methylpyridinium iodide, which is red in 1-propanol, orange in methanol and yellow in water.

Positive: It is also referred to as the bathochromic or the red shift. The colour of the fabric changes to red colour as the polarity of the solvent increases. An example of that is 4,4-bis(dimethylamino)fuchsone, which is orange in toluene and red in acetone [32].

DEVELOPMENT OF CAMOUFLAGE COLOURS AND PATTERNS ON TEXTILE MATERIAL Camouflage has been used for ages in the animal kingdom, as well as by humankind, to assist with hunting activities, as well as to assist in survival. The main purpose of the development of camouflage patterns and colours on textile material is to change the properties of a potential target so that it cannot be recognized, or to distinguish possible targets as those of your own and the opposite of your own, or identify the corporate image for a person or the equipment [33]. There are mainly two methods for developing camouflage colours and pattern on the textile material. One is blending, in which colours and patterns are used in such manner that they can blend with the nature. Disruptive pattern material (DPM) is the well-known example for a blended camouflage pattern used by the armed forces worldwide. Another method is disruption, in which the patterning is employed in such a manner that the observer’s attention would not put emphasis on the shape of an object so as to reduce the probability of detection. Dye-sublimation heat transfer printing, fabrics inkjet printer and screen-printing process are common printing methods to produce camouflage patterns on fabric samples. Various researchers have been developing the camouflage pattern for the visible and the near-infrared radiation spectra on different fabric materials. Mehrizi et al. (2012) studied the effect of carbon black nanoparticles on the reflective behaviour of printed cotton/nylon fabrics in the visible/nearinfrared regions [34]. The presence of carbon nanoparticles was found to cause significant decline in the near-infrared (NIR) reflectance of samples. Also, Mehrizi et al. used multi-walled carbon nanotube particles in the printing paste in order to simulate the desert and found considerable decline in the near-infrared

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(NIR) reflectance along with an increase in the visible reflectance of the samples. A significant increase in wetting time was also found. Good crocking, washing and light fastness were found for all the samples [34]. Zhang et al. (2008) concluded that the reflectance of dye is affected by the constitution of dyes in the visible and the NIR region and dyed fabrics imitated the reflectance profile of the greenish leaf based on the NIR camouflage theory [35].

APPLICATIONS OF CAMOUFLAGE FABRICS Camouflage finds its application mainly in the defence sector and a small proportion in various other sectors like in fashionable clothing industry, for decorative purpose etc. Camouflage uses in different sectors are briefly described below: • In apparel grade: camouflage fabrics have existed for more than 75 years and have become very popular since 1990, after the operation Desert Storm in the Middle East by US Forces with NATO Alliances. Today most of the armed forces, including army, navy, air force and paramilitary forces, are using camouflage fabrics, as the fabric increased the safety factor for an individual soldier and the nature of the fabric improved the comfort level and the roughness. It is anticipated that total worldwide requirement of camouflage fabrics is more than 350 million meters annually. Approximately 35 million soldiers worldwide are using camouflage fabrics, which includes army, air force, navy, marines, coastal guards, paramilitary forces etc. [36]. In different countries different types of camouflage fabrics are used. The various fabrics along with their users are described in Figure 7. Digital camouflage (Canada)

Tigerstripe (US Air Force)

Digital camouflage (US Navy)

Flecktarn (Denmark)

Puzzle (Belgium)

Lizard (France)

Woodland (disruptive pattern camouflage) (Australia)

Woodland (desert camouflage pattern) (Thailand)

Flecktarn (for desert and semi-arid regions) (Germany)

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Woodland (Afghan army)

Splinter (Sweden)

Digital (M05) (Finland)

Woodland (Poland)

Moro (Poland)

Figure 7. Camouflage fabric associated with the user country [32, 38, 42]

• In decoration: e.g. the great fancy dress ball given by Chelsea Arts Club at the Albert Hall was based on the motion dazzle principle. • Ships and aircrafts: ships are painted on the principle of motion dazzle camouflage or simply with camouflage pattern so that it might become difficult for the enemy to spot them. This principle was mainly used in the Second World War when painting the ships. Figure 8 shows the motion dazzle of a ship and an aircraft.

Figure 8. (a) Ship with motion dazzle principle (b) Aircraft with disruptive colouration [36-37]

• Land vehicles: Camouflage principle is used to disrupt the shape of the vehicle so that they may not get identified easily. The British army adopted a disruptive scheme for vehicles operating in the stony desert of the North African Campaign. Figure 9 shows the camouflage effect of vehicles in different geographical areas.

Figure 9. (a) Vehicle for desert area with stony desert pattern (b) Vehicle with stripe pattern [37-38]

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• Electrochromic materials are used in glass windows of buildings, for anti-glare car windows, for sun-roof and rear-vision mirrors. Thermochromic prints are also used on the fabric which changes colour when heat or temperature is changed. Figure 10 shows the colour change due to thermochromic print highlighting the floral print on white background by changing from the black colour when heat is supplied.

Figure 10. Colour change due to thermochromic print highlighting floral print on white background by changing from black colour when heat is supplied [22]

EVALUATION OF CAMOUFLAGE FABRIC SAMPLES: Performance of camouflage patterns on the fabric can be evaluated with the help of probability of detection (POD) and pairwise comparison methods. These techniques are described below.

Probability of detection The probability of detection (POD) evaluation technique is mostly used for camouflage evaluation in a laboratory. In POD evaluation technique, firstly a number of observers at a time are observing at a number of targets at different locations. A predetermined path is used by the observer and the distances at which he sees the targets are noted [39]. The second version of this technique, the observer remains stationary at a specific location while the target moves closer. The third version is to photograph the object at different distances; the photographs are then shown to observers on a screen [40]. The probability of the detection of the target is determined by statistical methods. The North Atlantic Treaty Organization (NATO) has formulated an extensive guideline regarding the POD evaluation technique for camouflage evaluation [41]. The results can be predicted in graphical form in which distance from target lies on the x-axis and the probability of detection on the y-axis.

Pairwise comparison methods The law of comparative judgment (LCJ) is the first pairwise comparison method for camouflage evaluation. It is a psychophysical tool for performance evaluation, developed by Thurstone and described by Torgerson (1958) in which different patterns are observed two at a time by a panel of people, and, with the help of statistical method patterns, ranked in terms of visible effectiveness [42-43]. The second pairwise comparison method is known as analytical hierarchy process (AHP). This method gives clear outcome in terms of how much more one pattern is visible in comparison to the other. The benefit of using these psychophysical methods, LCJ and AHP, is that a large number of people is not required for accurate and statistically significant outcome, as is for the POD evaluation method [44].

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RECENT DEVELOPMENT AND FUTURE TRENDS Today camouflage is playing a passive role in the requirement of concealment and deception. Nanotechnology is playing a major role in the future development of camouflage systems on the fabric. Modern technology gives the capability to scientists, engineers and researchers to modify the properties of substrates and surfaces at the molecular level, thereby having the advantage of exploiting (and controlling) certain characteristics of materials and surfaces. Significant research has been contributed to textiles with electrochromic properties for colour change through electric stimulation. Wheaton et al. (2010) gave the concept of using an electrochromic process to change colour panels. The colour of plastic/textile hybrid panels can be changed from yellow to green [45]. It is also investigated that specular reflections are still a problem. Wearable flexible displays are also proposed as an alternative for active camouflage (cloaking) on the textile material. A special material known as metamaterial with special properties is developed by Duke University. These materials are able to ‘bend’ electromagnetic energy around the target in such a manner that the target will be physically present but would not appear to be there. Thermochromic pigments can change colour depending on the temperature of the textile material. Heated panels are being made for camouflage pattern and colours. New developments in thermochromic pigments/dyes have been made stable enough to be used in commercial and consumer markets. Earlier camouflage fabrics were made solely from heavy cotton twill. This heavy fabric can be quite durable, but it is also hot to wear and becomes heavier when wet. After this, the fabrics were prepared from synthetic fibres, but they were unable to absorb sweat. Moreover, pure synthetics are shiny and reflect infrared light. The more effective solution was blending cotton and synthetic fibre which resulted in stronger fabric without increasing weight. Nylon and cotton blends became increasingly common in military uniforms. Nowadays, knitted polyester scrim composition provides increased tensile and tear strength. Moreover, the fabric is flexible and used for all kinds of application like uniforms, tents, helmets, straps to carry weapons etc. The recent development in camouflage fabric is nature–raised fabric which is used for special hunting purpose. This is a special type of fabric which has a different procedure and special properties, such as special textures which refract the light, thus breaking up reflection and stopping the glare or the shine. These types of fabrics are prepared through eight layers and procedures, each of which has a special function and finally makes it suitable for the hunting purpose. The fabric is comprised of natural shapes from nature [45-46]. Active camouflage and multispectral universal camouflage are the area of recent trends on the camouflage fabrics. A system that changes the colour or patterns to match the environment in real time is known as active camouflage. Best example of such research are retroreflective objects which appear transparent. The traditional approach to camouflage design is a semi-random placement of colour and shape to disrupt the target’s true shape, or camouflage patterns that were attempting to mimic natural camouflage to hide an object in the visible spectrum; in both cases these designs actually go too far in random patterns or specific mimicry to provide a better camouflage. Multi-spectral camouflage is being used as a counter-surveillance technique to conceal objects from detection across several parts of the electromagnetic spectrum at the same time. Multi-spectral camouflage also tries to simultaneously hide objects from detection methods such as infrared, radar, and millimetre-wave radar imaging. The emergence of new infrared camouflage and countermeasure technologies in the context of military operations have paved the way to enhanced detection capabilities. Camouflage devices such as candles (or smoke bombs) and flares are developed to generate either large area or localized screens with very high absorption in the infrared spectrum.

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CONCLUSION The principles of camouflage are growing at a fast rate and increasing day by day. The main users of camouflage fabrics are hunters, including game watchers, and the military. Most of the studies focus on the positive aspects of camouflage in the defence sector. But at the same time, if the enemy uses camouflage fabric, it might become difficult for us to spot the enemy. The camouflage fabric creates an illusion for the observer and as a result the camouflaged object becomes blurred or unrecognizable. Furthermore, the cost of the camouflage fabric is higher than the normal grade fabric but if the production of camouflage fabric increases then the cost might decrease. The principles of camouflage are also used for decoration purposes which results in value addition. Researchers are focusing on developing camouflage for known challenges, but as modern warfare dictates, textile manufacturers and researchers must now plan for the unknowable challenges.

REFERENCES [1] Smith D, Black J, Kiley KF. An illustrated encyclopaedia of military uniforms of the 19th century. Oxford: Anness Publishing; 2009. [2] Tian N, Fleurant A, Kuimova A, Peter D, Wezeman ST. Trends in world military expenditure in 2018. Sipri fact sheet. 2019; 1-11. Available from: https://www.sipri.org/publications/2019/sipri-fact-sheets/ trends-world-military-expenditure-2018 [3] McNab C. 20th Century Military Uniforms. 2nd ed. Kent; Grange Books: 2002. [4] Denning RJ. Camouflage fabrics. Engineering of High-Performance Textiles. 2018; 349–375. doi: 10.1016/ b978-0-08-101273-4.00016-0 [5] Sudhakar P, Gobi N, Senthilkumar M. Camouflage fabrics for military protective clothing. In: Eugene Wilusz, editor. Military Textiles. Woodhead Publishing Series in Textiles; 2008. 293-318. Doi: 10.1533/9781845694517.2.293 [6] Barbosa A, Mäthger LM, Buresch KC, Kelly J, Chubb C, Chiao CC, Hanlon RT. Cuttlefish camouflage: The effects of substrate contrast and size in evoking uniform, mottle or disruptive body patterns. Vision Research. 2008; 48(10):1242–1253. Doi: 10.1016/j.visres.2008.02.011 [7] Marini A, Muñoz-Losa A, Biancardi A, Mennucci B. What is Solvatochromism? The Journal of Physical Chemistry B. 2010; 114(51):17128-17135. Doi: 10.1021/jp1097487 [8] Stevens M. Colour Change, Phenotypic Plasticity and Camouflage. Frontiers in Ecology and Evolution. 2016; 4(51):1-10. Doi: 10.3389/fevo.2016.00051 [9] Kelley L. The Conversation [Internet]. 2015. Available from: https://theconversation.com/motiondazzle-spotting-the-patterns-that-help-animals-outsmart-predators-on-the-run-47219 [10] National Geographic [Internet]. 2019. Available from: https://www.nationalgeographic.com/animals/ reference/camouflage-explained/ [11] Kovacevic S, Gudlin Schwarz I, Durasevic V. Analysis of printed fabrics for military camouflage clothing. Fibres and Textiles in Eastern. Europe. 2012; 3(92):82–86. [12] Worbin L. Textile disobedience when textile patterns start to interact. The Nordic Textile Journal. 2005; 51–69. [13] Sudhakar P, Gobi N, Senthilkumar M. Camouflage fabrics for military protective clothing. In: Eugene Wilusz, editor. Military Textiles. Woodhead Publishing Series in Textiles; 2008. 293-318. Doi: 10.1533/9781845694517.2.293

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[14] Periyasamy AP, Vikova M, Vik M. A review of photochromism in textiles and its measurement. Textile Progress. 2017; 49: 53-136. Doi: 10.1080/00405167.2017.1305833 [15] Seipel S, Yu J, Viková M, Vik M, Koldinska M, Havelka A, Nierstrasz VA. Colour performance, durability, and handle of inkjet-printed and UV-cured photochromic textiles for multi-coloured applications. Fibres and Polymers. 2019; 20:1424-1435. Doi: 10.1007/s12221-019-1039-6 [16] Rubeziene V, Padleckiene I, Baltusnikaite J, Varnaite S. Evaluation of camouflage effectiveness of printed fabrics in visible and near infrared radiation spectral ranges. Journal of Material Science. 2008; 14: 361–365. [17] Aldib M, Christie RM. Textile applications of photochromic dyes. Part 4: application of commercial photochromic dyes as disperse dyes to polyester by exhaust dyeing. Colouration Technology. 2011; 127:282-287. Doi: 10.1111/j.1478-4408.2011.00308.x [18] Bamfield P, Hutchings M. Chromic Phenomena. 3rd Edition. Royal Society of Chemistry; 2018. 782 p. [19] Vik M, Periyasamy AP, Vikova M. Chromic Materials, Fundamentals, Measurements and Applications. Waretown, New Jersey: Apple Academic Publishing; 2018. [20] Friskovec M, Gabrijelcic H. Development of a procedure for camouflage pattern design. Fibres and Textiles in Eastern Europe. 2010; 18 4(81):68-76. www.fibtex.lodz.pl/file-Fibtex_(q5xadlkx018y8qji). pdf-FTEE_81_68.pdf [21] Vikova M, Pechova M. Study of adaptive thermochromic camouflage for combat uniform. Textile Research Journal. 2020; 90(17-18):2070-2084. Doi: 10.1177/0040517520910217 [22] Karpagam KR, Saranya KS, Gopinathan J, Bhattacharyya A. Development of smart clothing for military applications using thermochromic colourants. The Journal of The Textile Institute. 2017; 108(7):11221127. Doi: 10.1080/00405000.2016.1220818 [23] Basnec K, Perse L, Sumiga B, Huskic M, Meden A, Hladnik A, Boh Podgornik B, Klanjsek Gunde M. Relation between colour and phase changes of a leuco dye-based thermochromic composite. Scientific Reports. 2018; 8(5511). Doi:10.1038/s41598-018-23789-2 [24] Strizic Jakovljevic M, Kulcar R, Friskovec M, Lozo B, Klanjsek Gunde M. Light fastness of liquid crystal based thermochromic printing inks. Dyes and Pigments; 2020; 180. doi: 10.1016/j.dyepig.2020.108482 [25] Chowdhury MA, Joshi M, Butola BS. Photochromic and thermochromic colourants in textile application. Journal of Engineered Fibres and Fabrics 2014; 9(1):107–123. Doi: 10.1177/155892501400900113 [26] Xu JW, Chua MH, Shah KW. Electrochromic Smart Materials: Fabrication and Applications, UK: The Royal Society of Chemistry; 2019. 23-39 p. [27] Ludivine M, Kelly FM, Cochrane C, Koncar V. Flexible displays for smart clothing: part 2-Electrochromic displays. Indian Journal of Fibre and Textile Research. 2011; 36(4):429-435. [28] Ferrara M, Bengisu M. Materials that Change Colour: Smart Materials, Intelligent Design. Springer Briefs in Applied Sciences and Technology. Springer; 2014. 9-60 p. [29] Stasiek JA, Kowalewski TA. Thermochromic liquid crystals applied for heat transfer research. Proc. SPIE 4759, XIV Conference on Liquid Crystals: Chemistry, Physics, and Applications, (27 June 2002). 2002. Doi: 10:1–10 DOI: 10.1117/12.472179 [30] Chen J, Wen H, Zhang G, Lei F, Feng Q, Liu Y, Cao X, Dong H. Multifunctional conductive hydrogel/ thermochromic elastomer hybrid fibres with a core–shell segmental configuration for wearable strain and temperature sensors. ACS Applied Materials & Interfaces. 2020; 12 (6): 7565-7574. DOI: 10.1021/ acsami.9b20612.

