Im22018en

Volume 2 2018

Exoskeleton Ceramic Tectonics Tile Grid Shell Material Xperience 2018 Print your city TUM-experiments with 3D printed (wood) concrete Research: Embracing Entropy in the Design of New Materials

I N T E R N A T I O N A L

E D I T I O N

CONTENT Innovatieve Materialen Aboutis een vaktijdschrift gericht op de civieltechnische Innovatieve Materialen sector en bouw. Het bericht over ontwik(Innovative Materials) is a digital, kelingen op het gebied van duurzame, inindependent magazine novatieve materialen en/of de about toepassing material the fields of daarvaninnovation in bijzondereinconstructies.

engineering, construction (buildings, infrastructure and industrial) and Innovatieveindustrial Materialendesign. is een uitgave van Civiele Techniek, onafhankelijk vaktijdschrift voor civieltechnisch ingenieurs werkzaam in de grond-, weg- en waterInnovatieve Materialen has bouw en verkeerstechniek.

entered partnerships with several intermediate and De redactie staatorganisations open voor bijdragen universities, allUactive in the field of van vakgenoten. kunt daartoe contact materialmet innovation. opnemen de redactie.

More information (in Dutch): www.innovatievematerialen.nl A digitalUitgeverij subscribtion in 2018 (6 editions) costs € 39,50 (excl. VAT) SJPofUitgevers Members KIVI-leden and students: Postbus € 25,(excl.861 VAT) 4200 AW Gorinchem tel. (0183) 66 08 08 Publisher e-mail: info@innovatievematerialen.nl SJP Uitgevers www.innovatievematerialen.nl

Postbus 861 4200 AW Gorinchem Redactie: tel. +31 183 66 08 08 info@innovatievematerialen.nl Bureau Schoonebeek vof Hoofdredactie: Gerard van Nifterik

Editor

Gerard van Nifterik

Advertenties Advertizing & Drs.sponsoring Petra Schoonebeek

Drs. Petra Schoonebeek

e-mail: ps@innovatievematerialen.nl

Innovative Materials

Een digitaal abonnement in 2016 (6 uitgaven)platform: kost € 25,00 (excl. BTW)

Dr. ir. Fred Veer, prof. Ir. Rob

(Glass & Transparency Zie Nijsse ook: www.innovatievematerialen.nl

Research Group, TU Delft), dr.

Bert van Haastrecht (M2I), prof.

NietsPoelman, uit deze uitgave mag worden Wim dr. Ton Hurkmans verveelvuldigd en of openbaar worden (MaterialDesign), prof.dr.ir.

Jos door middel van herdruk, fotokopie, miBrouwers, (Department of the crofilm of op welke wijze dan ook, zonder Built Environment, Section Building voorafgaande schriftelijke toestemming Physics andvan Services TU Eindhoven), de uitgever. prof.dr.ir. Jilt Sietsma, (4TU.HTM/ Mechanical, Maritime and Materials Engineering (3mE)

NEWS 1 ‘Super wood could replace steel’ 8 Exoskeleton 10 Ceramic Tectonics Tile Grid Shell 12 Material Xperience 2018

From 13 - 15 March this year the 13th edition of Material Xperience took place in Ahoy Rotterdam. With more than 8,400 visitors (a growth of over 35% compared to the previous time), 140 exhibitors and 9,000 m2 of surface area, according to organizer Materia, it is the largest multisectoral materials fair in the world. Visitors of the Materal Xperience were confronted with the latest material innovations. A random selection.

22 Print your city

During the Material Xperience the so called XXX bench, created by The Print Your City!-project was exhibited. With their project Print Your City!, research and design studio The New Raw, founded by Panos Sakkas and Foteini Setaki, recycles plastic waste into public furniture.

24 TUM-experiments with 3D printed (wood) concrete

Concrete components are traditionally made by casting. But the mould needed places significant limitations on design possibilities. 3D printing now provides new freedom in shaping. Worldwide , research is now being done into the possibilities of this relatively new concrete forming technique. Scientists at the Technical University of Munich (TUM) are experimenting with various processes, including selective binding and a new extrusion method to print a mixture of wood and concrete, generating a new material: lightweight, 3D-printed wood-concrete.

28 Research: Embracing Entropy in the Design of New Materials

A common approach to designing a complex material is energy minimization.

