Bark cloth based beaker by Mehrwerk Designlabor Bark cloth materials // Bio-based materials → p. 058
Pulp Collection by Jo Meesters Recycling paper // Recycling materials → p. 089
Hood with in-sew n shape memory alloys designed by Max Schäth Shape memory alloys (SMAs) // Shape-changing materials
→ pp. 125/126
Lamp with ceramic foam lampshade by Nextspace, serien.lighting Ceramic foam // Lightweight construction and insulation materials → p. 103
OLED light branch by Hannes Wettstein Organic light-emitting diodes (OLEDs) // Energy-generating and light-influencing materials → p. 173
“E-Static Shadows” light installation by Zane Berzina Light-emitting diodes (LEDs) // Energy-generating and light-influencing materials → p. 172
“E-Static Shadows” light installation by Zane Berzina Light-emitting diodes (LEDs) // Energy-generating and light-influencing materials → p. 172
Uses of Luminex Ž Light-emitting and luminescent materials // Energy-generating and light-influencing materials → p. 171
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Polylactic acid or polylactide (PLA) is one of the most important bio crude plastics in the current sustainability debate, as its properties are comparable with those of PET. Generally speaking, bio crude plastics cannot be used directly, but through compounding are mixed with aggregates and additives to suit their specific purpose. Although the material was discovered as early as the 1930s, it has only recently been produced on a large scale, by NatureWorks ®.
Sustainability aspects based on renewable resources // can be recycled // can be composted in industrial plants
BIO-based Materials
Bioplastics Based on Polylactic Acid
Material concept and properties
PLA is produced either by fermenting viscous sugar syrup or by the bacterial fermentation of starch or any kind of sugar. The raw material is colorless, shiny, and reminiscent of polystyrene. It is completely biodegradable. The low migration behavior for oxygen or steam makes PLA an interesting alternative for food packaging. A disadvantage is that some polylactides soften at very low temperatures compared with alternative plastics. The mechanical resistance in particular can be improved by adding fibers. PLA surfaces are water-repellent. Depending on its composition the material is either quickly biodegradable or remains stable for several years. Even though PLA is sourced from renewable resources the CO2 footprint for its production is relatively high. It requires a similar level of energy as the manufacture of polypropylene. Compared with the typical mass plastics the production of PLA is still much more cost-intensive; the price is higher than for PET.
Properties similar property profile to PET // low permeability for gases // water-repellent surface // transparent // relatively low heat-stability of just over 60°C
Cell phone holder made of PLA bioplastics (Source: NatureWorks ®)
PLA food packaging (Source: NatureWorks ®)
PLA foil packaging (Source: NatureWorks ®)
Making foil using blow extrusion (Source: FKuR)
Use and processing
PLA blends can be shaped and formed using customary techniques such as injection molding, thermoforming or blow molding (temperatures: 170–210°C). Foils are extruded. Welding or
160 140 120 100 80 60 40 VST B50 [°C] Vicat temperature of various polymers in comparison with conventional plastics
PA6
PL
PET
ABS
PP
PE-HD
Cellulose derivatives
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Starch blends
PLA
PHAs
PLA blends
200
Biopolyester
Heat-stability of biopolymers PCL
In recent times bioplastics have carved out a niche in particular in the packaging industry e.g., for foils and yogurt cartons. Given that their properties are similar to PET, polylactic acids are expected to increase their stake in the packaging market in the medium term. Moreover, companies in the automobile and entertainment industries are also showing a great interest in using PLA. The fact that it is biodegradable makes the material interesting for use in geo-textiles in the agricultural sector and landscape work. Its use in technical products also seems feasible in the guise of fiber reinforcement. Biocompatible quali ties also makes PLA suitable for various medical technology applications – for instance, it can be injected in cosmetic surgery to fill out wrinkles. Its low density is a decisive criterion for its use in lightweight constructions.
sticking is used to produce joints. PLA semifinished products can be processed using the techniques normally applied for processing wood and metal.
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Products
BIO-based Materials
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NatureWorks -Polymer Since 2002 NatureWorks has been the world’s largest producer of the bio crude plastic polylactic acid (PLA). The company has developed a method for transforming the sugar occurring naturally in plants into a patented polylactide polymer, which is sold under the brands NatureWorks -Polymer and Ingeo -fiber.
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Ecovio Ecovio is the first plastic blend by BASF, which is produced on the basis of renewable resources and is biodegradable. The main constituent with a proportion of 45 % is polylactic acid (PLA). On account of its special properties it is especially suitable for packaging. The material can be printed in eight colors and has a high mechanical resistance. Special modifications can be processed using injection molding and extrusion.
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Bioflex Bioflex is a PLA-based co-polyester blend, which, depending on the required property profile, consists almost entirely of renewable resources. It is especially suited for the manufacture of thinwalled foils with high tear resistance, and has similar properties to the classic packaging plastics PE, PP and PS. Bioflex can be dyed and printed, is approved for contact with foods and its elasticity can be adjusted as required.