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[31] Smith C, Sabatino D, Praisner T. Temperature sensing with thermochromic liquid crystals. Experiments in Fluids. 2001; 30: 190. https://doi.org/10.1007/s003480000154 [32] Zhao J. Luo W, Qi L, Yuan L, Huang G, Huang Y, Weng X. The High-Temperature Resistance Properties of Polysiloxane/Al Coatings with Low Infrared Emissivity. Coatings. 2018; 8(4):125. Doi: 10.3390/ coatings8040125 [33] Fortuniak K, Redlich G, Obersztyn E, Olejnik M, , Bartczak A, Krol I. Assessment and verification of functionality of new, ulticomponent, camouflage materials. Fibres and Textiles in Eastern Europe. 2013; 21(5):73-79. Available from: http://fibtex.lodz.pl/article991.html [34] Khajeh Mehrizi M, Mortazavi SM, Mallakpour S, Bidoki SM, Vik M, Vikova M. Effect of carbon black nanoparticles on reflective behaviour of printed cotton/nylon fabrics in visible/near infrared regions. Fibres and Polymers. 2012; 13(4):501-505. doi: 10.1007/s12221-012-0501-5 [35] Zhang H, Zhang JC. Near-infrared green camouflage of cotton fabrics using vat dyes. The Journal of the Textile Institute. 2008; 99(1):83-89. Doi: 10.1080/00405000701556392 [36] Christie RM. Chromic material for technical textile application. In: Gulrajani ML, editor. Advances in Dyeing and Finishing of Technical Textiles. Cambridge Woodhead Publishing; 2013. P. 3-36. [37] Hughes A, Liggins E, Stevens M. Imperfect camouflage: how to hide in a variable world? Proceedings of the Royal Society B: Biological Sciences. 2019; 286(1902):20190646. Doi: 10.1098/rspb.2019.0646 [38] Jia Q, Xu WD, Hu JH, Liu J, Yang X, Zhu LY. Design and evaluation of digital camouflage pattern by spot combination. Multimedia tools and Applications. 2020; 79:22047-22064. Doi: 10.1007/s11042-02009002-5 [39] Anitole G, Johnson RL, Neubert CJ. Evaluation of Camouflage Paint Gloss versus Detection Range. Thirty-third Conference on the Design of Experiments in Army Research Development and Testing. Delaware. 1988; 37– 45. [40] Technical Report Natick/TR-09/02IL. Photosimulation camouflage detection test. U.S. Army Natick Soldier Research, Development and Engineering Center, Massachusetts. 2009. [41] NATO. Guidelines for Camouflage Assessment Using Observers, AG-SCI-095, NATO Research & Technology Organisation (RTO). 2006. [42] Torgerson WS. Theory and Methods of Scaling. USA: John Wiley & Sons Inc; 1958. [43] Troscianko T, Benton CP, Lovell PG, Tolhurst DJ, Pizlo Z. Camouflage and Visual Perception, Philosophical Transactions of the Royal Society B: Biological Sciences. 2009; 364:449–461. Doi: 10.1098/rstb.2008.0218 [44] McManamey JR. Comparative evaluation of technologies for camouflage performance assessment. US Army ARDECOM, CECOM, Fort Belvoir; 2003. [45] Wheaton W, Vincent I, Dumas J. Adaptive camouflage techniques for a light armoured vehicle. Land Warfare Conference 2010, Brisbane. 2010; 725:30. [46] Talas L, Baddeley RJ, Cuthill IC. Cultural evolution of military camouflage. Philosophical Transactions of the Royal Society B: Biological Sciences. 2017; 372: 20160351. Doi: 10.1098/rstb.2016.0351

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MURALIDHAR BA. Characterization of Sisal/Polypropylene Composites Treatedâ&#x20AC;Ś TLR 3 (4) 2020 202-212.

Characterization of Sisal/Polypropylene Composites Treated with Plasma BA MURALIDHAR Department of Textile Technology, A. C. Tech. Anna University, Sardar Patel Road, Guindy, Chennai 600025, India muralidharba@annauniv.edu Original scientific article UDC 677.162:677.494.742:677.014 DOI: 10.31881/TLR.2020.15 Received 25 Jul 2020; Accepted 29 Aug 2020; Published Online 11 Sep 2020; Published 1 Dec 2020

ABSTRACT In this study, sisal/polypropylene composites were experimentally investigated for their flexural, thermal and water absorption characteristics. The effect of oxygen (O), argon (Ar) and ammonia (NH3) plasmas on the surface of the sisal fibre as well as the effect of the sisal fibre content on the above mentioned properties was studied. The composite laminates (4 mm thick) were processed by hand lay-up technique by using a compression moulding machine, with the mould temperature of 165oC and the pressure of 6.89 x 10 2 kPa for 15 minutes. Specimen preparation and testing were carried out as per ASTM standards. Flexural data obtained showed that the plasma-treated sisal fibre-reinforced polypropylene offered superior flexural properties compared to untreated laminates, which indicated better adhesion between the sisal fibre and the untreated polypropylene matrix. Thermal investigations revealed that the sisal/polypropylene composite had its thermal stability in between that of the fibre and the matrix. Furthermore, the water absorption studies indicated that plasma treatment decreased the water uptake of the laminates, thereby leading to better fibre-matrix adhesion. Morphological studies were carried out by using SEM to complement the results. KEYWORDS Plasma treatment, Natural fibre, Sisal fibre, Polypropylene, Composites

INTRODUCTION In recent years, there has been an ever-growing demand for lignocellulosic fibres, also called natural, plant or vegetable fibres. Among them sisal, flax, hemp, jute and other bast fibres are a group of environmentally friendly reinforcement in composites from a wide variety of thermoplastics matrices, including polypropylene, polyethylene, polystyrene and polyvinyl chloride. These natural fibres are very popular as reinforcements due to some of their unique characteristics, such as biodegradability, renewability, low cost, availability, density, reduced health hazard, no damage to processing equipment and reasonable stiffness and strength. Among natural fibres, the sisal (Agave sisalana) fibre removed from the leaves of the sisal plant is categorized as a hard fibre, with length between 1 to 1.5 meter and thickness about 0.1 to 0.3 mm [1]. It is composed of cellulose (78%), hemicellulose (10%), lignin (8%), wax (2%) and ash (1%) [2]. At 20Â° microfibrillar angle, the sisal fibre has much higher strength and good specific properties than other natural fibres due to its low density [3]. These exceptional mechanical properties of sisal fibres have consequently increased the enthusiasm to use sisal fibres in a variety of industrial applications, such as automo202 www.textile-leather.com

MURALIDHAR BA. Characterization of Sisal/Polypropylene Composites Treatedâ&#x20AC;Ś TLR 3 (4) 2020 202-212.

tive, aviation, construction, packaging etc. However, there are some drawbacks associated with its application along with polymeric matrices. Natural materials which are hydrophilic in nature, with the increase in hydroxyl groups, tend to absorb moisture from the atmosphere and become wet, thereby leading to poor interfacial adhesion. Furthermore, the difference between the properties of highly polar natural fibres and the less or non-polar polymeric counterpart also causes low interfacial adhesion. Conversely, Adriana et al. [4] have observed in their study that plasma-treated high-density polyethylene (HDPE) and untreated sisal fibre composites recorded higher tensile strength values compared to the plasma-exposed sisal and the untreated HDPE. As such, these dissimilar materials exhibit poor stress transfer from the matrix to the reinforced fibres resulting in poor mechanical properties [5]. Furthermore, the structure and properties of fibres play a vital role on the manufacturing processes. Many properties, like the shrinkage, adhesion, wettability, static charge generation, pilling, soil resistance etc. are governed by the surface characteristics of the fibres which can induce desired functionality to the substrate [6]. A great deal of work on surface modification has been carried out by using conventional wet-processing techniques such as chemical modification, addition of compatibilizers or plasma treatment to improve the adhesion. Favaro et al. [7], in their studies on sisal fibre-reinforced recycled high-density polyethylene composites, have chemically modified sisal fibres and the polyethylene (PE) matrix to improve their compatibility. Sisal fibres were mercerized and acetylated, whereas the PE matrix was oxidized. The obtained results demonstrated that the composites prepared with modified sisal fibres and the unmodified polyethylene showed improved mechanical properties, but no benefits were obtained by the modified PE. Joseph et al. [8] investigated the effect of fibre content and chemical treatments on thermal properties of sisal/polypropylene (PP) composites and have reported that the treated fibres show superior properties compared to the untreated system. Kalaprasad et al. [3] studied the effect of fibre length and chemical modifications on sisal/glass hybrid low-density polyethylene composites by varying fibre lengths in the range of 1-10 mm. Fibre-matrix adhesion characteristics with several fibre chemical modifications were found to be successful in improving the interfacial adhesion. Of all the surface modification techniques, plasma treatment is a clean and dry technology which offers many advantages as it is considered environmentally friendly and economical, due to the reduced treatment time and the reduction of chemicals used compared to the other chemical processes [4,6,9,10]. Plasma consists of reactive species like the ions, electrons as well as neutral species, which makes it a unique medium for surface modification. It is often referred to as the fourth state of matter [11]. When polymer surfaces are exposed to plasma, different effects are often observed, such as modification of the chemical composition, etching, surface cleaning etc. Plasma treatment can bring changes to the surface topography without altering the bulk properties. Kafi et al. [12] in their study on jute fibres found that the plasma treatment of jute induced some changes in the surface chemistry and topography which were accompanied by the improvement in the final composite materials. Hua et al. [5] in their analysis with Ar- and O2-RF-plasma treatments have reported that both plasmas create HC=O, O-C=O and O-CO-O functionalities on cellulose substrates. Furthermore, Ar-plasma was associated with the cleavage of C1-C2 linkages while O2-plasma was associated with more intense C-O-C bonds splitting mechanism. However, prolonged exposure to plasma has shown to decrease the adhesion characteristics [9] leading to measurable changes in the mechanical properties. Furthermore, there are still other disadvantages, such as the degradation induced by moisture absorption, causing a swelling. Owing to the swelling process, the fibre-matrix interface is weakened which leads to the mechanical degradation of composites. Additionally, thermal analysis is a useful technique to quantify the amount of moisture and volatiles present in composite laminates [13]. Furthermore, with respect to cellulosic materials, the degradation that sets in at around 200Â°C determines the thermal stability of the materials. As such, in this study, the effect of plasma treatment on sisal fibres and the influence of the fibre content www.textile-leather.com 203

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on the flexural, thermal and moisture absorption are reported. Sisal fibres were treated with oxygen, argon and ammonia plasma. The purpose of using these three gases was to find the conditions that yield the best results and to establish optimum conditions.

EXPERIMENT Materials and Methods Sisal fibres were purchased from local sources. These fibres were approximately 1-1.5 m in length. The longer length made it easier to perform the plasma treatment on the fibres. Typical chemical compositions of sisal fibres are shown in Table 1 [2]. The plasma-treated fibres were then cut into 30 mm long pieces by using hand shears. Only the central part of the fibre has been used as reinforcement. A 1 mm thick polypropylene film with a melting temperature of 160oC was used as a matrix in this study. Table 1. Composition and density of sisal fibres [2] Cellulose (%)

Hemicellulose (%)

Lignin (%)

Pectin (%)

Wax (%)

Density (g/cm3)

67.0-78.0

10.0-14.2

8.0-11.0

10.0

2.0

1.45

Fibre surface modification Plasma treatment was used to functionalize the surface of sisal fibres under selected plasma conditions. Glowischarge atmospheric plasma treatment was carried out with a Hydro Pneo Vac Technologies plasma device (HPVT – PS, India), equipped with an aluminium-type electrode, with the system frequency of 60 kHz. The sisal fibres were treated with oxygen of high purity, argon and ammonia; these gases were used as a plasma medium in the plasma chambers. Plasma cleaning of the chamber walls was carried out with respective gases, at 80 W, with the pressure of 9 x 10 -2 kPa for the duration of 5 minutes before treating the test specimens. The prepared sisal fibres were then arranged on a rectangular specimen holder (51 x 55 cm) and placed between two electrodes charged at 60 W, at a pressure of 9 x 10 -2 kPa, and treated for 10 minutes. After the treatment the samples were stored and sealed for composite preparation.

Fabrication of composites The composite laminates were fabricated by hand lay-up method. The sisal fibres were cut into 30 mm long pieces and evenly dispersed during manufacturing. The laminate plates were fabricated by using 4 mm thick spacer between the press plates with the fibre content of 15%, 25% and 35%. 1 mm thick polypropylene films were used as the matrix. Laminates were cured in a hot-plate press for 15 minutes at 165°C with the pressure of 6.89 x 102 kPa. Each of the laminates was then slowly cooled to room temperature while still under pressure.

Mechanical Properties Flexural testing Flexural strength and flexural modulus were determined by using the three-point bending method as per American Society for Testing and Materials (ASTM) standard D790, with the span length 16 times the thickness and the crosshead speed of 1.3 mm/min, by using an Instron testing machine (Model 3369). All tests were conducted at 27±2°C and 65±2% relative humidity, allowing prior specimen conditioning for 24 hours. 204 www.textile-leather.com

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At least five specimens were tested each type. Flexural modulus (Ef) and flexuralTreatedâ&#x20AC;Ś strengthTLR (Ď&#x192;f00) were calcuMURALIDHAR BA.for Characterization of Sisal/Polypropylene Sisal/Polypropylene Composites Treatedâ&#x20AC;Ś TLR (0) 2020 2020 00-00. MURALIDHAR BA. Characterization of Composites (0) 00-00. lated by using the following equations: 3 đ?&#x2018;&#x161;đ?&#x2018;&#x161;đ?&#x2018;&#x161;đ?&#x2018;&#x161; đ?&#x2018;&#x161;đ?&#x2018;&#x161;đ?&#x2018;&#x161;đ?&#x2018;&#x161;3 đ??¸đ??¸ = đ??¸đ??¸đ?&#x2018;&#x201C;đ?&#x2018;&#x201C;đ?&#x2018;&#x201C;đ?&#x2018;&#x201C; = 4đ?&#x2018;?đ?&#x2018;?đ?&#x2018;?đ?&#x2018;?33 4đ?&#x2018;?đ?&#x2018;?đ?&#x2018;?đ?&#x2018;? 3đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x161;đ?&#x2018;&#x161; đ?&#x153;&#x17D;đ?&#x153;&#x17D;đ?&#x2018;&#x201C;đ?&#x2018;&#x201C;đ?&#x2018;&#x201C;đ?&#x2018;&#x201C; = = 3đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x161;đ?&#x2018;&#x161;2 đ?&#x153;&#x17D;đ?&#x153;&#x17D; 2đ?&#x2018;?đ?&#x2018;?đ?&#x2018;?đ?&#x2018;? 2đ?&#x2018;?đ?&#x2018;?đ?&#x2018;?đ?&#x2018;? 2

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Impact strength The impactImpact behaviour of a composite laminate is related to the overall toughness of the composite and is strength Impact strength defined as its ability to resist damage under applied stress. Figure 3 shows the variation of work of rupture The The impact impact behaviour behaviour of of aa composite composite laminate laminate is is related related to to the the overall overall toughness toughness of of the the composite composite of plasma for the treated and the untreated sisal/polypropylene reinforced epoxy composites. Impact tests and is defined as ability to damage applied stress. Figure shows the variation of and defined as its its test ability to resist resist according damage under under applied stress. Figure 3 3tests shows thecarried variation were carried outison unnotched specimens to ASTM D256. The impact were outof work of plasma for and the reinforced work of of rupture rupture of impact plasma speed for the theoftreated treated andincident the untreated untreated sisal/polypropylene reinforced epoxy epoxy at room temperature with an 4ms-1 and energysisal/polypropylene of 4 J. composites. composites. Impact Impact tests tests were were carried carried out out on on unnotched unnotched test test specimens specimens according according to to ASTM ASTM D256. D256.