Like a ball in a cup, molecules at the microscale prefer to move into low-energy states. This logic can be used, for example, to design an assembly recipe for a material out of several different ingredients. In other cases, a material is designed to adapt at the molecular scale when it is strained or stimulated by e.g. light, heat, electricity, or breakage. Adaptations that we are currently able to build into a material include microscopic self-healing, stiffening, softening, shape change, light emission, opacity change, and colour change (among others). These are often designed to occur via an energy-minimising molecular pathway when the material is strained or stimulated.

Cover: 3D geprinted concrete structure, TU München (pag. 24)

NEWS

‘Super wood could replace steel’ Engineers at the A. James Clark School of Engineering, University of Maryland in College Park (USA) have found a way to make wood more than ten times stronger and tougher than before, creating a natural substance that is stronger than titanium alloy.

According to the researchers this new way to treat wood makes it twelve times stronger than natural wood and ten times tougher. It could be a competitor to steel or even titanium alloys, it is so strong and durable. It’s also comparable to carbon fiber, but much less expensive.

It takes ten times more energy to fracture than natural wood. It can even be bent and molded at the beginning of the process The team’s process begins by removing the wood’s lignin, the part of the wood that makes it both rigid and brown in color. Then it is compressed under mild heat, at about 65 °C. This causes the cellulose fibers to become very tightly packed. Any defects like holes or knots are crushed together.

The scientists found that the wood’s

fibers are pressed together so tightly that they can form strong hydrogen bonds. The compression makes the wood five times thinner than its original size.

The team also tested the material by shooting a bullet-like projectile at it.

Unlike natural wood, which was blown straight through, the fully treated wood actually stopped the projectile partway through.

According to the scientists, the material could have a tremendous potential for a broad range of applications where high strength, large toughness and superior ballistic resistance are desired. This kind of wood could be used in cars, airplanes, buildings –-any application where steel is used.

This work was published in Nature, 2018, ‘Processing bulk natural wood into a high-performance structural material’, J Song, et al. DOI: 10.1038/nature25476 More at the University of Maryland> Article online>

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NEWS

Ultrafine fibers with exceptional strength strongest fiber materials, such as Kevlar and Dyneema.

Compared to carbon fibers and ceramic fibers, which are widely used in composite materials, the new gel-electrospun polyethylene fibers have similar degrees of strength but are much tougher and have lower density. That means that, pound for pound, they outperform the standard materials by a wide margin.

According to the researchers involved, these results might lead to protective materials that are as strong as existing ones but less bulky, making them more practical. And they may have applications the scientists haven’t thought about yet.

MIT>

Left. New ultra-fine fibers created by the MIT team are seen in a Scanning Electron Microscope (SEM) image (Courtesy of the researchers)

Researchers at MIT have developed a process that can produce ultrafine fibers - whose diameter is measured in nanometers - that are exceptionally strong and tough. These fibers, which should be inexpensive and easy to produce, could be choice materials for many applications, such as protective armor and nanocomposites.

The new process, called gel electrospinning, is described in a paper by MIT professor of chemical engineering Gregory Rutledge and postdoc Jay Park. The paper appears online and is published in the February edition of the Journal of Materials Science.

The process uses a variation of a traditional method called gel spinning but adds electrical forces. The results are ultrafine fibers of polyethylene that match or exceed the properties of some of the

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A diagram of the device used to produce the fibers shows a heated syringe (left) through which the solution is extruded, and a chamber (right) where the strands are subjected to an electric field that spins them into the highest performing polyethylene fibers ever made (Courtesy of the researchers)

NEWS

HĂŠt expertisecentrum voor materiaalkarakterisering.

Integer, onafhankelijk, objectief onderzoek en advies. ISO 17025 geaccrediteerd.

Wij helpen u graag verder met onderzoek en analyse van uw innovatieve materialen.

Bel ons op 026 3845600 of mail info@tcki.nl www.tcki.nl

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09-05-17 13:19

Materials 2018 Trade fair and congress

Materials are at the base of everything we see around us. They are often taken for granted, but where would we be without our cars, machines, and buildings without a strong base? We almost forget how special materials are and how complex the selection, creation and production processes are. Not to mention about developments and innovations within these fields.