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The second heavyweight amongst the bio crude plastics is polyhydroxybutric acid (PHB), as its property profile is similar to that of the widely employed polypropylene (PP). Discovered in France just under 90 years ago, the polyester is produced in almost every living organism, from sugar to starch and oils. It is the most important representative of the polyhydroxyalcanoates (PHA). At present, high production costs hinder the mass deployment of bioplastics. That said, various efforts are being made to lower these costs. In particular companies from the South American sugar industry are getting involved in the industrial production of PHB. According to estimates microbes can transform three kilos of sugar into one kilo of bioplastics.
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Ecogehr PLA In summer 2008 the GEHR plastics plant became the first manufacturer worldwide of technical semi-finished biopolymer-based products. All the materials based on polylactides are grouped together under the Ecogehr PLA brand. Depending on the requirements the program includes blends of polylactides with lignin or wooden fibers with various qualities. The materials are physiologically harmless and can be composted or burned.
Semi-finished products made of Ecogehr ®PLA (Source: GEHR Kunststoffwerk)
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Ingeo Salewa was one of the first sports clothing makers to bring to market outdoor clothing made of PLAfibers by NatureWorks , which are biodegradable. Another advantage over conventional polyester fibers is that they do not simply absorb sweat but transport it away from the body.
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Helmet made using PLA fiber material (Source: NatureWorks ®)
Properties similar property profile to PP // low oxygen diffusion // UV stability // biocompatible qualities // high fracture susceptibility // PHB melts at temperatures above 130°C Sustainability aspects based on renewable resources // biodegradable without harmful residues
Bioplastics based on polyhydroxybutric acid
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Natural caoutchouc is used in almost 40% of all industrial rubber production today. As a resilient fungus currently affects rubber trees, scientists are working on an alternative source. It has been discovered that the milk of dandelions has similar properties to latex, though the fact that it polymerizes as soon as it is extracted is problematic. Scientists have now localized an enzyme that triggers this effect. Modifying the plant through gene technology promises to make the latex milk usable for industrial applications and to considerably increase the amount of naturally produced milk.
BIO-based Materials
Use
Natural elastomers are used in balloons, condoms, gloves and textiles as well as in technical products such as tires, rubber springs, membranes, engine mountings and seals. Natural rubber is found in flooring and is processed into seals, hoses and cable coating. When wet, natural rubber is sticky and suitable as an adhesive substance.
Natural latex baby’s comforter
Properties thermoplastic // even property distribution // high degree of rigidity and bending strength // good moisture resistance // very stable // acoustic qualities Sustainability aspects based on re newable raw materials // substitute for tropical woods in outdoor use // crude oil-free matrix materials are biodegradable
Wood polymer composites (WPC)
Sourcing natural caoutchouc in Thailand
Internationally the term “wood plastic composites” (WPC) has established itself as a description of wood-polymer composites. In German-speaking countries, wood polymer composites are often referred to as “liquid wood”, as WPCs can be processed in a thermoplastic process, that is, melted and shaped three-dimensionally.
Material concept and properties
WPCs consist of wood fibers, a plastic matrix (PP, PE or PLA) and various additives. The proportion of wood fiber is generally between 50–90%. As the latter has no fiber direction in the subsequently shaped product, liquid wood has an even property distribution. The positive qualities of WPC are its low shrinkage and high degree of rigidity, the low thermal expansion and high resistance to moisture. These properties are particularly desirable in the manufacture of precision components, which are not or at least not easily made of wood. Use and processing
WPC shelving system (Source: Mehrwerk Designlabor)
The use of WPCs is of interest whenever complex geometrical shapes with a wooden appearance are needed. Typical products are casings for electronic devices, handles, furniture, outdoor ground surfaces, bio-urns, fashion accessories and building components for vehicle interiors. In building interiors they are used for skirting boards and shelving systems. Wood polymer materials can be processed using typical plastic processing techniques such as injection molding, extrusion,
compression molding and thermoforming. Due to the wood content the maximum processing temperature should not exceed 200°C.
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Products
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Fasal Fasal was developed at the Institute for Natural Materials Technology in Tulln with a view to manufacturing products with a wood-like appearance that are based on renewable raw materials such as wood and corn, and has been optimized for the injection molding process. Products made from Fasal have very hard surfaces, a wood-like appearance, high bending strength and are very stable. The high density gives the material special acoustic qualities. The main applications for Fasal are biodegradable packaging, toys, musical instruments and car interiors.
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BIO-based Materials
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Megawood Megawood is the brand name for a material composed of up to 75% renewable raw materials (wood particles) and about 25% polymers and additives. It is mold resistant, extremely robust and is thus suitable for barefoot decking for patios, balconies and gardens. The material requires little maintenance. Only timber from regional sources is used in its manufacture.
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Kupilka In Finland this is the name given to multipurpose vessels made from 50% wooden fiber and 50% polymers. Compared with plastic, Kupilka products are more heat resistant (-30 to +100°C); they are also more hygienic and stable than wood. The products can be shredded and injection molded again. Personal laser inscriptions are also possible.