Thermogravimetric (TGA) The impactanalysis tests were carried out at room temperature with an impact speed of 4ms-11 and incident The impact tests were carried out at room temperature with an impact speed of 4ms- and incident

of The thermalenergy stability energy of 4 4ofJ. J. samples was assessed by Q50 series T. A. Instrumentâ&#x20AC;&#x2122;s apparatus. The test specimens of 5 mg were placed in a platinum pan, heated from 20Â°C to 700Â°C at a heating rate of 10Â°C/min in a nitrogen atmosphere with a flow rate (TGA) of 60 ml/min to avoid unwanted oxidation. Thermogravimetric analysis Thermogravimetric analysis (TGA)

The thermal stability of samples was assessed by Q50 series T. A. Instrumentâ&#x20AC;&#x2122;s apparatus. The test

The thermal stability of samples was assessed by Q50 series T. A. Instrumentâ&#x20AC;&#x2122;s apparatus. The test Moisture absorption

specimens specimens of of 5 5 mg mg were were placed placed in in aa platinum platinum pan, pan, heated heated from from 20Â°C 20Â°C to to 700Â°C 700Â°C at at aa heating heating rate rate of of

Moisture absorption studies wereatmosphere carried out witharectangular-shaped test specimens measuring 76.2 mm 10Â°C/min 10Â°C/min in in aa nitrogen nitrogen atmosphere with with a flow flow rate rate of of 60 60 ml/min ml/min to to avoid avoid unwanted unwanted oxidation. oxidation. x 25.4 mm x 4 mm as per ASTM D570. All the test specimens were dried in an oven at 105-110Â°C for 1 hour. Then the specimens were weighed with a digital analytical balance with a Âą0.001 mg sensitivity. Following Moisturewere absorption Moisture absorption this the specimens fully immersed in distilled water at room temperature for 24 hours. After 24 hours Moisture absorption studies were carried out with test measuring of immersion the specimens were removed water, dry with a piece of cloth and weighed again Moisture absorption studies werefrom carried outwiped with rectangular-shaped rectangular-shaped test specimens specimens measuring with the same Themm moisture was calculated thespecimens differencewere in weight and at after 76.2 mm xx 4 as D570. the dried in 10576.2balance. mm xx 25.4 25.4 mm 4 mm mmcontent as per per ASTM ASTM D570. All All from the test test specimens were driedbefore in an an oven oven at 105immersion.110Â°C for 1 hour. Then the specimens were weighed with a digital analytical balance with a Âą0.001 110Â°C for 1 hour. Then the specimens were weighed with a digital analytical balance with a Âą0.001

mg the specimens specimens were were fully fully immersed immersed in in distilled distilled water water at at room room mg sensitivity. sensitivity. Following Following this this the RESULTS AND DISCUSSION

temperature temperature for for 24 24 hours. hours. After After 24 24 hours hours of of immersion immersion the the specimens specimens were were removed removed from from water, water,

Flexural tests

wiped wiped dry dry with with aa piece piece of of cloth cloth and and weighed weighed again again with with the the same same balance. balance. The The moisture moisture content content was was

Flexural strength is the capability of a material to before bear bending forces applied to its longitudinal axis [14]. calculated from the in and immersion. calculated from the difference difference in weight weight before and after after immersion. The stresses induced due to the flexural load are a combination of tensile, shear and compressive stresses. The composite laminate in flexural testing was loaded by using a three-point bend test until the specimen RESULTS RESULTS AND AND DISCUSSION DISCUSSION deflected and ruptured at the outer surface [5,9]. Flexural properties were calculated and reported in terms Flexural tests Flexural tests of the maximum stress and strain that occur at the outside surface of the test specimen. The flexural strength Flexural strength the of bear forces applied to axis strength isuntreated the capability capability of aa material material to to composites bear bending bendingand forces applied to its its longitudinal axis and flexuralFlexural modulus of the is sisal/polypropylene those treated by longitudinal plasma gases [14].and Theammonia) stresses induced induced due fibre to the the flexural load are are aaare combination of tensile, tensile, shear and and (oxygen, argon with various content percentages shown in Table 2 and separate [14]. The stresses due to flexural load combination of shear charts for flexural strength and flexural moduluslaminate are depicted in Figures compressive stresses. The in testing was loaded compressive stresses. The composite composite laminate in flexural flexural testing1 and was 2. loaded by by using using aa three-point three-point www.textile-leather.com 205

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Table 2. Flexural strength and flexural modulus of treated and untreated composite laminates Test specimen

Untreated

Oxygen plasma-treated

Ammonia plasmatreated

Argon plasma-treated

Laminate thickness (mm)

Weight fraction (%)

Flexural strength (MPa)

Flexural modulus (GPa)

Flexural strain at max. flexural stress (%)

63.26

4.05

2.81

82.21

4.71

3.45

44.08

1.98

3.51

110.49

6.66

2.93

118.70

6.85

3.23

57.29

3.60

2.78

87.36

4.78

3.72

108.31

7.17

2.59

55.30

2.38

4.59

71.79

3.25

3.97

81.55

5.75

2.67

54.70

2.05

6.09

Flexural behaviour of untreated specimens It can be noted that the flexural strength and the flexural modulus of the untreated test specimens were lower compared to the plasma-treated specimens. Among the untreated specimens with three different fibre content percentages, the flexural strength was highest for those with 25% fibre content and lowest for those with 35% fibre content, implying that the flexural properties improved with the increase in the fibre weight fraction from 15% to 25%; beyond this, the properties deteriorated drastically. The lower flexural strength and flexural modulus with respect to the 15% fibre content could be attributed to a lack of reinforcing fibres to share the load, whereas the poor behaviour of 35% fibre content laminate could be attributed to poor wetting of the sisal fibre reinforcements by the matrix. As such, the matrix has not been able to transfer the stress completely to the fibres leading to their poor behaviour.

Flexural behaviour of plasma-treated specimens It can be seen that the plasma-treated sisal/polypropylene composites have much higher flexural strength and flexural modulus than the untreated sisal polypropylene composites, irrespective of the type of plasma gas used. Among the three plasma gases used for treatment, the flexural properties of composite laminates treated with oxygen gas showed significant improvements compared to ammonia and argon plasmatreated specimens. From Figures 1 and 2 it can be inferred that with the increase in fibre content from 15% to 25% weight fraction, there is an increase in flexural strength and flexural modulus. This trend is observed for both the treated and the untreated sisal fibre composites, where these values are highest at 25% fibre weight fraction. However, the flexural strength of the 15%, 25% and 35% fibre weight fraction composite laminates improved by approximately 74%, 43% and 29% respectively with oxygen plasma, 38%, 31% and 25% respectively with ammonia plasma and 12%, 2% and 22% respectively with argon plasma treatment compared to the untreated composite laminates, whereas the flexural modulus was 66%, 45% and 81% respectively with oxygen plasma, 19%, 51% and 20% respectively with ammonia plasma and -18%, 22% and 3% respectively with argon plasma treatment compared to the untreated composite laminates. The above results could be attributed to poor adhesion at the fibre-matrix interface [9]. 206 www.textile-leather.com

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Figure 1. Effect of plasma treatment process on flexural strength

Figure 2. Effect of plasma treatment process on flexural modulus

Impact test Impact behaviour of the unnotched plasma-treated and the untreated sisal/polypropylene composite laminates is represented in Figure 3. It can be observed that plasma treatment significantly increases the unnotched impact toughness of composites. The highest impact toughness values are associated with the argon-treated sisal fibre composites. This data also substantiates the earlier conclusion that the exposure of sisal fibres to plasma might induce significant surface decomposition and surface cross-linking reaction mechanisms which obviously will limit the molecular interaction on both oxygen- and ammonia-treated sisal fibres/polypropylene interface. Furthermore, the impact strength increases with the increase in fibre weight fraction, but at 35% fibre content the strength goes down, because, as the fibre weight increases in the composite, it tends to decrease the matrix component, thereby impairing the stress transfer.

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Figure 3. Impact strength of treated and untreated sisal/polypropylene laminates with 15%, 25% and 35% fibre content

Thermogravimetric analysis The thermal stability of the sisal fibres, the neat polypropylene and the untreated sisal/polypropylene reinforced composites were examined with thermogravimetric analysis (TGA). The temperature at which considerable weight loss starts to take place is taken as a basis to assess the thermal stability. Thermal stability parameters, such as the initial degradation temperature, the final degradation temperature and the residual char content are presented in Table 3. The investigation was carried out in the temperature range of 20°C700°C. The TGA curves of the sisal fibres, the neat polypropylene and the untreated sisal/polypropylene composite laminates containing 15%, 25% and 35% fibre weight fraction are shown in Figure 4. From the curves it can be observed that the sisal fibre degradation after dehydration occurs in the temperature range of 60°C-200°C. With the further increase in the temperature to about 350°C, most of the cellulose is decomposed, whereas polypropylene was decomposed at a higher temperature than the sisal fibres, at around 430°C. The TGA curves of the untreated sisal/polypropylene composites reveals that in all the three laminates (15%, 25 % and 35%) the fibres degrade before the virgin polypropylene, thus indicating that the thermal stability of a composite is higher than that of a fibre and lower than that of a matrix [8]. At around 700°C the specimens with 35% weight fraction possess the highest char residue because of the higher cellulose content. Table 3. Thermal properties of sisal fibres, polypropylene and untreated sisal/polypropylene laminates with 15%, 25% and 35% fibre content Degradation temperature (°C) Composites

Initial degradation temperature

Final degradation temperature

Char residue (%)

Sisal fibre

230

390

13.79

Neat PP

350

490

0.18

15% Laminate

310

480

2.23

25% Laminate

300

470

3.23

35% Laminate

280

470

8.28

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Figure 4. TGA curves of sisal fibres, polypropylene, untreated sisal/polypropylene laminates with 15%, 25% and 35% fibre content

Water absorption Figure 5 shows the water absorption behaviour of various treated sisal/polypropylene composites with 15%, 25% and 35% fibre content. It is observed that the sisal fibre-reinforced laminates absorb water. The water uptake increased with the increase in fibre percentage. With different plasma treatments the water uptake also varies. The treated laminates show lower water absorption levels, which can be attributed to the surface modification which has induced chain scission leading to the formation of free radicals. These free radicals have improved the adhesion between sisal fibres and the polypropylene resin, rendering the sisal fibres hydrophobic and in turn leading to a better stress transfer at the fibre-matrix interface.

Figure 5. Water absorption behaviour of treated and untreated sisal/polypropylene composites

SEM micrograph The SEM analysis photomicrographs of the treated and the untreated sisal/polypropylene composites are shown in Figure 6. The samples were fractured in flexural testing prior to the observation with scanning electron microscopy (SEM). In the micrographs of the untreated sisal/polypropylene composite presented in Figure 6(a) it is possible to observe a clear fibre pulled out without any matrix adhered to the fibre surface, suggestive of non-existence of phase adherence, with further local stress whitening regions indiwww.textile-leather.com 209

MURALIDHAR BA. Characterization of Sisal/Polypropylene Composites Treatedâ&#x20AC;Ś TLR 3 (4) 2020 202-212.

cating excessive matrix straining leading to poor stress transfer to the reinforcement. However, the oxygen plasma-treated specimen presented in Figure 6(b) shows an increase in adhesion between the phases, and the sisal fibres revealed globular protrusions or patches with the matrix adhered at a few places with some observable micropores [15]. From the argon- and ammonia-treated specimens viewed in Figure 6(c) and 6(d) it was observed that the adhesion was nonhomogeneous, with the specimen presenting regions of non-adherence, fibre damage, fibrillation and cracks. All of that can be attributed to poor mechanical properties of composites treated with argon and ammonia plasma.

Figure 6. (a) SEM photography of fracture surface of untreated sisal fiber 25% mass fraction composite

Figure 6. (b) SEM photography of fracture surface oxygen treated sisal fiber 15% mass fraction composite

Figure 6. (c) SEM photography of fracture surface of argon treated sisal fiber 35% mass fraction composite

Figure 6. (d) SEM photography of fracture surface of ammonia treated sisal fiber 25% mass fraction composite

CONCLUSION Sisal/polypropylene composites reinforced with untreated and plasma-treated sisal fibres were fabricated by hand lay-up techniques. Sisal fibres were treated with oxygen, ammonia and argon plasma in selected plasma conditions. The flexural, impact, thermal and water absorption characteristics and the morphology of the fractured specimen were studied. It was observed that the oxygen plasma treatment was very effective in improving the adhesion as observed by other researchers [9]. SEM photomicrographs demonstrate the interfacial adhesion between the oxygen plasma-treated sisal fibres and the unmodified polypropylene. 210 www.textile-leather.com

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The treatment of sisal fibres with ammonia and argon plasma was not as effective as with oxygen plasma, which explains the poor flexural properties of its composites. Thermogravimetric investigation was carried out to study the thermal stability of sisal/polypropylene composites with reference to the fibre content. It was found that most of the cellulose in the sisal fibres was decomposed at around 350°C, well before the polypropylene decomposition started, which occurred at 430°C. It was also observed that the sisal/polypropylene composite had its thermal stability in between that of the fibre and the matrix, due to the poor fibre-matrix adhesion [7]. The water absorption studies showed that the treatment decreases the water uptake of the plasma-treated laminates, thereby leading to better fibre-matrix adhesion [16]. Acknowledgements The author would like to thank the Head of Textile Technology Department, for their support in allowing him to perform the tests. The study was carried out without any financial support from any external funding agency.

REFERENCES [1] Bisanda ETN, Ansell MP. The effect of silane treatment on the mechanical and physical properties of sisal-epoxy composite. Composites Science and Technology. 1991; 41(2):165-178. Doi: 10.1016/02663538(91)90026-L [2] Kim JT, Netravali AN. Mercerization of sisal fibres: effect of tension on mechanical properties of sisal fibre and fibre-reinforced composites. Composites Part A: Applied Science and Manufacturing. 2010; 41(9):1245-1252. Doi: 10.1016/j.compositesa.2010.05.007 [3] Kalaprasad G, Francis B, Thomas S, Radhesh Kumar C, Pavithran C, Groeninckx G, Thomas S. Effect of fibre length and chemical modifications on the tensile properties of intimately mixed short sisal/glass hybrid fibre reinforced low density polyethylene composites. Polymer international. 2004; 53(11):16241638. Doi: 10.1002/pi.1453 [4] Martin AR, Denes FS, Rowell RM, Mattoso LHC. Mechanical behaviour of cold plasma-treated sisal and high-density polyethylene composites. Polymer composites. 2003; 24(3):464-474. Doi: 10.1002/ pc.10045 [5] Hua ZQ, Sitaru R, Denes F, Young RA. Mechanisms of oxygen-and argon- Rf- plasma- induced surface chemistry of cellulose. Plasmas and polymers. 1997; 2:199-224. Doi: 10.1007/BF02766154 [6] Kale KH, Desaia AN. Atmospheric pressure plasma treatment of textile using non-polymerising gases. Indian Journal of Fibre and Textile Research. 2011; 36(3):289-299. [7] Favaro SL, Ganzerli TA, De Carvalho Neto AGV, Da Silva ORRF, Radovanovic E. Chemical, morphological and mechanical analysis of sisal fibre-reinforced recycled high-density polyethylene composites. Express Polymer Letters. 2010; 4(8):465-473. Doi: 10.3144/expresspolymlett.2010.59 [8] Joseph PV, Joseph K, Thomas S, Pillai CKS, Prasad VS, Groeninckx G, Sarkissova M. The thermal and crystallisation studies of short sisal fibre reinforced polypropylene composites. Composites Part A: Applied Science and Manufacturing. 2003; 34(3):253-266. Doi: 10.1016/S1359-835X(02)00185-9 [9] Couto E, Tan IH, Demarquette N, Caraschi JC, Leao A. Oxygen plasma treatment of sisal fibres and polypropylene: effects on mechanical properties of composites. Polymer Engineering and Science. 2002; 42(4):790-797. Doi: 10.1002/pen.10991

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[10] Yuan X, Jayaraman K, Bhattacharyya D. Effects of plasma treatment in enhancing the performance of woodfibre-polypropylene composites. Composites Part A: Applied Science and Manufacturing. 2004; 35(12):1363-1374. Doi: 10.1016/j.compositesa.2004.06.023 [11] Bogaerts A, Neyts E, Gijbels R, van der Mullen J. Gas discharge plasmas and their applications. Spectrochimica Acta Part B: Atomic Spectroscopy. 2002; 57(4):609-658. Doi: 10.1016/S05848547(01)00406-2 [12] Kafi AA, Magniez K, Fox BL. A surface-property relationship of atmospheric plasma treated jute composites. Composites Science and Technology. 2011; 71(15):1692-1698. Doi: 10.1016/j.compscitech.2011.07.011 [13] Ragoubi M, George B, Molina S, Bienaime D, Merlin A, Hiver JM, Dahoun A. Effect of corona discharge treatment on mechanical and thermal properties of composites based on miscanthus fibres and polylactic acid or polypropylene matrix. Composites Part A: Applied Science and Manufacturing. 2012; 43(4):675-685. Doi: 10.1016/j.compositesa.2011.12.025 [14] Bledzki AK, Mamun AA, Lucka-Gabor M, Gutowski VS. The effects of acetylation on properties of flax fibre and its polypropylene composites. Express Polymer Letters. 2008; 2(6):413-422. Doi: 10.3144/ expresspolymlett.2008.50 [15] Sghaier AEOB, Chaabouni Y, Msahli S, Sakli F. Morphological and crystalline characterization of NaOH and NaOCl treated Agave americana L. Fibre. Industrial Crops and Products. 2012; 36(1):257-266. Doi: 10.1016/j.indcrop.2011.09.012 [16] Sreekumar PA, Thomas SP, Saiter JM, Joseph K, Unnikrishnan G, Thomas S. Effect of fibre surface modification on the mechanical and water absorption characteristics of sisal/polyester composites fabricated by resin transfer moulding. Composites Part A: Applied Science and Manufacturing. 2009; 40(11):1777-1784. Doi: 10.1016/j.compositesa.2009.08.013

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NUR-E-ALAM M, et al. Enzyme-Accelerated Acid Hydrolysis of Untanned Proteinaceousâ&#x20AC;Ś TLR 3 (4) 2020 213-225.