On May 30 and 31 2018, the 6th edition of Materials will take place at the NH Conference Centre Koningshof in Veldhoven, the Netherlands. During these two days, Materials will be the largest meeting point for material specialists, product developers and engineers. An all-in-concept will be presented, based on the 4 elements for finding a solution for material challenges:

Visit www.materials.nl>

Materials 2018, trade fair & congres: 30 en 31 mei 2018, Veldhoven, The Netherlands

CLICK HERE FOR YOUR FREE TICKET! 3 | INNOVATIVE MATERIALS 2 2018

Advertorial NEWS

Tecnargilla reinforces its promotional campaign abroad The exhibition’s organisational staff are focusing on foreign promotion thanks to collaboration with major partners in Spain, India, Turkey and China

The activity of the promotional campaign for Tecnargilla (Rimini 24–28 September 2018), the world’s most important exhibition in terms of ceramics and brick supplies, maintains its relentless pace, abroad above all, with the aim of ensuring an even more international edition with leading players in the

sector.

In addition to attending the main international exhibitions with a promotional staff and stand, to direct contact with the most important ceramic industry associations, chambers of commerce and outstanding buyers, foreign promotional activity this year is also supported by a

qualified network of agents who, from their respective countries, work to boost the visibility of the exhibition.

GPE Fairs in Spain, Bee2Bee in Turkey, Arta Group in Iran, Unifair Exhibition Service with its Chinese office and the Indian Rare Tech Projects Pvt are the partners Tecnargilla has chosen to extend the promotional activity abroad, where positive feedback is already being received. For this edition too, many delegations and profiled buyers are expected to enhance the ‘business meeting’ area (more than 1,000 meetings were held in 2016) particularly appreciated by the exhibiting companies for the excellent commercial opportunities.

Thanks to the intense organisational activity, Tecnargilla is even now promising further growth compared to the already significant results achieved in 2016, due both to the extensive and innovative technological offering from a gathering of companies from among the most qualified on the national and international market and to the visitor forecast, expected to exceed that of the previous edition, when there were more than 16,764 foreign visitors. http://en.tecnargilla.it>

Tecnargilla Tecnargilla is the world’s most important exhibition in terms of ceramics and brick supplies. Organised by Acimac (Association of Italian Manufacturers of Machinery and Equipment for Ceramics) and IEG Italian Exhibition Group, the exhibition offers the best of innovation in aesthetics and processes for the sector every two years, playing host to all the leading companies and attracting a great number of international buyers to Rimini.

Tecnargilla was the exhibition with the most visits from international operators in its 2016 edition too: 16,764 (+6.3 on 2014) foreign buyers from a total of 33,395 visitors (+4% on 2014). Tecnargilla welcomed 430 exhibitors in 2016 (40% of which from around 26 countries) covering an area of 80,000 m² (+7% on the 2014 edition) approx., divided into four exhibition sections: Tecnargilla, dedicated to technologies for ceramic tiles, sanitaryware and tableware; Kromatech, the showcase for colour and creativeness in ceramics; Claytech, the section dedicated to technologies for bricks and T-White the new exhibition area dedicated to the production of machinery and plants for the production of ceramic sanitaryware and tableware.

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NEWS

Durable wood carbon sponge Engineers at the University of Maryland, College Park (UMD) have for the first time demonstrated that wood can be directly converted into a carbon sponge capable of enduring repeated compression and other extreme mechanical conditions. The UMD engineers’ wood carbon sponge overcomes several limiting factors of other lightweight, compressible carbon sponges because it is simpler, less expensive, and more sustainable to produce. The new sponge can be used in various applications such as energy storage (e.g., batteries), pollutant treatment, and electronic devices and sensors.

A paper about the research was published March 1 in the journal Chem.

A team lead by Liangbing Hu, associate professor of materials science and engineering at UMD’s A. James Clark School of Engineering achieved a bendable yet resilient architecture of the wood carbon sponge by using common chemicals to destroy the stiff hemicellulose and lignin fibers that maintain the normal cell-wall structure of balsa wood, then heating the treated wood to 1,000 °C in order to turn the

organic material into carbon alone. The net effect of the process was to collapse the repeated, regular, rectangular pockets typical of the microstructure of balsa and other woods and replace them with a stack of wavy, interlocking, arch-like carbon sheets, likened to a cross between a coiled spring and a honeycomb.

According to Hu, the process for creating the wood carbon sponge is unique because the structure of the wood has been preserved. This makes the sponge highly compressible and resistant to stress. This means, according to Hu that the performance of his wood carbon sponge is one of the best among all lightweight and compressible carbonaceous materials ever reported.