Shoe with heel made of liquid wood (Source: Tecnaro)
WPC patio decking (Source: Kovalex ®)
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Fibrolon This name embraces a range of WPC products. These can be injection molded, compression molded or extruded. There are versions with wood-like rigidity, mechanical stability and heat resistance. The wooden fibers come from European softwood timber. Composites based on a PLA matrix are 100% biodegradable. Components made of liquid wood (Source: Tecnaro)
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Werzalit Werzalit consists of wood particles that are firmly integrated in a matrix. In the manufacturing process the plastic is first melted, after which the wood particles are added and subsequently pressed into shape. There are many semi-finished products made of Werzalit already on the market.
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Other WPC brands include Xylomer , Ecogehr WPC, Kovalex , or Thermofix .
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Fibrowood automobile interior featuring wood fiber mats with acrylic resin binder (Source: Johnson Controls)
184 Sustainable production processes
Cogwheels made by metal injection molding (Source: Arburg)
Previously, the production of large-scale sheet metal required expensive forming tools, which meant small numbers of complex-shape components could not be manufactured economically by deep drawing or stretching. For this reason, researchers in the tool machine laboratory at RWTH Aachen University developed a process that now makes this possible.
Application and processable materials
In principle, metal injection molding can be used for all metals and alloys that can be sintered. These include stainless steels as well as aluminum and copper alloys and precious metals. The biggest advantage over other processes is the possibility of producing highly complex molds in just one manufacturing step. Typical applications are casing for watches and parts for electrical appliances. The process is also used in the vehicle and aircraft industries, as well as in medical technology.
Properties  shaping of large-scale sheet metal // CNC-controlled shaping head // transfer of CAD data to the part // high reproduction accuracy // less expense for manufacturing tool molds Sustainability aspects  less manufacturing involved in producing sheet metal parts // low energy consumption through avoidance of high forming forces
Incremental sheet metal forming
Process sequence in incremental sheet metal forming (Source: beauvary)
Manufacturing concept
Application and processable Materials
With the new technology half the tools used in the forming process are replaced by kinematic forming, aided by universal tools. Shaping then occurs using a CNC-controlled shaping head, which partially reshapes the sheet in three dimensions. In this way the tool transfers the digital CAD product data onto the part. Flexible controlling even makes it possible to manufacture complexshape components without lengthy lead times. High reproduction accuracy, constant quality and low manufacturing costs are further advantages the process offers.
Sheet metal parts are used in lightweight structures in many areas of technology. Given the high degree of design leeway they offer, they are also frequently the base for several products’ brand image. As such, alongside classic applications in mechanical engineering, incremental sheet metal forming provides numerous opportunities in architecture and interior design. It can just as well be used for facade elements as it can for furniture finishes and wall elements for interior fittings, and it can be used for all typical materials in sheet metal parts.
Using high pressure to inflate hollow bodies is unusual with metallic materials. The automotive industry uses hydroforming processes to produce pipe profiles for exhaust systems efficiently. Since 2008, the Polish architect Oskar Zieta’s free inflating system has offered architects and fashion designers new potential uses.
185 Sustainable production processes
Properties customized sheet metal parts form the base // forming under pressurization // accuracy of 0.1 mm possible // furniture and lightweight architectural structures Sustainability aspects efficient production process for lightweight structures // avoids costly assembly stages
Free hydroforming Inflating process (Source: Oskar Zieta)
Manufacturing concept
Sheet metal parts that have been accurately cut on a laser cutting machine and then welded together at the edges form the starting point for the process. Air (or water) is then introduced at high pressure (up to 7 bar) through a valve, which forms the sheet metal and slowly creates a 3D body. Depending on the geometry, duration and pressure, the deformation process turns out differently. Special contouring of the sheet metal ensures that kinks form in certain areas, while in others load-bearing, cushion-like volumes that are accurate to one tenth of a millimeter emerge.
“Chippensteel” Chair collection (Source: Oskar Zieta)
Architectural trade fair stand at the 2010 IMM in Cologne (Source: Oskar Zieta; ph.: gee-ly)
Application and processable materials
The process is suitable, for example, for producing molds for the furniture industry without elaborate tools and stamps. In 2008 a stool named “Plopp” appeared on the market. A bench, a table frame and a lamp have also already been produced using the process. Oskar Zieta, who developed free hydroforming, is now planning to transfer the manufacturing principle to other areas and to produce lightweight structures for architecture (for example, for bridge construction). Tests have already been conducted on rotors for wind power plants and structures for passenger cabins. The first trade fair stand to be made of inflated structures was unveiled in January 2010, at the IMM fair in Cologne.
Clothes comb made using free hydroforming (Source: Oskar Zieta)
Ladder made using free hydroforming (Source: Oskar Zieta)
Production process for a bridge element (Source: Oskar Zieta)