Enzyme-Accelerated Acid Hydrolysis of Untanned Proteinaceous Wastes from Tanning Industry Md. NUR-E-ALAM1*, Nasifa AKTER1, Kanish FATEMA1, Md. Abul Kashem AZAD1, Shimul CHAKMA1,2, Md. Anwar Arfien KHAN3 Leather Research Institute, Bangladesh Council of Scientific and Industrial Research (BCSIR), Savar, Dhaka-1350, Bangladesh 2 Delhi Technological University, Delhi, 110042, India 3 Institute of Mining, Mineralogy and Metallugy, BCSIR, Joypurhat *nalam1980@yahoo.com 1

Original scientific article UDC 675.088:66.094.941:547.96 DOI: 10.31881/TLR.2020.13 Received 15 Jun 2020; Accepted 30 Aug 2020; Published Online 2 Oct 2020; Published 1 Dec 2020

ABSTRACT Traditionally, tanning industry has been producing considerable amounts of solid wastes, which raises serious concerns on account of their environmental impact. Out of these, untanned raw trimmings account for about 5-7% of the total quantity of raw materials processed. This waste could be a value-added cheap source of collagen, which has numerous industrial applications if properly and scientifically utilized. This research work deals with the utilization of raw trimmings of solid waste from tanneries in the process of enzymatic hydrolysis, performed by using acetic acid and protease, in order to obtain protein hydrolysate. The hydrolysis was carried out with varying acid concentrations, acid solutions, temperatures and times. The maximum obtained protein hydrolysate was about 88% at 1.5 M acid concentration, 4% enzyme ratio, and 60 Â°C. KEYWORDS Raw trimmings, Untanned proteinaceous solid wastes, Acid hydrolysis

INTRODUCTION Tanning raw hides and skins is one of the oldest processes of our ancestors. The search for methods of conserving hides and skins started in the early Stone Age, around 8,000 BCE. Around five thousand years later, the people of Egypt and Mesopotamia are said to have invented plant-based tanning, using the bark or gum of various trees [1]. The modern tanning process involves several steps in converting raw hides and skins into imputrescible substance and also generates large quantities of solid and liquid wastes. On average, the processing of one metric ton of rawhide produces 200 kg of tanned leather, 250 kg of non-tanned waste, 200 kg of tanned waste leather, and 50,000 kg of liquid waste (Table 1). About 50% of leather mass is lost during the tanning process [2].

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Table 1. Environmental input of leather processing, adapted from [3] Raw hide (1 ton) Leather

200 kg

Solid wastes / Byproducts Untanned wastes: Raw trimmings 120 kg Fleshing 70-230 kg Tanned wastes: Tanned splits 115 kg Trimmings + Shavings 100 kg Dyed / Finished: Buffing 2 kg Trimmings 32 kg

503 liquid effluent COD BOD Suspended solids Chromium Sulfide

235-250 kg 100 kg 150 kg 5-6 kg 10 kg

The tannery sector of Bangladesh is considered as the most polluting of industries, which is well established, and ranked fourth in terms of earning foreign exchange. The first tannery in Bangladesh was established at Narayanganj by R.P. Shaha in 1940. After that, the tannery industry was shifted to Hazaribagh, Dhaka [4]. At present all tanneries of Hazaribagh have been relocated to Savar Tannery Estate in order to protect the environment. As mentioned earlier, tanning processes generate huge amounts of liquid and solid wastes and if these wastes are not properly treated it will degrade the surrounding environment. Although tanneries have been moved to a new location, solid waste management is not properly maintained.

Raw trimmings of hides and skins

Solid waste in a nearby tanneryâ&#x20AC;&#x2122;s yard

Figure 1. Solid wastes from tanneries discarded without any treatment

Raw hides and skins are by-products of meat industry. Before pre-tanning operations, the hides and skins are trimmed (for the convenience of machine operations), which generates huge amounts of un-tanned proteinaceous solid wastes. These trimmings account for about 5-7% of the total quantity of raw materials processed. If these proteinaceous materials are not utilized appropriately, that will create hazardous pollution to the environment [5]. Leather solid wastes can be processed into valuable products such as glue, gelatin, artificial fibrous leathers, and collagen for various industrial uses. A number of authors have reported about various way of turning these wastes into valuable products. Enzymes, such as papain and neutrases [6], acids, such as phosphoric acid [7], sulphuric acid [8], propionic acid [9] and hydrochloric acid [10], and alkali, such as sodium hydroxide [11], magnesium oxide, calcium oxide [8] etc. are used as hydrolyzing agents in the treatment of solid waste generated by the tanning industry. Eco-friendly ultrasound technology can also be used to accelerate the 214 www.textile-leather.com

NUR-E-ALAM M, et al. Enzyme-Accelerated Acid Hydrolysis of Untanned Proteinaceous… TLR 3 (4) 2020 213-225.

hydrolyzing process [12]. In this research work, acetic acid (CH3COOH) and protease enzyme are used as hydrolyzing agents in the process of extracting the protein hydrolysate from untanned raw trimmings from tanneries in Bangladesh.

MATERIALS AND METHODS Material preparation NUR-E-ALAM M, et al. Enzyme-Accelerated Acid Hydrolysis of Untanned Proteinaceous… TLR 0 (0) 2020 00-00.

Raw trimmings from tanneries were collected from the Savar tannery estate, Savar, Dhaka. These were first washed with an excess amount of tap water in order to remove salt, dirt, dung, blood and other impurities. Hairs were removed by the liming process, using calcium oxide (CaO), and finally unhaired trimmings were Hairs were removed by the liming process, using calcium oxide (CaO), and finally unhaired trimmings were delimed by washing them several times with water. After that, they were air dried in the open. delimed by washing them several times with water. After that, they were air dried in the open. Then, the dried trimmings were cut into small pieces for hydrolysis. Acetic acid (CH3COOH), lime and protease Then, the dried trimmings were cut into small pieces for hydrolysis. Acetic acid (CH 3COOH), lime and protease enzyme were purchased from the local market. Glassware (pipettes, beakers, conical flasks, measuring enzyme were purchased from the local market. Glassware (pipettes, beakers, conical flasks, measuring cylincylinders, tubes waswas used was the product of Borosil/Ranken. A magnetichotplate, hotplate, aa stirrer, stirrer, Kjelders, test tubestest etc.) thatetc.) wasthat used the product of Borosil/Ranken. A magnetic Kjeldahl apparatus etc. used. were used. Acetic is commonlyused used as as aa souring in in thethe process of making dahl apparatus etc. were Acetic acidacid is commonly souringagent agent process of making vinegar, pickled vegetables and sauce, and as a raw material for spices, in diluted concentrations (4 to 8% vinegar, pickled vegetables and sauce, and as a raw material for spices, in diluted concentrations (4byto 8% mass). Forthis thisreason, reason, acetic was chosen as a hydrolysis agent inagent this study. by mass). For aceticacid acid was chosen as a hydrolysis in this study.

Experimental procedure Experimental procedure The study performed batch process of beakers equipped with stirrers stirringby dried raw dried The study was was performed ininaabatch processinina series a series of beakers equipped withby stirrers stirring trimmings and acetic acidacid in varying concentrations and at varying The detailed The detailed raw trimmings andusing using acetic in varying concentrations and temperatures. at varying temperatures. experimental methodologyisisgiven given in in Figure experimental methodology Figure2.2. Collecting raw material

Trimmings are collected from various tanning plants

Washing and dehairing

Washed with water several times and dehaired with lime

Deliming and cutting

Dehaired trimmings are delimed and cut into small fragments

Hydrolysis

Acid/enzyme hydrolysis

Figure 2. Experimental procedures of hydrolysis Figure 2. Experimental procedures of hydrolysis

Effect of acid concentration: Effect of acid concentration:– The effect of acid concentration on the protein hydrolysis can be examined by varying the concentration The effect of acid concentration on the protein hydrolysis can be examined by varying the concentration of of acid in the fixed acid solution at a fixed temperature. 50 gm of cleaned and dried raw trimmings was acid in the fixed acid solution at a fixed temperature. 50 gm of cleaned and dried raw trimmings was dissolved dissolved in 5 ml of 0.25M, 0.5M, 1.0M and 1.5M acetic acid solution. An extra 400 ml of distilled water in 5 mltoofeach 0.25M, 0.5M, and 1.5M was aceticset acid was added and the 1.0M temperature tosolution. 40 °C. An extra 400 ml of distilled water was added to each and the temperature was set to 40 °C.

Effect of acid solution: of acid solution: 50 gmEffect of cleaned and dried raw trimmings was put in the beaker with the optimal acid concentration and at a fixed temperature of 40 °C. www.textile-leather.com 215

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Effect of temperature: The examination of the effect of temperature on the protein hydrolysis was carried out with the optimal acid concentration and its solution. Effect of hydrolysis time: The examination of the effect of hydrolysis time (hour) was carried out with the optimal acid concentration, its solution and temperature. Enzymatic hydrolysis: The examination of the effect of enzyme concentration was carried out with best the optimal concentration, its solution, time and temperature.

Analysis The protein of the extracted hydrolysate was identified by the Biuret test and the protein concentration was determined by the Kjeldahl method in a Gerhardt digester (Germany). a) Biuret test The Biuret test is based on the ability of Cu(II) ions to form a violet-colored chelate complex with peptide bonds (-CONH- groups) in alkaline conditions. This test confirms the presence of proteins in the sample. In this test, 2 ml of extracted hydrolysate solution was taken in a dry test tube. 3 drops of 10% NaOH and 3-6 drops of 0.5% CuSO4 were added to the sample test tube [13]. b) Kjeldahl method The Kjeldahl method is used to determine the nitrogen content in organic and inorganic substances. For over a hundredNUR-E-ALAM years the Kjeldahl method has been for the determination of nitrogen a wide M, et al. Enzyme-Accelerated Acidused Hydrolysis of Untanned Proteinaceous… TLR 0 (0) in 2020 00-00.range of samples such as foods and drinks, meat, feeds, cereals and forages. It is also used for nitrogen determination in wastewaters, soils and other samples. The Kjeldahl method has three main steps (Figure 3): digestion, distillation, and titration. Digestion

Distillation

Titration

Organic nitrogen is converted into NH4+

NH3 is distilled

Nitrogen is determined

Figure 3. Main steps of Kjeldhal method Figure 3. Main steps of Kjeldhal method

Digestion Digestion The aim theofdigestion procedure is toisbreak all nitrogen bonds in the sample andand convert allall of of thethe organiTheofaim the digestion procedure to break all nitrogen bonds in the sample convert + + cally bonded nitrogen ammonium ions (NHions and water 1). During digestion, organically bondedinto nitrogen into ammonium (NH4 ), dioxide carbon dioxide and (equation water (equation i). During 4 ), carbon the organic material carbonizes, which canwhich be visualized by thebytransformation of the sample digestion, the organic material carbonizes, can be visualized the transformation of the sampleinto into black foam.black After that,After thethat, foam and and finally a clear thecompletion completion of chemical the chemical foam. thedecomposes foam decomposes finally a clearliquid liquidindicates indicates the of the reaction. For this purpose, the sample is mixed with sulfuric acid at temperatures between 350 and 380 °C. reaction. For this purpose, the sample is mixed with sulfuric acid at temperatures between 350 and 380 ºC. The higher the temperature, the faster the digestion can be obtained. The higher the temperature, the faster the digestion can be obtained.

The speed of the digestion can be greatly enhanced by the addition of salt and catalysts. Potassium sulfate 2SO4) is added in order to increase the boiling point of sulfuric acid, and catalysts (e.g. CuSO4) are added in 216 (Kwww.textile-leather.com

order to increase the speed and the efficiency of the digestion procedure [14]. Protein (-N) + H2SO4 = (NH4)2SO4 + CO2 + H20 -------------------------- (i)

NUR-E-ALAM M, et al. Enzyme-Accelerated Acid Hydrolysis of Untanned Proteinaceousâ&#x20AC;Ś TLR 3 (4) 2020 213-225.

The speed of the digestion can be greatly enhanced by the addition of salt and catalysts. Potassium sulfate (K2SO4) is added in order to increase the boiling point of sulfuric acid, and catalysts (e.g. CuSO4) are added in order to increase the speed and the efficiency of the digestion procedure [14]. Protein (-N) + H2SO4 = (NH4)2SO4 + CO2 + H20

(1)

Distillation In the distillation step, the ammonium ions (NH4+) are converted into ammonia (NH3) by introducing alkali (NaOH), as showed in equation (ii). (NH4)2SO4 + 2NaOH = 2 NH3 + Na2SO4 + 2 H20

(2)

NUR-E-ALAM M, et al. Enzyme-Accelerated Acid Hydrolysis of Untanned

The ammonia (NH3) is captured in absorbing solution like boric acid, sulfuric acid or hydrochloric acid into The concentration of BO captured ammonium ions is determined by either dire M, et al. Enzyme-Accelerated Acid Hydrolysis of Untanne the receiver vessel by means of steam distillation. BoricNUR-E-ALAM acid (H 3 3) of 2-4 % concentration is commonly used for capturing the ammonia, forming solvated ionammonia (equationisiii).present in the distillate with a color ch methodsammonium indicate the

The concentration of captured ammonium ions is determined by either dir unknown protein concentrations. (3) H3BO3 + NH3 + H20 = NH4+ + B(OH)4indicate the present in the distillate withby a color c Inmethods direct titration, boricammonia acid is is used for capturing ammonia formin

unknownwhich protein concentrations. complex, is neutralized by the addition of sulfuric acid, producing a cha Titration Inback direct titration, is used for or capturing ammonia by form The concentration of captured ammoniumInions is titration, determined byboric either titration back titration. sulfuric acidacid isdirect used for capturing ammonia. The residual su Both methods indicate the ammonia is present in theNH distillate with awith color change and allow for calculacomplex, which neutralized by the addition of sulfuric acid, producing a ch react with sodium hydroxide standard solution and the 3) isistitrated tion of unknown protein concentrations. back titration, sulfuric acid is used for capturing ammonia. The residual s byIndifference. In direct titration, boric acid is used for capturing ammonia by forming ammonia-borate (NH4+:H2BO3-) with NH titrated with sodium hydroxide standard solution and th 3) isproducing complex, which is neutralized by the additionreact of sulfuric acid, a change in color. Working procedureThe residual sulfuric acid (the excess that did by difference. In back titration, sulfuric acid is used for capturing ammonia. not react with NH3) is titrated with sodiumInhydroxide solution and the amount of ammonia is flask and dig this work, standard 0.5 g of hydrolysate sample was taken in a Kjeldahl calculated by difference. Working procedure sulfuric acid in the presence of a mixture of K2SO4 and CuSO4 in the ratio o

In this work, The 0.5 gformed of hydrolysate samplewere was titrated taken inwith a Kjeldahl acid solution. borate anions 0.05Mflask H2SOand 4 byd Working procedure sulfuric acid in to thenitrogen presence a mixture K2ml SOThe CuSO4 incontent the ratio 4ofand was converted inof the sample nitrogen an In this work, 0.5 g of hydrolysate sample was taken in a Kjeldahl flask and digested withof[13]. 15 concenCuSO 5:1 and distilled into a 4%0.05M H2SO4 by trated sulfuric acid in the presence of a mixture K2SOwere acidofsolution. The formed borate anions were titrated with 4 and 4 in the trimmings determined byratio the of following formulae [15]. SO4 bysample a direct[13]. titration boric acid solution. The formed borate anions were titrated with 0.05M Hin was converted to nitrogen Theprocenitrogen content a Calculation of nitrogen content 2(wthe n): dure which was converted to nitrogen in the sample [13]. The nitrogen content and the crude protein of trimmings were determined by the following formulae [15]. 2(đ?&#x2018;Łđ?&#x2018;Ł1 â&#x2C6;&#x2019;đ?&#x2018;Łđ?&#x2018;Ł 0 )đ?&#x2018;?đ?&#x2018;? đ?&#x2018;&#x20AC;đ?&#x2018;&#x20AC; the raw trimmings were determined by theđ?&#x2018;¤đ?&#x2018;¤following formulae [15]. ----------------- (iv), đ?&#x2018;&#x203A;đ?&#x2018;&#x203A; = đ?&#x2018;&#x161;đ?&#x2018;&#x161; Calculation of nitrogen content (wn): Calculation of nitrogen content (wn):

nitrogen content, in grams per kilogram, of the test sample where W n is )đ?&#x2018;?đ?&#x2018;? đ?&#x2018;&#x20AC;đ?&#x2018;&#x20AC; 2(đ?&#x2018;Łđ?&#x2018;Ł â&#x2C6;&#x2019;đ?&#x2018;Łđ?&#x2018;Łthe ----------------- (iv), đ?&#x2018;¤đ?&#x2018;¤đ?&#x2018;&#x203A;đ?&#x2018;&#x203A; = 1 0 (4) đ?&#x2018;&#x161;đ?&#x2018;&#x161; the sulfuric acid required for the determination; V0 is the volume, in milliliter

where Wn is the nitrogen content, in grams per kilogram, the test V1 is the volume, milliliters, of content, in grams perinper kilogram, thesulfuric test sampl where n isofthe the blankWtest; c isnitrogen the sample; concentration, in moles liter, ofof the acid the sulfuric acid required for the determination; V 0 is the volume, in milliliters, of the sulfuric acid required the sulfuric required for the determination; V0 is themvolume, in millilit molar mass, inacid grams per mole, of nitrogen (M 14 g/mol); is the mass, in gr for the blank test; c is the concentration, in moles per liter, of the sulfuric acid used for the titrations; M is the blank test; c is the concentration, in moles per liter, of the sulfuric ac the molar mass, in grams per mole, of nitrogen (M 14 g/mol); m is the mass, in grams, of the test portion. molar mass, grams per mole, Calculation of crude protein (wp): Calculation of in crude protein (wp): of nitrogen (M 14 g/mol); m is the mass, in g

------------------(v)

(5)

orCalculation of crude protein (wp):