After conducting further mechanical and electrical tests on the sponge, the researchers were able to incorporate a slice of it into a strain sensor prototype suitable for attachment to a human finger, a quality desirable for use in wearable fitness or health-monitoring electronics.

wood carbon sponge could also be incorporated into water purification devices and energy storage and conversion technologies, such as supercapacitors and rechargeable batteries.

More Information: Chem, Chen et al.: ‘Scalable and sustainable approach toward highly compressible, anisotropic, lamellar carbon sponge.’ DOI: 10.1016/j. chempr.2017.12.028 More at the Universityof Maryland, College Park>

Video

The researchers believe that the

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NEWS

RapidRetain wins NRK Award On March 7, 2018, during the Evening of the Manufacturing Industry in Media Plaza in Utrecht, the NRK Awards Sustainable Products 2018 were presented.

(NRK is the The Dutch Federation of Rubber and Plastics Industry) The submitted products were tested at all four phases of the product life cycle: raw materials, production, use, reuse/recycling.

Lankhorst Engineered Products won the Award in the Construction & Infrastructure category with the KLP RapidRetain quenching system. According to the jury, this innovative product fits perfectly in a circular economy.

According to Lankhorst, KLP RapidRetain System presents a sustainable and cost efficient solution for retaining walls.

KLP RapidRetain System consists of KLP RapidRetain panels and KLP RapidRetain combi-poles. According to Lankhorst the design of this high strength retaining wall system provides savings on both labour costs by faster turnaround times in installation and lower purchasing costs by efficient use of materials. With the sophisticated design Lankhorst says to unite aspects that can already be found

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independent of each other in existing retaining solutions, but never before combined in one product.

The plastic retaining wall panels are tough enough and stiff enough to be pushed into soil by crane. The KLP RapidRetain panel coupling is made strong, so that no pole is needed directly in front of each connection. The result is that all poles can be placed in one go and subsequently the retaining wall panels can be placed in one go, which translates to faster turnaround times and therefore savings. The KLP RapidRetain panel has a length of 2.1 m and is light in weight. This makes it easy to handle and efficient to place. Poles can be placed as far apart as 1 m centre to centre.

nably managed forests.

As the KLP river bank protection products are made from recycled materials, waste streams such as bottle caps, crates and agricultural film can be turned into new products with a long life. Lankhorst makes products that do not emit any substances to the environment, do not rot, nor are they affected by UV radiation, oil or solvents. The minimum technical lifetime of our recycled plastic products is 50 years during which they practically require no maintenance.

KLP plastic can easily be sawn, drilled, planed, nailed, stapled and screwed.

More at Lankhorst> Brochure (pdf download)>

Plastic retaining wall systems

The KLP Combi-post consists of an untreated timber pole that is moulded together with KLP plastic. According to Lankhorst this has the distinct advantage that no decay occurs in the air-water line, leading to a totally maintenance free solution. The wood that is used is PEFC certified and originates from sustai-

Video KLP RapidRetain

NEWS

Fire safety of innovative geopolymerbased building materials December 2017 the board of the NWO Domain Applied and Engineering Scien­ ces has granted six projects within the High Tech Materials programme, among which the project ‘Fire safety of innovative geopolymer-based building materials’ (main applicant: prof.dr.ir.

H.J.H. Brouwers and dr. Yu, Eindhoven University of Technology). This research aims to develop innovative inorganic fire resistant and thermal insulating geopolymeric coatings and structural concrete elements, and will be carried out by a PhD student and a postdoc. The external project partners are Fire Service Netherlands, Rockwool Group, M2i, Mineralz, Nieman Group and Kijstra Beton.

Geopolymeric binders, as an alternative to traditional Portland cement, have

the potential to meet contemporary functional requirements concerning high sustainability and an intrinsic excellent thermal and fire resistance. This current project aims at developing an eco-friendly inorganic geopolymeric binder for fire-resistant concretes and coatings, based on an alternative silica source.

The first step of the research addresses an alternative eco-silica source (here an olivine nano-silica) including its synthesis, colloidal silica preparation, alkali activator characteristics and reaction kinetics. The second phase will be focusing on characterization of solid precursors from industrial by-products including fly ash, paper sludge fly ash and steel converter slags. Their suitability as precursor for geopolymeric binders will be assessed. An advanced 3D cement hydration

model CEMHYDR3D will be adopted and modified to describe the reaction kinetics.

The third step is to study the geopolymerization process and thermal-physical performance, and an comparative study will be carried out using contemporary insulation materials. The fourth step is to investigate the engineering application of these new nano-engineered materials, used both in fire resistant coatings and concrete elements. The bonding behaviour and compatibility between the new material and other materials will be addressed in detail. Hence, the thermal-mechanical properties of the geopolymer-based materials are investigated from micro to macro-level.

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NEWS

Exoskeleton At the end of 2017, 43 young engineers competed for the socalled ie-net prizes 2017, the award of the Belgian engineering association ie-net for best master thesis in engineering sciences, divided into bio, civil and technology engineering. In addition, a press award, an audience award and a prize for the ‘Best Young, Entrepreneurial Engineer’ were also awarded. Five master’s theses from the faculty engineering sciences and architecture, Gent University, were selected by ie-net as the best master’s theses in engineering sciences and one of them

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- Exoskeleton, designed and constructed

by Silke van Geeteruyen and Thibaut Van Dousselaere - won the Public Award.

‘Exoskeleton’ is a pavilion, made of modular woods, tie straps and sliding joints, and shows how Computer Aided Manufacturing can create rapid prototypes. This manufacturing process allows for real-scale construction and experimentation with limited resources.

The Exoskeleton is the result of a master dissertation, that aimed to investigate a ‘bottom-up’ approach to structural design by means of prototyping, a subcate-

gory of digital fabrication. The design of a small pavilion, the Exoskeleton, served as a test case.

Bottom-up

The ‘bottom-up’ approach allows for working in an empirical way; new ideas are validated through immediate physical testing of their constructional behaviour. In this way the total design does not arise from an overarching 3D-model, deriving its components from the overall shape, but from an iterative design process instead, whereby first the com-

NEWS ponents and only then the overall shape are determined through prototyping.

As a consequence of the bottom up design approach, Van Geeteruyen and Van Dousselaere ultimately designed a parametric system rather than a single pavilion. By applying the same assembly system to the designed modules with varying dimensions, different surfaces can be generated. According to the researchers, a bottom-up design approach for structural design offers great advantages, making it an indispensable approach for the design and investigation of innovative structural principles for which no extensive previous knowledge exists.

This text is based on the master dissertation abstract. The full text dissertation is available online> Lead Architects: Thibaut Van Dousselaere & Silke Van Geeteruyen Team: Willem Bekers, Sebastiaan Leenknegt, Ruben Verstraeten, Arthur De Roover (University of Ghent, Department of Architecture and Urban Planning ), Jan Belis (Department of Structural Engineering), Stijn De Mil (Fablab Factory) Location: Ghent, Belgium Year: 2017 Area: 20 m2 Photography: Jeroen Christiaen & Saskia De Mol

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NEWS

Ceramic Tectonics Tile Grid Shell Researchers and students in the Material Processes and Systems Group (MaP+S) at Harvard Graduate School of Design created the world’s first all-ceramic grid shell, which was on display in Valencia, Spain, last february at Cevisama 2018.

Developed by researchers and students from the Material Processes and Systems (MaP+S) Group at the Harvard Graduate School of Design, Ceramic Tectonics: Tile Grid Shell explores the structural capabilities of thin, large format ceramic tiles a product commonly used as an interior surface finish or exterior cladding. The prototype is the world’s first all-ceramic grid shell.

Ceramic tiles

Structural applications are emerging as new applications for tiles, challenging age-old perceptions of ceramic as

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NEWS

surface finish. Ceramic Tectonics asks the question; can a product typically experienced as a two-dimensional surface also define and enclose a three-dimensional space?

Fabricated from unreinforced 6 mm thick ceramic tile, the catenary form of this triangular, self-supporting grid shell is designed to minimize internal stresses and efficiently span between three points of support. The structure’s 30 ceramic ribs form a novel structural pattern of triangles and hexagons and are a world-wide first system of this kind constructed from ceramics.

Connections

The notched connections between structural ribs accommodate for a novel assembly sequence that eliminates the need for mechanical connections between intersecting ribs and allows each rib to be installed vertically from above.

The project team developed a computational approach to generate the geometry of the pavilion, discretize

the form into individual components, accommodate for assembly tolerances, and generate the toolpath geometry for each component. This digital workflow enabled the project team to quickly adjust assembly tolerances and component dimensions during the design and prototyping phase.