= 6.25 đ?&#x2018;¤đ?&#x2018;¤đ?&#x2018;&#x203A;đ?&#x2018;&#x203A;% đ?&#x2018;&#x201D;đ?&#x2018;&#x201D;/đ?&#x2018;&#x2DC;đ?&#x2018;&#x2DC;đ?&#x2018;&#x201D;đ?&#x2018;&#x201D; ------------------(vi), ------------------(v) đ?&#x2018;¤đ?&#x2018;¤đ?&#x2018;¤đ?&#x2018;¤ đ?&#x2018;?đ?&#x2018;? đ?&#x2018;?đ?&#x2018;?= 0.625 đ?&#x2018;¤đ?&#x2018;¤đ?&#x2018;&#x203A;đ?&#x2018;&#x203A; www.textile-leather.com 217 or Wp is the crude protein content, expressed in grams per kilogram or in where

Calculation of crude protein (wp): đ?&#x2018;¤đ?&#x2018;¤ = 6.25 đ?&#x2018;¤đ?&#x2018;¤ đ?&#x2018;&#x201D;đ?&#x2018;&#x201D;/đ?&#x2018;&#x2DC;đ?&#x2018;&#x2DC;đ?&#x2018;&#x201D;đ?&#x2018;&#x201D;

------------------(v)

đ?&#x2018;?đ?&#x2018;? đ?&#x2018;&#x203A;đ?&#x2018;&#x203A; Calculation of crude Proteinaceousâ&#x20AC;Ś protein (wp): TLR 3 (4) 2020 213-225. NUR-E-ALAM M, et al. Enzyme-Accelerated Acid Hydrolysis of Untanned

đ?&#x2018;¤đ?&#x2018;¤đ?&#x2018;?đ?&#x2018;? = 6.25 đ?&#x2018;¤đ?&#x2018;¤đ?&#x2018;&#x203A;đ?&#x2018;&#x203A; đ?&#x2018;&#x201D;đ?&#x2018;&#x201D;/đ?&#x2018;&#x2DC;đ?&#x2018;&#x2DC;đ?&#x2018;&#x201D;đ?&#x2018;&#x201D; ------------------(v) đ?&#x2018;¤đ?&#x2018;¤đ?&#x2018;?đ?&#x2018;? = 0.625 đ?&#x2018;¤đ?&#x2018;¤đ?&#x2018;&#x203A;đ?&#x2018;&#x203A; % ------------------(vi), or where Wp is the protein expressed in grams per kilogram or in percentage đ?&#x2018;¤đ?&#x2018;¤đ?&#x2018;?đ?&#x2018;? crude = 0.625 đ?&#x2018;¤đ?&#x2018;¤đ?&#x2018;&#x203A;đ?&#x2018;&#x203A; %content, ------------------(vi), (6)

whereinWgrams crude protein expressed in grams per kilogram or i p is theper kilogram or content, in percentage. where Wp is the crude protein content, expressed Yield Yield The percentage of yield can be derived from the following equation [16]: The percentage of yield can be derived from the following equation [16]: Yield đ??´đ??´đ?&#x2018;?đ?&#x2018;?đ??´đ??´đ??´đ??´đ??´đ??´đ??´đ??´ đ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ??´đ??´đ?&#x2018;&#x2018;đ?&#x2018;&#x2018; đ?&#x2018;&#x2021;đ?&#x2018;&#x2021;â&#x201E;&#x17D;đ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;&#x2019;đ?&#x2018;&#x2019;đ?&#x2018;&#x2019;đ?&#x2018;&#x2019;đ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Ś đ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ??´đ??´đ??´đ??´

The (7) đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x201D;đ?&#x2018;&#x201D;đ?&#x2018;&#x192;đ?&#x2018;&#x192; đ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Ś = X 100 -------------(vii), percentage of yield can be derived from the following equation [16]: đ??´đ??´đ?&#x2018;?đ?&#x2018;?đ??´đ??´đ??´đ??´đ??´đ??´đ??´đ??´ đ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ??´đ??´đ?&#x2018;&#x2018;đ?&#x2018;&#x2018;

đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;&#x201D;đ?&#x2018;&#x201D;đ?&#x2018;&#x192;đ?&#x2018;&#x192; đ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;&#x192;đ?&#x2018;&#x192;đ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Ś = X 100 -------------- (vii), đ?&#x2018;&#x2021;đ?&#x2018;&#x2021;â&#x201E;&#x17D;đ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;&#x2019;đ?&#x2018;&#x2019;đ?&#x2018;&#x2019;đ?&#x2018;&#x2019;đ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Ś where actual yield is the amount of product obtained from hydrolysis and theđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ?&#x2018;Śđ??´đ??´đ??´đ??´ theoretical yield is 68% [2].

RESULTS AND DISCUSSION

FTIR analysis The FTIR spectrum of the protein hydrolysate obtained from untanned raw trimmings of solid waste from tanneries in the region 500-4000 cm-1 is shown in Figure 4. Wavelength is in the 3600â&#x20AC;&#x201C;3200 cm-1 region, resulting from superimposed OH and NH3+ stretching bands. Signals at 1645 cm-1 and 1541 cm-1 correspond to the carbonyl group (C=O) and Nâ&#x20AC;&#x201C;H, which is the evidence of protein structure [17].

Figure 4. Effect of acetic concentration on protein hydrolysis

Biuret and Kjeldahl methods Figure 5 shows the change in color of the extracted hydrolysate from grey (a) to purple (b) after the addition of biuret reagent. This change in color represents the presence of proteins in the hydrolysate extracted from raw trimmings.

(a)

(b)

Figure 5. Biuret test (a) before addition of biuret reagent, (b) after addition of biuret reagent

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NUR-E-ALAM M, et al. Enzyme-Accelerated Acid Hydrolysis of Untanned Proteinaceousâ&#x20AC;Ś TLR 3 (4) 2020 213-225.

Protein hydrolysis of raw trimmings from tanneries by acetic acid was performed with the parameters of acid concentration, acid concentration solution, temperature, and hydrolysis time. Protein concentrations (crude protein) of the extracted hydrolysates were determined by the Kjeldahl method.

Effect of acetic acid concentration on protein hydrolysate The effect of acetic acid concentration (M) on protein hydrolysis of raw trimmings from tanneries was carried out by hydrolyzing 50 gm of raw trimmings with various acid concentrations (M) with fixed acid solution (5ml) and at a fixed temperature (40 Â°C). It is shown in Figure 6 that the percentage of protein was increasing with the increase in the concentration of acetic acid from 0.25 to 1.5 molar (M). Since acetic acid is a weak acid and used as a souring agent in vinegar, pickled vegetables etc. in diluted concentrations, it is taken as a hydrolyzing agent in this study. As analytical grade acetic was used in this research, the concentration of acid was not more than 1.5M. The maximum of about 32% protein hydrolysate was extracted from 1.5M acid concentration and the yield was about 23%.

Figure 6. Effect of acetic concentration on protein hydrolysis

Crude protein calculation Table 2. Volume of H2SO4 (ml) required for crude protein determination by titration and yield for effect of acetic acid concentration on hydrolysis Volume of 0.05M H2SO4 (ml)

N content (g/kg), Equation (iv)

Crude protein (%), Equation (vi)

Crude protein (g/50gm)

Yield (%), Equation (vii)

Initial

Final

Diff.

Average (ml)

Blank

0.25 a

11.8

11.6

32.5

20.3

10.2

14.9

0.25 b

23.4

11.4

0.5 a

13.8

38.6

24.2

12.1

17.8

16.8

29.4

14.7

21.6

18.4

51.5

32.2

16.1

23.7

Sample

0.5 b

13.6

1.0 a

36.6

16.6

1.0 b

1.5 a

43.6

18.6

1.5 b

18.2

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NUR-E-ALAM M, et al. Enzyme-Accelerated Acid Hydrolysis of Untanned Proteinaceousâ&#x20AC;Ś TLR 3 (4) 2020 213-225.

Effect of concentration solution on protein hydrolysate The effect of acetic acid concentration solution (ml) on protein hydrolysis of raw trimmings from tanneries is shown in Figure 7. Solution of 5 ml, 10 ml, 15 ml and 20 ml of 1.5M acetic acid were taken for each 50 gm of raw trimmings. From Figure 7, it can be observed that the percentage of yield was increasing with the increase in acid solution and the maximum crude protein percentage was found with 20 ml solution of 1.5M acetic acid and its yield was about 34%.

Figure 7. Effect of acetic acid solution on protein hydrolysis

Effect of temperature on protein hydrolysate Figure 8 shows the effect of temperature on hydrolysis of tannery raw trimmings using best acid concentration (1.5M) and concentration solution (20ml) with temperature variation from 40 to 1100 C. On heating, trimmings, mainly composed of collagen, are disintegrated and dissolved very quickly. The maximum percentage of protein hydrolysate was obtained about 58 at temperature 800 C and yield was about 43%. Temperature above this, the denaturation of protein was occurred and hence yield declined. As raw trimmings are biological materials, the temperature should not increase to high due to avoiding denature of protein.

Figure 8. Effect of temperature on protein hydrolysis

Effect of hydrolysis time on protein hydrolysate Figure 9 shows the effect of hydrolysis time (hour) on hydrolysis with 1.5M acetic concentration, 20 ml acid solution and at 80 Â°C temperature. About 71% of protein hydrolysate was obtained after 14 hours of hydrolysis and the yield was about 52%. After that the trend of increase was negligible. 220 www.textile-leather.com

NUR-E-ALAM M, et al. Enzyme-Accelerated Acid Hydrolysis of Untanned Proteinaceousâ&#x20AC;Ś TLR 3 (4) 2020 213-225.

Figure 9. Effect of hydrolysis time on protein hydrolysate

Effect of enzyme concentration (%) on hydrolysis 10 ml solution of 1 to 6% enzyme on the basis of sample weight was prepared for hydrolysis at 1.5 M acetic acid concentration as shown in Figure 10. Other operating parameters, temperature and hydrolysis time, were 80 Â°C and 4 hours respectively. Among the various enzyme ratios, about 55% protein was extracted from 4% ratio of enzyme and the yield was about 41%. After that, the percentages were negligible.

Figure 10. Effect of enzyme concentration (%) on hydrolysis

Effect of enzyme solution (ml) on hydrolysis Figure 11 shows the effect of enzyme solution on hydrolysis. After the addition of 20 ml enzyme solution, the percentage of protein, which was about 63%, was not increased significantly and the yield was about 46%.

Figure 11. Effect of enzyme solution (ml) on hydrolysis

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Effect of heating time on enzymatic hydrolysis Heating time in enzymatic hydrolysis significantly increases the protein extraction, as shown in Figure 12. The hydrolysis was conducted with the temperature not above 50-60 °C due to enzyme activity in the 1st stage and the final hour used for solidification of the digested sample at 80 °C in the 2nd stage. About 22% of protein hydrolysate was obtained by increasing hydrolysis duration from 4 hours to 6 hours with 1.5 M acetic acid concentration and 20 ml of its solution. The maximum of 88% of protein hydrolysate was obtained after 12 hours of hydrolysis and the yield was about 65%.

Figure 12. Effect of heating time on enzymatic hydrolysis Table 3. Crude protein analysis by Kjeldhal method (acetic acid hydrolysis), sample weight 50 gm Conc. (M)

Solution (ml)

Temp (°C)

Time (h)

Crude protein (%)

Crude protein (g/50gm)

Yield (%)

0.25

20.3

10.2

14.9

0.5

24.2

12.1

17.8

1.0

29.4

14.7

21.6

1.5

32.2

16.1

23.7

1.5

32.4

16.2

23.8

1.5

39.2

19.6

28.8

1.5

44.5

22.2

32.7

1.5

46.2

23.1

33.9

1.5

46.4

23.2

34.1

1.5

52.2

26.1

38.4

1.5

58.3

29.1

42.9

1.5

100

55.1

27.6

40.5

1.5

110

52.2

26.1

38.4

1.5

58.6

29.3

43.1

1.5

60.2

30.1

44.3

1.5

63.5

31.8

46.7

1.5

67.2

33.6

49.4

1.5

71.2

35.6

52.4

1.5

72.3

36.1

53.2

1.5

72.5

36.2

53.3

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NUR-E-ALAM M, et al. Enzyme-Accelerated Acid Hydrolysis of Untanned Proteinaceous… TLR 3 (4) 2020 213-225.

Table 4. Crude protein analysis by Kjeldhal method (acid-enzyme hydrolysis), sample weight 50 gm Acid conc. (M)

Enzyme ratio (%)

Enzyme Solution (ml)

1st stage Temp (°C)

1st stage time (h)

2nd stage Temp (°C)

2nd stage time (h)

Crude protein (%)

Crude protein (g/50gm)

Yield (%)

1.5

50-60

45.7

22.8

33.6

1.5

50-60

48.3

24.2

35.5

1.5

50-60

53.2

26.6

39.1

1.5

50-60

55.3

27.7

40.7

1.5

50-60

55.1

27.6

40.5

1.5

50-60

55.1

27.6

40.5

1.5

50-60

48.3

24.2

35.5

1.5

50-60

55.3

27.7

40.7

1.5

50-60

61.6

30.8

45.3

1.5

50-60

31.5

46.3

1.5

50-60

63.2

31.6

46.5

1.5

50-60

63.4

31.7

46.6

1.5

50-60

63.5

31.8

46.7

1.5

50-60

85.2

42.6

62.7

1.5

50-60

88.2

44.1

64.9

1.5

50-60

88.2

44.1

64.9

1.5

50-60

88.4

44.2

64.9

Some pictures of protein determination by Kjeldhal method are shown in Figure 13 and 14.

(a)

(b)

Figure 13. Digestion of raw trimmings (a) at the start of digestion and (b) at the end of digestion

(a)

(b)

(c)

(d)

Figure 14. Distillation of the digested sample: (a) adding NaOH to the digested sample, (b) boric acid with the methyl red indicator, (c) capturing the NH3 in boric acid (yellowish color), (d) boric acid solution before and after capturing NH3

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Raw trimmings hydrolysis and the final product are shown in Figure 15.

(a)

(b)

Figure 15. (a) raw trimmings hydrolysis and (b) final product

APPLICATIONS OF RAW TRIMMIMGS The collagen / gelatin extracted from untanned raw trimmings of hides and skins has huge application potential in the field of packaging, biomedicine and cosmetics according to recent studies. The gelatin extracted by acetic acid from raw trimmings was blended with polyvinyl alcohol (PVA) and used to prepare a kind of biodegradable packing material. Here, PVA was used to reduce high water-solubility of gelatin. Collagen burn-healing membrane was prepared from the collagen extracted from pig skin by enzymatic hydrolysis. Hybrid films can be prepared by using collagen extracted from the trimmed skin by acetic acid and then blending with starch/soy protein [18]. Collagen can bind large fat quantities as an emulsifier in meat products. Gelatin is playing a major role in stabilizing ice-cream and other frozen foods. The most common use of gelatin in pharmaceutical industry is covering the outer layer of capsules [19]. Tissue adhesive, vascular grafts, aortic heart valves, drug delivery matrices, wound dressing, and tissue engineering scaffold can be made from collagenous materials derived from leather trimmings [3].

CONCLUSION Solid wastes generated by the tanning industry pose a great threat to the environment if not properly managed. Untanned raw trimmings do not get any treatment in the tanning process and they can be used as a cheap source of collagen, which has various industrial applications. In this study, the addition of enzyme to the process of hydrolysis with acetic acid accelerated the extraction of protein hydrolysate when compared to hydrolysis with acetic acid alone. About 88% of protein hydrolysate was obtained from enzyme-assisted acid hydrolysis of raw trimmings from tanneries. Acknowledgments The authors acknowledge the financial support provided by the Leather Research Institute, Bangladesh Council of Scientific and Industrial Research (BCSIR) under Research and development (R&D) activities.

REFERENCES [1] Barbe J. The History of Leather Tanning [Internet]. Maharam. Available from: https://www.maharam. com/stories/barbe_the-history-of-leather-tanning. [2] Bajza Z, Vrcek V. Thermal and enzymatic recovering of proteins from untanned leather waste. Waste Management. 2001; 21(1):79â&#x20AC;&#x201C;84. Doi: 10.1016/s0956-053x(00)00039-8 224 www.textile-leather.com

NUR-E-ALAM M, et al. Enzyme-Accelerated Acid Hydrolysis of Untanned Proteinaceous… TLR 3 (4) 2020 213-225.

[3] Sundar VJ, Gnanamani A, Muralidharan C, Chandrababu NK, Mandal AB. Recovery and utilization of proteinaceous wastes of leather making: A review. Reviews in Environmental Science and Biotechnology. 2011; 10:151–163. Doi: 10.1007/s11157-010-9223-6 [4] Nur-E-Alam M, Abu Sayid Mia M, Ahmad F, Mafizur Rahman M. Adsorption of chromium (Cr) from tannery wastewater using low-cost spent tea leaves adsorbent. Applied Water Science. 2018; 8:129. Doi: 10.1007/s13201-018-0774-y [5] Kanagaraj J, Velappan KC, Babu NC, Sadulla S. Solid wastes generation in the leather industry and its utilization for cleaner environment. Cheminform. 2006; 37(49). Doi: 10.1002/chin.200649273 [6] Damrongsakkul S, Ratanathammapan K, Komolpis K, Tanthapanichakoon W. Enzymatic hydrolysis of rawhide using papain and neutrase. Journal of Industrial and Engineering Chemistry. 2008; 14(2):202206. Doi: 10.1016/j.jiec.2007.09.010 [7] Chakarska I, Goshev I, Idakieva K, Apostolov G. Isolation and characterization of phosphoric acidsoluble collagen from leather wastes of pig breed Bulgarian white. Journal of the Society of Leather Technologists and Chemists. 2006; 90(6):260–263. [8] Khatoon M, Kashif SR, Saad S, Umer Z, Rasheed A. Extraction of amino acids and proteins from chrome leather waste. Journal of Waste Recycling. 2017; 2:1-4. [9] Masilamani D, Madhan B, Shanmugam G, Palanivel S, Narayan B. Extraction of collagen from raw trimming wastes of tannery: A waste to wealth approach. Journal of Cleaner Production. 2016; 113:338– 344. Doi: 10.1016/j.jclepro.2015.11.087 [10] Simeonova LS, Dalev PG. Utilization of a leather industry waste. Waste Management. 1996; 16(8):765– 769. Doi: 10.1016/S0956-053X(97)00020-2 [11] Sathish M, Madhan B, Rao JR. Leather solid waste: An eco-benign raw material for leather chemical preparation – A circular economy example. Waste Management. 2019; 87:357–367. Doi: 10.1016/j. wasman.2019.02.026 [12] Jian S, Wenyi T, Wuyong C. Ultrasound-accelerated enzymatic hydrolysis of solid leather waste. Journal of Cleaner Production. 2008; 16(5):591–597. Doi: 10.1016/j.jclepro.2006.12.005 [13] Chang SK, Zhang Y. Protein Analysis. In: Nieise S, editor. Food Analysis. Food Science Text Series. Springer International Publishing, 2017. p. 315–331. [14] PanReac AppliChem. Nitrogen Determination by Kjeldahl Method. Available from: https://www. itwreagents.com/uploads/20180114/A173_EN.pdf [15] ISO 5983-1:2005. Animal Feeding Stuffs-Determination of Nitrogen Content and Calculation of Crude Protein Content-Part 1: Kjeldahl Method. 2005. Available from: https://www.iso.org/standard/39145. html [16] Zhao W, Yang R, Zhang Y, Wu L. Sustainable and practical utilization of feather keratin by an innovative physicochemical pretreatment: High density steam flash-explosion. Green Chemistry. 2012; 14:3352– 3360. Doi: 10.1039/C2GC36243K [17] Oliveira LCA, Goncalves M, Oliveira DQL, Guerreiro M, Guilherme LRG, Dallago RM. Solid waste from leather industry as adsorbent of organic dyes in aqueous-medium. Journal of Hazardous Materials. 2007; 141(1):344–347. Doi: 10.1016/j.jhazmat.2006.06.111 [18] Li Y, Guo R, Lu W, Zhu D. Research progress on resource utilization of leather solid waste. Journal of Leather Science and Engineering. 2019; 1:1–17. Doi: 10.1186/s42825-019-0008-6 [19] Jayathilakan K, Sultana K, Radhakrishna K, Bawa AS. Utilization of byproducts and waste materials from meat, poultry and fish processing industries: A review. Journal of Food Science and Technology. 2012; 49:278–293. Doi: 10.1007/s13197-011-0290-7 www.textile-leather.com 225

NURUNNABI M, et al. Study on Comparative Analysis of Basic Woven Fabrics â&#x20AC;Ś TLR 3 (4) 2020 226-239.

Study on Comparative Analysis of Basic Woven Fabrics Produced in Air-Jet Loom and Determining Structure for Optimum Mechanical Properties and Production Md. NURUNNABI*, Jubayer Ibn HARIS, Fairooz Raisa MRIDULA Department of Textile Engineering, National Institute of Textile Engineering and Research (NITER), Nayarhat, Savar, Dhaka 1350, Bangladesh *nurunnabi@niter.edu.bd Original scientific article UDC 677.074:677.014 DOI: 10.31881/TLR.2020.06 Received 18 Apr 2020; Accepted 12 Oct 2020; Published Online 31 October 2020; Published 1 Dec 2020

ABSTRACT This analysis was directed at dissecting the impact of the structure of the fabric on different properties of the fabric, for example tear strength, tensile strength, shrinkage, elongation, skewness, and so on. The work demonstrated how various structures of the fabric influence these properties. Fabrics with a fundamental woven structure, namely plain, twill, satin and a couple of their subsidiaries, were produced to explore the influence of the structure on different properties of the fabric. The examination built up an approach to gauge the mechanical conduct of the fabric dependent on its structure. The exploration accentuated the structure and detail of the fabric to decide the underlying driver of the change in the mechanical conduct. The properties of the fabric, such as tear strength, tensile strength, elongation, shrinkage and skewness, were extraordinarily affected by the structure of the fabric. It likewise demonstrated to having more noteworthy mechanical properties for firmly interwoven structures, such as plain and twill. The analysis led to the conclusion that the plain structure has the best mechanical properties among different structures. KEYWORDS Air-jet loom, Woven fabric, Mechanical properties, Tear strength, Tensile strength, Shrinkage

INTRODUCTION Woven fabric is any textile formed by the interlacement of many warp and weft yarns at right angles to one another. The most versatile structure of all fabrics is the woven fabric which is created by the interlacement of two sets of yarn, where one set is called the warp yarn, which is longitudinal, and the other is weft yarn, which is transverse. It is the most advanced and refined fabric available, with various designs. It is conceivable to create different designs, like plain, twill, satin, etc. by varying the interlacement. These basic structures have numerous derivatives and designs. These variations of the designs have some effect on the mechanical properties of woven fabrics [1]. Virtually all types of textile fibres and threads can be used to make woven fabric. In antiquated occasions, woven fabrics were produced utilizing handlooms and the activity was completely manual. Nowadays there are numerous sorts of modern looms developed

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which are completely programmed and able to create the most extreme measure of fabric in the briefest conceivable time. Air-jet is a cutting-edge loom which is boundlessly used to produce woven fabrics throughout the whole textile industry. It is a very popular loom due to its higher efficiency, lower power consumption and maintenance cost than other looms present in the market [2]. In a typical air-jet loom the picking process into the warp shed is done by compressed air, rather than any projectile or shuttle. A special type of reed called “profile reed” [3] is used to help pick the insertion. Upon picking the insertion, the weft yarn goes through the main air nozzle which provides the initial acceleration of the weft yarn [4], and the profiled reed guides the weft yarn onto the other side of the loom for a successful pick insertion. From the focal air tank an adequate amount of air pressure is delivered, which changes into kinetic energy in the nozzle and conveys the weft yarn in the diversely formed air channels [5]. The purpose of this study is to find an optimum structure of the woven fabric produced in the air-jet loom. There are many structures of the woven fabric available now; however, there hasn’t been much concern about the suitability of the structure of the fabric produced in the air-jet loom [6]. This study shows the mechanical properties of different fabrics according to their structure and analyses the change in those properties. The findings of this study will be of benefit to the woven fabric industries in regard to the efficient production of high-quality fabrics. Woven fabric is the most sophisticated and aristocratic fabric, available in numerous variations in design. Due to the variation in the interlacement, different structures can be produced, such as plain, twill, satin, etc. Results from a research paper “Effect of Fabric Structure on the Mechanical Properties of Woven Fabrics” [7] show that these variations of structural designs tend to have some effect on the mechanical properties of the woven fabric. For textile fabric, it is described as a result of the material’s resistance to the activity of external forces causing the change of shape [8]. The test results from a research journal from Mehdi Kamali Dolatabadi “Anisotropy in tensile properties of plain weave fabric–Part I: The meso-scale model” shows that in design engineering, mechanical properties play a vital role in resisting the permanent deformation under applied stress and subsequent use [9]. From all of these journals the following results were concluded: a) The strength of a plain-weave fabric is higher than that of a twill-weave fabric. b) Warp way plain is stronger than twill and, also, weft way plain is stronger than weft way twill. c) Warp-wise tensile strength of the plain weave is higher than the twill weave. Similarly, weft-wise tensile strength of the plain weave is also higher than that of the twill weave [8]. d) The value of COF (Crossing Over Factor) is higher in the plain than in the twill and satin. Oppositely, the value of FYF (Floating Yarn Factor) is higher in the satin than in the twill and plain. e) Tearing strength is higher in the 2/2 twill than in the 3/1 twill due to the double yarn being inserted as weft. f) The greater the difference in warp and weft yarn density, the greater the difference in tearing resistance [10].

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MATERIALS AND METHODS Raw materials The woven fabrics produced in the air-jet loom are as follows: Table 1. Air-jet loom fabric sample No.

Sample Name

Construction ((EPI × PPI)/ (warp count × weft count))

Sample 1 (Dobby)

128×60/30×16+70D

Sample 2 (Dobby)

154×82/40×20+40D

Sample 3 (Canvas)

124×60/20+20D×14

Sample 4 (Oxford Canvas)

90×34/10+10D×6

Sample 5 (Cotton Sheeting)

60×60/20×20

Sample 6 (Herringbone)

165×85/20×10+70D

Sample 7 (2/2 S Twill)

206×98/40×30+40D

Sample 8 (2/1 S Twill)

168×68/30×30+40D

Sample 9 (Herringbone)

130×54/30×30+40D

10.

Sample 10 (Satin)

188×74/30×20+40D

Dobby Dobby fabric is a derivative of the plain fabric. It differs from other plain derivatives by construction (which is generally similar to (128×60/30×16+70D)). This fabric is generally small, with frequently repeated wovenin designs and textured.

Canvas Canvas is also a derivative of the plain-woven fabric. It is extremely durable and used for making marquees, sails, tents, shelters, backpacks and canvasses as a support for oil painting etc.

Oxford Canvas Oxford canvas is another derivative of the plain-woven fabric. It is suitable for cushion covers, curtains, and other more rugged fabric needs.

Cotton Sheeting Cotton sheeting is a lightweight, plain fabric used in costume making, stagecraft, garments manufacturing, home décor etc.

Herringbone This is a V-shaped twill weaving pattern. It is called like that because it looks similar to the skeleton of the herringbone fish.

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2/2 S Twill This is another twill pattern with the repeat of 2 warp up and 2 warp down. The structure runs in the shape of the letter ‘S’. Twill is a diagonal rib pattern.

2/1 S Twill This is another twill pattern with the repeat of 2 warp up and 1 warp down. The structure runs in the shape of the letter ‘S’. NURUNNBI M, et al. Study on Comparative Analysis of Basic Woven Fabrics … TLR 0 (0) 2020 00-00.

Satin Satin is a warp face weave and it has a rather dull texture on the back. The number of floats in satin is also 1) Tear Strength (ISO 139371) high. This test method is known as the ballistic pendulum (Elmendorf) method for the

Machine

determination of tear force of textile fabrics. The specimen is fastened in the clams and the

tear is(main started by cutting a slit in the air-jet specimen Shower type/multi-jet nozzle and relay nozzles) loombetween the clamps. The pendulum is then released and the specimen is torn completely as the moving jaw moves from the fixed one. Brand name: Picanol OptiMax The tear force is measured.

Testing methods

2) Tensile Strength (ISO 139341)

The research was This conducted by testing the above-mentioned specimen according the followingforce procedure: test method specifies a procedure for the determination ofto the maximum of textile 1) Tear Strength (ISO 139371) fabrics known as the grab test. A fabric test specimen, gripped in its centre part by jaws of This test method is known as the ballistic pendulum (Elmendorf) method for the determination of tear specified dimensions, is extended at a constant rate until it ruptures. The maximum force is force of textile fabrics. The specimen is fastened in the clams and the tear is started by cutting a slit in the specimenrecorded. between the clamps. The pendulum is then released and the specimen is torn completely as the moving jaw moves from the fixed one. The tear force is measured. 3) Skewness (ISO 163222) 2) Tensile Strength (ISO 139341) Skewness is the displacement of filling yarns from an imaginary line perpendicular to the This test method specifies a procedure for the determination of the maximum force of textile fabrics fabric in an angular form. It disturbs the grain line of the garment patterns and causes known as the grab test. A fabric test specimen, gripped in its centre part by jaws of specified dimensions, functioning the final garment. To measure the skewness, a steel is extended atdiscomfort a constantand rateimproper until it ruptures. Theofmaximum force is recorded. may be used. The straight edge of the steel tape is placed across the fabric width to 3) Skewness (ISOtape 163222) Skewness is the displacement of filling yarnsthe from imaginary perpendicular to the fabric of in fabric an measure the distance between twoanpoints whereline a selected weft yarn or course angular form. It disturbs the grain line of the garment patterns and causes discomfort and improper meets the two edges or selvedges. Then the straight line of distortion of the marked filling functioning of the final garment. To measure the skewness, a steel tape may be used. The straight edge fromisa placed line perpendicular to the width selvedge measured. of the steel tape across the fabric to is measure the distance between the two points AB

(1) (1)

Skew (%) = 100 × BC ,

where a selected weft yarn or course of fabric meets the two edges or selvedges. Then the straight line where AB is the fabric width perpendicular to the selvedge; and BC is the skew depth. of distortion of the marked filling from a line perpendicular to the selvedge is measured. Shrinkage Measurement (AATCC where AB4)is the fabric width perpendicular to 135) the selvedge; and BC is the skew depth. 4) Shrinkage Measurement 135)problem in fabric production where fabric becomes smaller, usually Shrinkage is(AATCC a common Shrinkage is aafter common problem in fabric production where smaller, usually the the process of laundering. This problem is afabric resultbecomes of high tension during theafter production process of laundering. This problem is a result of high tension during the production of fabric generally. of fabric generally. Normally, shrinkage is measured in percentages (%) and the standard acceptable shrinkage is less than 5%, but it can be changed at the request of the buyer.

www.textile-leather.com 229 Fabric shrinkage (%) =

Length before washing − Length after washing × 100 Length before washing

4) Shrinkage Measurement (AATCC 135) Shrinkage is a common problem in fabric production where fabric becomes smaller, usually NURUNNABI al. Studyof onlaundering. ComparativeThis Analysis of Basic Fabrics TLR 3 (4) 2020 the 226-239. afterM, theetprocess problem is a Woven result of high …tension during production

of fabric generally. Normally, shrinkage is measured in percentages (%) and the standard

NURUNNABI M, et al. Study on Comparative Analysis of Basic Woven Fabrics … TLR 0 (0) 2020 00-00.

Normally, shrinkage is measured in percentages the standard acceptable acceptable shrinkage is less than 5%, but it can(%) beand changed at the request of theshrinkage buyer. is less than 5%, but it can be changed at the request of the buyer.

Average breaking strength and elongation or the increase in the fabric length under force to Length before washing − Length after washing Fabric shrinkage (%) = 100 NURUNNABI al. Study on Comparative Analysis of Basic Fabrics … TLR 0 (0) × 2020 the point M, of et rupture expressed in percentages (%) isWoven the breaking strength and00-00. elongation Length before washing

percentage of the fabric. Greater breaking strength and the elongation of fabric means 5) Elongation Measurement (ASTM D 5034) 5) Elongation Measurement 5034) breaking strength andmore elongation thestill increase in the fabric length under force to betterAverage fabric quality as(ASTM it canDbear stretchorand not tear. This is basically the ratio Average breaking strength and elongation or the increase in the fabric length under force to the point of thelength point of breaking rupture expressed in percentages (%) is the breaking strength elongation between at point andbreaking length ofstrength the fabric when produced from theand rupture expressed in percentages (%) is the and elongation percentage ofloom. the fabric. E−L Greater breaking strength elongation ofbreaking fabric means better fabric quality as it can bear more percentage ofand thethe fabric. Greater means Breaking elongation (%) = ×strength 100 , and the elongation of fabric(2) L stretch and still notfabric tear. This is basically ratio between at breaking lengththe of the better quality as it canthe bear more stretchlength and still not tear. point This isand basically ratio fabric when produced from the loom. between length at breaking point and length of the fabric when produced from the loom. where E is the extended length of the specimen after applying force; and L is the initial length E−L (2) Breaking elongation (%) = × 100 , (2) L of the specimen. 6) where E is the extended length of the specimen after applying force; and L is the initial length of the E is the extended length of the specimen after applying force; and L is the initial length RESULTS AND where DISCUSSION specimen. of the specimen. The above-mentioned tests were done on fabric specimens and the results are discussed as follows:

RESULTS AND DISCUSSION

Plain-weave structure: the samples 1-5, which represent the plain-weave structure, were taken and RESULTS AND DISCUSSION The above-mentioned tests were on fabric specimensThe andresults the results are discussed tested in order to compare theirdone mechanical properties. are shown below. as follows: Plain-weave structure: the samples the plain-weave structure, were taken and tested The above-mentioned tests 1-5, werewhich donerepresent on fabric specimens and the results are discussed as follows: Tear strength: the tear strength of the plain weave samples 1-5 was analysed and the results are in order Plain-weave to compare their mechanical properties. The results are shown below. structure, were taken and structure: the samples 1-5, which represent the plain-weave shown below. Tear strength: the tear strength of the plain weave samples 1-5 was analysed and the results are shown below. tested in order to compare their mechanical properties. The results are shown below. Tear strength: the tear strength of the plain weave samples 1-5 was analysed and the results are Fabric structure vs tear strength of plain structures

shown below. 50

30 20

Tear strength, N

10 0

Warp

Fabric structure vs tear strength of plain structures

24,5

Warp 19,57

40 18,6 17,8

30 11

20 24,5

17,8 Sample 2 Dobby

11 Sample 1 Dobby

Sample 3 Canvas

Sample 4 Oxford Canvas

Weft

16,45

19,57

18,6

Sample 1 Dobby

Weft

Sample 5 Cotton Sheeting 16,45

Fabric Structure Sample 2 Dobby

Sample 3 Canvas

Sample 4 Oxford

Figure various plain plainfabric fabricstructures structures Figure1.1.Tear Tearstrength strength of of various Canvas

Sample 5 Cotton Sheeting

Fabric Structure

Figure 1 shows that Sample 3, canvas fabric, has the amount of tearofstrength both inboth warpinand weft Figure 1 shows that Sample 3, canvas fabric, hashighest the highest amount tear strength warp Figure 1. Tear strength of various structures direction. The other plain-weave structures show much lesserplain tearfabric strength. This is because of the warp and weft direction. The other plain-weave structures show much lesser tear strength. This is because and weft yarn density of the fabric. This test results are parallel to the findings of Krook and Fox [11]. They of the Figure warp and weft density of canvas the fabric. This test results areamount parallel thestrength findings of Krook discovered that tearyarn strength of 3, the fabric increases as density of longitudinal yarn is both decreased. 1the shows that Sample fabric, has thethe highest oftotear in warp

and Fox discovered that the tear structures strength of themuch fabriclesser increases as the This density of and[11]. weft They direction. The other plain-weave show tear strength. is because of the warp and weft yarn density of the fabric. This test results are parallel to the findings of Krook 230 www.textile-leather.com and Fox [11]. They discovered that the tear strength of the fabric increases as the density of

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NURUNNABI M, et al. Study on Comparative Analysis of Basic Woven Fabrics … TLR 3 (4) 2020 226-239.

longitudinal yarn is decreased. Looking at Table 1, we can see that the canvas fabric has much at lower EPI1,and otherthe derivatives. Thathas is why it has much Looking Table we PPI canthan see that canvas fabric much lower EPI greater and PPItear thanstrength. other derivatives. Tensile the greater tensile tear strength of the plain weave samples 1-5 was analysed and the results That is whyStrength: it has much strength. Tensile Strength: the tensile strength of the plain weave samples 1-5 was analysed and the results are shown are shown below. below. Fabric structure vs tensile strength of plain structures 800

660

Tensile Strength, N

700 600 500

529

456

367,86

338

400

382

300 200 100 0

378

303,81

262,4 180

Sample 1

Warp

Sample 2

Sample 3

Sample 4

Weft

Sample 5

Fabric Structure

Figure structures Figure2.2.Tensile Tensilestrength strengthof ofvarious various plain plain weave weave structures

Figure 2 shows that the canvas fabric (Sample 3) has much greater tensile strength than the other derivatives Figure 2 shows that the canvas fabric (Sample 3) has much greater tensile strength than the other of the plain structure. This happened due to the fact that the canvas fabric had much greater warp way and derivatives of the plaindirectly structure. This happened due totensile the fact that the canvas much weft way strength, which contributed to the greater strength than in thefabric other had fabrics [12]. Skewness: theM, skewness percentage of the Analysis plain weave samples 1-5 was analysed and the00-00. results shown greater warp way weft way strength, which contributed greater tensile are strength NURUNNABI et al. and Study on Comparative of directly Basic Woven Fabrics … to TLRthe 0 (0) 2020 below. than in the other fabrics [12].

Skewness: the skewness percentage of the plain weave samples 1-5 was analysed and the results are Fabric structure vs skewness of plain structures

shown below.

Skewness, %

3,00%

2,40%

2,50% 1,80%

2,00%

1,60%

1,50% 1,00% 0,50% 0,00%

0,80%

Fabric Skewness %

0,40%

Sample 1

Sample 2

Sample 3

Sample 4

Sample 5

Fabric Structure

Figure (%) of of various variousplain plainweave weavestructures structures Figure3. 3. Skewness Skewness (%)

Figure 3 shows that the dobby fabric (Sample 1) has the lowest percentage of skewness out of all the plain Figure 3 shows that the dobby fabric (Sample 1) has the lowest percentage of skewness out of all the structures. This happened due to the fact that the interlacement of the dobby design is more congested plain structures. This happened due to the fact to that theininterlacement of of theskewness dobby design is more than it is in the other designs. This property tends result the lower value [13]. The canvas fabric (Sample 3) has average to the other derivatives. congested than it is an in the otherskewness designs. compared This property tends to result in the lower value of skewness

[13]. The canvas fabric (Sample 3) has an average skewness compared to the other derivatives. Shrinkage: the shrinkage percentage of the plain weave samples 1-5 was analysed and the results www.textile-leather.com 231 are shown below.

plain structures. This happened due to the fact that the interlacement of the dobby design is more congested than it is in the other designs. This property tends to result in the lower value of skewness NURUNNABI M, et al. Study on Comparative Analysis of Basic Woven Fabrics â&#x20AC;Ś TLR 3 (4) 2020 226-239.

[13]. The canvas fabric (Sample 3) has an average skewness compared to the other derivatives.

Shrinkage: the shrinkage percentage of the plain weave samples 1-5 was analysed and the results Shrinkage: the shrinkage percentage of the plain weave samples 1-5 was analysed and the results are shown are shown below. below. Fabric structure vs shrinkage of plain structures

-0,50%

Sample 1

Shrinkage, %

-1% -2%

Sample 2

-1,70%

-3%

-1,80%

Sample 3

-0,40%

Sample 4

Sample 5 -1,80%

-2,00%

-4%

-3,70% -4,00%

-5%

-3,90%

-6%

-6,60%

-7%

Warp

-8%

Weft

Fabric structure

Figure 4. Shrinkage (%) of various plain weave structures Figure 4. Shrinkage (%) of various plain weave structures

NURUNNBI M, et al. Study on Comparative Analysis of Basic Woven Fabrics â&#x20AC;Ś TLR 0 (0) 2020 00-00.

Figure 4 shows that the canvas and the oxford canvas fabric (Samples 3 and 4) have the lowest shrinkage Figure 4 shows the canvas oxford canvas 3 and 4) have the lowest percentage in weftthat direction. This isand due the to the fact that the fabric weave(Samples pattern with a higher number of interlacements lower shrinkage value [14].of shrinkagehas percentage in weft direction. This due to the fact that the pattern with a higher Elongation: the elongation percentage theis plain weave samples 1-5weave was analysed Elongation: elongation percentage of the plain weave number ofthe interlacements has lower shrinkage value [14].samples 1-5 was analysed and the results are and the results are shown below. shown below. Fabric structure vs elongation of plain structures 35%

29,20%

Elongation, %

30% 25% 20% 15%

22,40%

21,80% 12,10%

14,40%

12,20%

10% 5% 0%

Warp

Sample 1

Sample 2

Weft

Sample 3

Fabric Structure

Figure 5. Elongation Elongation(%) (%)of ofvarious variousplain plainweave weavestructures structures Figure 5.

Figure 5 shows that the dobby fabric (Sample 2) has the highest percentage of elongation. The reason Figure 5 shows that the dobby fabric (Sample 2) has the highest percentage of elongation. The behind this is the high weft density [15]. Looking at Table 1 we can see that Sample 2 has the highest PPI reason thisother is thefabrics. high weft density [15]. Looking at Table 1 we can see that Sample 2 has the value outbehind of all the From thePPI above analysis a conclusion that Sample 3 (canvas fabric) has the best elongation highest value out ofwe all can the come other to fabrics. percentage compared to the From the above analysis weother can plain comestructures. to a conclusion that Sample 3 (canvas fabric) has the best

elongation percentage compared to the other plain structures. Twill-weave structure: Samples 6-9, which represent the twill-weave structure, were taken and 232 www.textile-leather.com tested in order to compare their mechanical properties. The results are shown below.

Tear strength: the tear strength of the twill-weave samples 6-9 was analysed and the results are

NURUNNABI M, et al. Study on Comparative Analysis of Basic Woven Fabrics … TLR 3 (4) 2020 226-239. NURUNNABI M, et al. Study on Comparative Analysis of Basic Woven Fabrics … TLR 0 (0) 2020 00-00.

Twill-weave structure: Samples 6-9, which represent the twill-weave structure, were taken and tested in NURUNNABI M, ettheir al. Study on Comparative Analysis Basic Woven Fabrics … TLR 0 (0) 2020 00-00. order to compare mechanical properties. Theofresults are shown below. Fabric structure vs tear strength Tear strength: the tear strength of the twill-weave samples 6-9 was analysed and the results are shown below. of twill structures

Tear Strength, Tear N Strength, N

30 25 20 30 15 25 10 20 5 15 0 10

20 13 20 13

Sample 6

14,6

7,83

14,6

7,83

Sample 7

5 0

23,7

Fabric structure vs tear strength 21 of twill structures

18,1 23,7 18,1 Warp

Sample 8

Fabric Structure

Weft

Sample 9 Warp

Figure of various twill Sample 6 6. Tear strength Sampleanalysis 7 Sample 8 fabrics

Weft

Sample 9

Fabric Structure

Figure 6 shows that SampleFigure 9, herringbone fabric, hasof greatest amount of tear strength, both in 6.6.Tear analysis various twillfabrics fabrics Figure Tearstrength strength analysis ofthe various twill warp and weft direction. The other twill-weave structures show much lesser tear strength. This is Figure 6 shows that Sample 9, herringbone fabric, has the greatest amount of tear strength, both in warp because of the warp and weft density of the fabric. test results areofparallel to the findings Figure 6 shows that Sample 9, yarn herringbone fabric, has theThis greatest amount tear strength, both in and weft direction. The other twill-weave structures show much lesser tear strength. This is because of Krook and Foxdirection. [11].density TheyThe discovered thatThis thetest tear strength ofparallel themuch fabric increases density warp and weft twill-weave structures show tear as strength. This is theof warp and weft yarn ofother the fabric. results are to lesser the findings ofthe Krook and of Fox theThey longitudinal yarn isthe decreased. Looking Table 1 we cantest that the herringbone fabric has is [11]. discovered that tearyarn strength of the fabric increases assee the density the longitudinal yarn because of the warp and weft density ofatthe fabric. This results areof parallel to the findings decreased. Lookingand at Table 1 we can see derivatives; that the herringbone fabric has much lower tear EPI and PPI than the much lower PPIThey than the other is why it the has much greater [16]. of Krook andEPI Fox [11]. discovered that the tearthat strength of fabric increases as strength the density of other derivatives; that is why it has much greater tear strength [16]. Tensile strength: yarn the tensile strengthLooking of the twill-weave 6-9 was and the results are the longitudinal is decreased. at Table 1 samples we can see that analysed the herringbone fabric has Tensile strength: the tensile strength of the twill-weave samples 6-9 was analysed and the results are shown shown below. much lower EPI and PPI than the other derivatives; that is why it has much greater tear strength [16]. below. Tensile strength: the tensile strength of the twill-weave samples 6-9 was analysed and the results are shown below.

Fabric structure vs tensile strength of twill structures

Tensile Strength, Tensile N Strength, N

800

Warp

600 800 400 600 200 400 0 200 0

401

Warp

258 401

Sample 6 258

Weft Fabric structure vs tensile strength of twill structures Weft

513

648

476 330 648

513 176

Sample 7 Fabric Structure 176

161 476

Sample 8

330 Sample 9

161

Sample 67.7.Tensile Sampleanalysis 7 Sample 8 fabrics Figure of various twill fabrics Figure Tensilestrength strength analysis twill

Sample 9

Fabric Structure

Figure 7 shows that the herringbone fabric (Sample 9) has much greater tensile strength than the other derivFigure 7 shows that the herringbone fabric (Sample 9) has much Figure 7. Tensile strength analysis various twillgreater fabrics tensile strength than the atives of the twill structure. This is due to the fact that theofherringbone fabric has much higher warp way other derivatives of the twill structure. This is due to the fact that the herringbone has much and weft way strength, which directly contributes to greater tensile strength than in the fabric other fabrics [12].

Figure 7 shows that the herringbone fabric (Sample 9) has much greater tensile strength than the other derivatives of the twill structure. This is due to the fact that the herringbone fabric has much www.textile-leather.com 233

strength than in the other fabrics [12]. Skewness: skewness percentage of the twill-weave samples was analysed and the results are NURUNNABI M,the et al. Study on Comparative Analysis of Basic Woven Fabrics6-9 â&#x20AC;Ś TLR (4) 2020tensile 226-239. higher warp way and weft way strength, which directly contributes to 3greater shown below. strength than in the other fabrics [12]. Skewness: thethe skewness percentage of the twill-weave 6-9 6-9 waswas analysed and the are shown Skewness: skewness percentage of the twill-weave analysed andresults the results are Fabric structuresamples vs samples skewness of twill structures below. shown below. 1,2%

1,00%

Skewness, % Skewness, %

1,0% 0,8% 1,2% 0,6% 1,0% 0,4% 0,8% 0,2% 0,6% 0,0% 0,4%

0,80%

1,00% 0,80%

1,00%

1,00% 0,30%

Fabric Skewness

Sample 6

Fabric Skewness

0,2% 0,0%

Fabric structure vs skewness of twill structures

Sample 7

0,30%

Sample 8

Sample 9

Fabric Structure Figure (%) analysis of various twill8 fabrics Sample 6 8. Skewness Sample 7 Sample

Sample 9

Fabric Structure

Figure 8 shows that the herringbone fabric (%) (Sample the twill lowest percentage of skewness. This is Figure 8. Skewness analysis9)ofhas various fabrics Figure 8. Skewness (%) analysis of various twill fabrics

because the herringbone or any other type of the zigzag twill (in which the diagonal lines do not Figure 8 shows that the herringbone (Sample hasfabric) the lowest percentage of skewness. Thisbecoming is because follow same acrossfabric the width of9)the eliminate the risk of of theskewness. fabric Figure 8 the shows thatdirection the herringbone fabric (Sample 9) has the lowest percentage This is the herringbone or any other type of the zigzag twill (in which the diagonal lines do not follow the same skewed. This is because, in such weaves, floats (in-plane levers) act in opposition to each other [13]. becauseacross the herringbone other type of the therisk zigzag twill (in which the skewed. diagonalThis linesis do not direction the width ofor theany fabric) eliminate of the fabric becoming because, Shrinkage: the shrinkage percentage of the twill-weave samples 6-9 was analysed and the results are infollow such weaves, floats (in-plane levers) in opposition to each other [13]. the same direction across theact width of the fabric) eliminate the risk of the fabric becoming Shrinkage: the shrinkage percentage of the twill-weave samples 6-9act wasinanalysed andtothe results are shown shown below. skewed. This is because, in such weaves, floats (in-plane levers) opposition each other [13]. below. Shrinkage: the shrinkage percentage of the twill-weave samples 6-9 was analysed and the results are

shown below.

Fabric structure vs shrinkage of twill structures 0%

-1% Shrinkage, % Shrinkage, %

-2% 0% -3% -1% -4% -2% -5% -3% -6% -4% -7% -5% -8% -6% -9% -7% -8% -9%

Sample 6

Sample -3,50% 6

Sample 7 Sample 8 Fabric structure vs shrinkage of-1,10% twill structures -1,70% Sample 7 -1,10%

-3,50%

Sample 9

-2,60%9 Sample

Sample 8 -1,70%

Warp -2,60%

-5,40%

-7,50%

Warp

-5,40%

Weft

Weft -8,00%

Fabric Structure

-7,50% Figure -7,50%twill Figure Shrinkage(%) (%)analysis analysisofofvarious various twillfabrics fabrics 9. 9. Shrinkage

Fabric Structure

-8,00%

Figure 9 shows that 2/2 S twill and 2/1 S twill fabrics (Samples 7 and 8) have the lowest shrinkage percentage. Figure 9.pattern Shrinkagewith (%) analysis of various twill This is due to the fact that the weave a higher number offabrics interlacements has lower shrinkage value [14]. Elongation: the elongation percentage of the twill-weave samples 6-9 was analysed and the results are shown below. 234 www.textile-leather.com

Elongation: the elongation percentage of the twill-weave samples 6-9 was analysed and the results NURUNNABI M, et al. Study on Comparative Analysis of Basic Woven Fabrics â&#x20AC;Ś TLR 3 (4) 2020 226-239. are shown below.

Fabric structure vs elongation of twill structures 35%

29,40%

Elongation %

30%

26,24%

23,80%

25%

24,20%

27,30%

20% 15%

16,40%

10%

15,30%

11,59%

Warp

Sample 6

Sample 7

Sample 8

Weft

Sample 9

Fabric Structure

Figure 10. Elongation (%) analysis of various twill fabrics Figure 10. Elongation (%) analysis of various twill fabrics

Figure 10 shows that 2/2 S twill fabric (Sample 7) has the highest percentage of elongation. The reason Figure 10 shows that 2/2 S twill fabric (Sample 7) has the highest percentage of elongation. The behind this is the high weft density [15]. Looking at Table 1, we can see that Sample 7 has the highest PPI reason this is the high weft density [15]. Looking at Table 1, we can see that Sample 7 has the value outbehind of all the other fabrics. From the above analysis weallcan tofabrics. a conclusion that Sample 9 (herringbone fabric) shows the optimum highest PPI value out of thecome other property compared to the other twill structures. From the above analysis we can come to a conclusion that Sample 9 (herringbone fabric) shows the

optimum property comparedanalysis to the other twill structures. Plain, twill and satin combined On the basis of the above analysis, Sample 3 of the plain structure, Sample 9 of the twill structure and Sample 10Plain, of thetwill satin structure are takenanalysis for the combined analysis of the mechanical properties of those fabrics. and satin combined Tear strength: the tear the derivativesAnalysis of the of plain (Sample 3), twillâ&#x20AC;Ś(Sample and00-00. satin (Sample NURUNNBI M, strength et al. Studyofon Comparative Basic Woven Fabrics TLR 0 (0) 9) 2020 On the basis of the above analysis, Sample 3 of the plain structure, Sample 9 of the twill structure 10) fabric was analysed and the results are shown below. and Sample 10 of the satin structure are taken for the combined analysis of the mechanical properties of those fabrics.

Fabric structure vs tear strength

of plain, twill and of satin structures Tear strength: the tear strength of the derivatives the plain (Sample 3), twill (Sample 9) and satin 60

Tear Strength, N

(Sample 10) fabric was analysed and the results are shown below. 50 43

37,8

40 30

36,9

23,7

20 10 0

13,1

Sample 3 (Canvas)

Sample 9 (Herringbone)

Warp

Weft

Sample 10 (Satin)

Fabric Structure

Figure 11.Figure Tear strength analysisanalysis of plain, 11. Tear strength oftwill plain,and twillsatin and fabrics satin fabrics

Looking at Figure 11, we can see that Sample 3, which is a plain fabric, has the greatest tear strength. Tear Looking at Figure 11, we can see that Sample 3, which is a plain fabric, has the greatest tear strength. strength of the plain weave is greater than that of the twill weave because the plain weave is less porous Tear strength of the plain weave is greater than that of the twill weave because the plain weave is less porous and has a higher number of warp and weft interlacements. The plain weave has the www.textile-leather.com 235 greatest strength in warp way due to the increased number of crossover points compared to other weave types [7].

Tear strength of the plain weave is greater than that of the twill weave because the plain weave is less porous has aonhigher number of warp andWoven weft interlacements. plain weave has the NURUNNABI M, etand al. Study Comparative Analysis of Basic Fabrics â&#x20AC;Ś TLR 3 (4)The 2020 226-239. greatest strength in warp way due to the increased number of crossover points compared to other types [7]. and weave has a higher number of warp and weft interlacements. The plain weave has the greatest strength in warpTensile way due to the increased number of of the crossover pointsofcompared other weave [7]. 9) and strength: the tear strength derivatives the plain to (Sample 3), twilltypes (Sample Tensile strength: tear strength of the derivatives the plainbelow. (Sample 3), twill (Sample 9) and satin satin (Sample the 10) fabric was analysed and the resultsofare shown (Sample 10) fabric was analysed and the results are shown below. Fabric structure vs tensile strength of plain, twill and satin structures

Tensile strength, N

800 600

600

660

648

400 382

320,2

330

200 Warp 0

Sample 3 (Canvas)

Sample 9 (Herringbone)

Weft

Sample 10 (Satin)

Structure NURUNNABI M, et al. Study on Comparative AnalysisFabric of Basic Woven Fabrics â&#x20AC;Ś TLR 0 (0) 2020 00-00.

Figure 12.12. Tensile strength twilland andsatin satinfabrics fabrics Figure Tensile strengthanalysis analysis of of plain, plain, twill

number compared to other weave structures. Because of the increased number of interlacements, Looking at Figure 12, we can see that Sample 3, which is a plain fabric, has the greatest tensile strength. This at Figure in 12, weyarns can see Samplewhich 3, which is a plaintofabric, has thetensile greatest tensileof theLooking frictional alsothat increases, theingreater strength is due to the factpoint that thethe interlacement points of the plaincontributes fabric are greater number compared to other strength. This is due to the fact that the interlacement points of the plain fabric are greater in weave structures. the fabric [17]. Because of the increased number of interlacements, the frictional point in the yarns also increases, which to the greater tensile strengthof ofthe the plain fabric(Sample [17]. 3), twill (Sample 9) and Skewness: thecontributes skewness percentage of the derivatives Skewness: the skewness percentage of the derivatives of the plain (Sample 3), twill (Sample 9) and satin satin (Sample 10) fabric was analysed and the results are shown below. (Sample 10) fabric was analysed and the results are shown below. Fabric structure vs skewness of plain, twill and satin structures

Skewness, %

2,5% 2,0%

1,80%

1,60%

1,5% 1,0% 0,30%

0,5% 0,0%

Skewness

Sample 3 (Canvas)

Sample 9 (Herringbone)

Sample 10 (Satin)

Fabric Structure Figure13. 13.Skewness Skewnesspercentage percentage analysis of plain, Figure plain, twill twilland andsatin satinfabrics fabrics

Figure 13 shows that Sample 9 (herringbone fabric) has the lowest skewness percentage compared to the Figure 13 shows that Sample 9 (herringbone fabric) has the lowest skewness percentage compared plain and satin structure. Generally, the plain weave tends to show lower skewness percentage than the to the plain and satin structure. Generally, the plain weave tends to show lower skewness twill weave. But the herringbone or any other type of the zigzag twill structure (in which the diagonal lines thansame the twill weave. But the herringbone any eliminate other typethe of risk the of zigzag twill structure dopercentage not follow the direction across width of the or fabric) the fabric becoming skewed. Thisthe is because, such floats levers) across act in opposition to the eachfabric) othereliminate [13]. (in which diagonal in lines doweaves, not follow the(in-plane same direction the width of

the risk of the fabric becoming skewed. This is because, in such weaves, floats (in-plane levers) act in 236 www.textile-leather.com opposition to each other [13]. Shrinkage: the shrinkage percentage of the derivatives of the plain (Sample 3), twill (Sample 9) and

NURUNNABI M, et al. Study on Comparative Analysis of Basic Woven Fabrics â&#x20AC;Ś TLR 3 (4) 2020 226-239. NURUNNBI M, et al. Study on Comparative Analysis of Basic Woven Fabrics â&#x20AC;Ś TLR 0 (0) 2020 00-00. M, et al. Study on Comparative Analysis of Fabrics â&#x20AC;Ś3), TLRtwill 0 (0)(Sample 2020 00-00. Shrinkage:NURUNNBI the shrinkage percentage of the derivatives ofBasic the Woven plain (Sample 9) and satin (Sample 10) fabric was analysed andFabric the structure results are shown below. vs shrinkage of plain, twill and satin structures

-0,50%

0% -2%

-3%

-1%

-4%

-2%

-5%

-3%

-6%

-4%

-7%

-5%

-8%

-6%

-9%

-7%

-10%

-8%

Shrinkage, %

Fabric structure vs shrinkage of Sample plain, twill and satin structures 9 (Herringbone)

Sample 3 (Canvas)

-1%

Sample 10 (Satin)

-0,50% -2,00% Sample 3 (Canvas)

Sample 9 (Herringbone)

-2,60%

-2,00%

Sample 10 (Satin)

-6,00%

-2,60%

-6,00% -8,00% Warp

-9,30%

Weft -8,00%

-9% -10%

-9,30%

Fabric Structure

Warp

Weft

Figure 14. Shrinkage percentage analysis of plain, twill and satin fabrics Fabric Structure

Figure 14.Figure Shrinkage percentage analysis of plain, twill and satin fabrics 14. Shrinkage percentage analysis of plain, twill and satin fabrics

Looking at Figure 14, we can see that Sample 3, which is a plain weave, has the lowest shrinkage

Looking at Figurecompared 14, we cantosee that Sample which is a plain has thethe lowest shrinkage percentage percentage the twill and 3, satin weave. Thisweave, is because increased number of Looking at Figure 14, we can see that Sample 3, which is a plain weave, has the lowest shrinkage compared to the twill andlower satinshrinkage weave. This is because increased of have interlacements causes interlacements causes values [14]. Thethe twill and satinnumber structures comparatively percentage compared to the twill and satin weave. This is because the increased number lower shrinkage values [14]. The twill and satin structures have comparatively lower number of interlace- of lower number of interlacement points, which is why they have higher shrinkage values. ment points, which is why they have shrinkage interlacements causes lowerhigher shrinkage valuesvalues. [14]. The twill and satin structures have comparatively Elongation: the elongation percentage of the derivatives the plain (Sample twill (Sample 9) and Elongation: the number elongation percentage ofpoints, the derivatives of of the plain (Sample 3),3), twill (Sample lower of interlacement which is why they have higher shrinkage values.9) and satin satin 10) (Sample fabric was analysed the are results are below. shown below. (Sample fabric10) was analysed and the and results shown Elongation: the elongation percentage of the derivatives of the plain (Sample 3), twill (Sample 9) and satin (Sample 10) fabric was analysed and the results are shown below. Fabric structure vs elongation of plain, twill and satin structures 40%

Fabric structure vs elongation of plain, twill and satin structures

30%

40%

25%

35%

20%

30%

15%

25%

10%

20%

15%

10%

Elongation, %

35% 22,40%

36,67% 24,20%

22,40%

14,25%

15,30% 12,20%

Warp

14,25% Weft

15,30% 12,20%

5% Sample 3 (Canvas) 0%

36,67%

24,20%

Sample 3 (Canvas)

Sample 9 (Herringbone) Fabric Structure Sample 9 (Herringbone)

Warp

Sample 10 (Satin)

Weft

Sample 10 (Satin)

Figure 15. Elongation percentage analysis of plain, twill and satin fabrics Figure 15. Elongation percentage analysis of Structure plain, twill and satin fabrics Fabric

Figure 15 shows that Sample 3,Figure which is a plain percentage weave, has the of lowest elongation percentage and Sample 15. Elongation analysis plain, twill and satin fabrics Figure 15 shows that Sample 3, which is a plain weave, has the lowest elongation percentage and 10, which is a satin fabric, has relatively higher shrinkage percentage than the other two structures. This is 10, that which is afabrics satin fabric, has relatively higher shrinkage percentage thanand theweft other two dueSample to the fact plain have higher number of interlacements between warp yarn in the Figure 15 shows that Sample 3, which is a plain weave, has the lowest elongation percentage and fabric structure compared to the twill and satin structure. This high number of intersecting points contribSample 10, which is a satin fabric, has relatively higher shrinkage percentage than the other two utes to the lower elongation percentage of the plain fabric [15]. www.textile-leather.com 237

NURUNNABI M, et al. Study on Comparative Analysis of Basic Woven Fabrics … TLR 3 (4) 2020 226-239.

From the above discussion and the analysis, we can come to a conclusion that the canvas structure produced in the air-jet loom shows significantly better mechanical properties than the twill and satin fabrics produced in the same loom.

CONCLUSION The woven fabric has a much broader scope of end utilization than other kinds of fabric. That is why the manufacturing process should be adjusted to fulfil those performance prerequisites. The physical structures and the chemical properties of the woven fabric will determine how it will perform and whether it will be acceptable for a particular use or not. Fabric testing plays a crucial role in guaranteeing product quality, regulating compliances, and the assessment of the performance of a textile material. Creating a clear concept of the various mechanical properties of the woven fabric can lead the path of further improvement of the woven fabric structure, which will be beneficial for many end-use applications, especially for technical textiles and protective clothing. In this research, the effectiveness of mechanical properties of varying weave structures was shown. It should be noted that, even if the fabric parameters remain the same, a more complex mechanical behaviour of fabrics can be implanted and studied as well. More advanced research work on this topic can be done in order to increase the knowledge even further.

REFERENCES [1] Patil RB, Turukmane R. Structural behavior of fabric design on mechanical properties of woven fabrics. Melliand International. 2019. 25;83-85. [2] Patil YB, Kolte PP, Daberao AM, Sharma B. A critical analysis of airjet loom performance. Man Made Textiles in India. 2018. 46(10):350-353. [3] Shintani R, Okajima A. Air flow through a weft passage of profile reed in air jet looms. Journal of Textile Engineering. 2002; 48(2):56-63. https://doi.org/10.4188/jte.48.56 [4] Uno M. A Study on an Air-Jet Loom with Substreams Added: Part 1: Deriving the Equation of Motion for Weft. Journal of the Textile Machinery Society of Japan. 1972; 18(2):37-44. https://doi.org/10.4188/ jte1955.18.37 [5] Ishida M, Okajima A. Flow characteristics of the main nozzle in an air-jet loom: part I: measuring flow in the main nozzle. Textile Research Journal. 1994; 64(1):10-20. https://doi.org/10.1177/004051759406400102 [6] Kim SJ. Effects of the Air-Jet Loom Characteristics on the Hand Properties of the Sensitive Mixture Fabrics. Textile Coloration and Finishing. 2008; 20(6):63-68. https://doi.org/10.5764/TCF.2008.20.6.063 [7] Jahan I. Effect of fabric structure on the mechanical properties of woven fabrics. Advance Research in Textile Engineering. 2017; 2(2). [8] Booth JE. Principles of textile testing. London: Heywood Books; 1970. [9] Dolatabadi KM, Kovar R. Anisotropy in tensile properties of plain weave fabric–Part I: The meso-scale model. Textile Research Journal. 2012; 82(16):1666-1676. https://doi.org/10.1177/0040517511435003 [10] Triki E, Dolez P, Vu-Khanh T. Tear resistance of woven textiles–criterion and mechanisms. Composites Part B: Engineering. 2011; 42(7):1851-1859. https://doi.org/10.1016/j.compositesb.2011.06.015 [11] Krook CM, Fox KR. Study of the tongue-tear test. Textile Research Journal. 1945; 15(11):389-396. https:// doi.org/10.1177/004051754501501102 [12] Majumdar A, et al. Empirical modelling of tensile strength of woven fabrics. Fibers and Polymers. 2008; 9:240-245. https://doi.org/10.1007/s12221-008-0038-9

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[13] Alamdar-Yazdi A. Weave structure and the skewness of woven fabric. Research Journal of Textile and Apparel. 2004; 8(2):28-33. https://doi.org/10.1108/RJTA-08-02-2004-B004 [14] Topalbekiroglu M, Kubra KH. The effect of weave type on dimensional stability of woven fabrics. International Journal of Clothing Science and Technology. 2008; 20(5):281-288. https://doi. org/10.1108/09556220810898890 [15] Abou Nassif GA. Effect of weave structure and weft density on the physical and mechanical properties of micro polyester woven fabrics. Life Science Journal. 2012; 9(3):2-7. [16] Eryuruk SH, Kalaoglu F. The Effect Of Weave Construction On Tear Strength Of Woven Fabrics. Autex Research Journal. 2015; 15(3):207-214. https://doi.org/10.1515/aut-2015-0004 [17] Amin RM, Haque MM. Effect of weave structure on fabric properties. Annals of the University of Oradea, Fascicle of Textiles, Leatherwork. 2011; 12:161-165.

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Book – Hu J. Structure and mechanics of woven fabrics. Cambridge: Woodhead Publishing Ltd; 2004. 61 p. • Author AA. Title of book. # edition [if not first]. Place of Publication: Publisher; Year of publication. Pagination. Edited book - Sun G, editor. Antimicrobial Textiles. Duxford: Woodhead Publishing is an imprint of Elsevier; 2016. 99 p. • Editor AA, Editor BB, editors. Title of book. # edition[if not first]. Place of Publication: Publisher; Year. Pagination. Chapter in a book - Luximon A. Handbook of Footwear Design and Manufacture. Cambridge: Woodhead Publishing Limited; 2013. Chapter 5, Foot problems and their implications for footwear design; p. [90-114]. • Author AA, Author BB. Title of book. # edition[if not first]. Place of Publication: Publisher; Year of publication. Chapter number, Chapter title; p. [page numbers of chapter]. Electronic book – Strasser J. Bangladesh’s Leather Industry: Local Production Networks in the Global Economy [Internet]. s.l.: Springer International Publishing; 2015 [cited 2017 Feb 07]. 96 p. Available from: https://link. springer.com/book/10.1007%2F978-3-319-22548-7 • Author AA. Title of web page [Internet]. Place of Publication: Sponsor of Website/Publisher; Year published [cited YYYY Mon DD]. Number of pages. Available from: URL DOI: (if available) Conference paper – Ferreira NG, Nobrega LCO, Held MSB. The need of Fashion Accessories. In: Mijovic B. editor. Innovative textile for high future demands. Proceedings 12th World Textile Conference AUTEX; 13-15 June 2012; Zadar, Croatia. Zagreb: Faculty of Textile Technology, University of Zagreb; 2012. p. 1253-1257. • Author AA. Title of paper. In: Editor AA, editor. Title of book. Proceedings of the Title of the Conference; Date of conference; Place of Conference. Place of publication: Publisher’s name; Year of Publication. p. page numbers. Thesis/dissertation – Sujeevini J. Studies on the hydro-thermal and viscoelastic properties of leather [dissertation]. Leicester: University of Leicester; 2004. 144 p. • Author AA. Title of thesis [dissertation]. Place of publication: Publisher; Year. Number of pages Electronic thesis/dissertation – Covington AD. Studies in leather science [dissertation on the internet]. Northampton: University of Northampton; 2010. [cited 2017 Jan 09]. Available from: http://ethos.bl.uk/ OrderDetails.do?uin=uk.bl.ethos.579666 • Author AA. Title of thesis [dissertation on the Internet]. Place of publication: Publisher; Year. [cited YYYY abb. month DD]. Available from: URL This quick reference guide is based on Citing Medicine: The NLM Style Guide for Authors, Editors, and Publishers (2nd edition). Please consult this source directly for additional information or examples.

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