With a maximum interior height of 2.48m, and a span of 6 m between supports, the structure includes approximately 13.5 sqm of occupiable interior space. It consists of 462 unique elements ranging from 82 - 181cm in length. The structural depth of each element ranges from 20 - 31 cm and is determined by its location within the structure. The ceramic elements measure 107.22 sqm in total area. The structure weighs approximately 1,662 kg.

Project Director: Professor Martin Bechthold Project Manager: Zach Seibold Design Research: Yonghwan Kim, Olga Mesa, Milena Stavric Engineering: M. Bechthold (peer review: Windmill Structural Consultants) Client: Cevisama Sponsor: ASCER Tile of Spain Coordinator: ITC: Javier Mira Installation: Grupo on Market More at Harvard>

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MATERIAL XPERIENCE 2018

Material Xperience 2018

13 - 15 March this year the 13th edition of Material Xperience took place in Ahoy Rotterdam. With more than 8,400 visitors (a growth of over 35 % compared to the previous time), 140 exhibitors and 9,000 m2 of surface area, according to organizer Materia, it is the largest multisectoral materials fair in the world. Visitors of the Materal Xperience were confronted with the latest material innovations.

A random selection.

Akoesta9 Akoesta9 panel is a part of a wide product range of AkoestaCradles made by the Akoesta company (Oostzaan, The Netherlands). Akoesta9 panels are made from 100 % PET, of which 60% is recycled. Akoesta9 is an affordable acoustic panel of 9 or 12 mm which is available in many colours that can be built as elements. The panels can be very precisely made in a form.

According to Akoesta, the material is strong and durable in use, and can also be used as an creative acoustic wall covering, ceiling covering or for other creative designs. The material has an absorption value of 0.9As. Benefits of AkoestaCradles are the acoustic effect, a strong and durable employable, easy to install and recyclable. www.akoesta.com/akoestacradles/

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MATERIAL XPERIENCE 2018 contained in the material ‘captures’ certain pollutants present in the air and converts them into inert salts, helping to purify the atmosphere from smog. Additionally, the mortar is made from 80 % recycled aggregates, part of which consist of scraps taken from the cutting of Carrara marble. This creates a superior brilliance compared with traditional white cements.

Another product feature is its durability: the levels of water absorption in prefabricated elements made with BIODYNAMIC are extremely low. This is the result of its compact matrix and low porosity. www.enci.nl/nl/biodynamic Foto’s: Palazzo Italia, Mario e Pietro Carrieri

BIODYNAMIC BIODYNAMIC is a highly flowable mortar grout used for manufacturing non-structural architectural elements of complex geometry and thin section. BIODYNAMIC was used to create the entire outer surface of Palazzo Italia, designed by Nemesi & Partners, which was the iconic location at EXPO 2015 in Milan. More than 750 individual BIODYNAMIC cement panels were installed, one by one, on the external wall. Some of them were up to 80 % hollow.

The BIODYNAMIC product name is a summary of its innovative characteristics: the ‘bio’ component comes from the product’s photocatalytic properties, originating from the active ingredient TXActive. This gives the product self-cleaning and de-polluting properties. In direct sunlight, the active principle

W2 passage At Material Xperience 2018 also attention was given to the special glass stones of the Willem II passage in Tilburg, which was completed in 2016. As a new public space, the Willem II passage connects the inner city of Tilburg with the De so called Spoorzone transformation area. The walls of the passage are covered with glass building blocks, the size of which is derived from the brick sizes as applied in the area.

Van Tetterode developed especially for this bicycle tunnel a bend glass panel that allows only diffused light to pass through. The tunnel is 2 x 54 meter long. The walls are made of glass panels in stainless steel made by Fiction Factory. The light behind the panels was done by Phillips lighting. The lighting is completly interactive.

The wall has won a Dutch Design Award and was nominated for the Wienerberger Brick Award 18 Categorie: Building outside the box. https://vantetterode.nl/

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MATERIAL XPERIENCE 2018 I-MESH I-MESH is a multi-axial, yarn-oriented material. It’s the result of an experience based on the theoretical study and on the experience acquired on composite materials, mainly in the nautical and aerospace environment. It is sustainable, recyclable, noise-absorbing, insulating, non-combustible, and it guarantees energy saving.

I-MESH yarn layout can be totally customized by the I-MESH designers in close collaboration with the customer. It is constituted by different materials, chosen according to the expected function. The raw materials used have excellent flame-retardant properties, high mechanical and physical performances, excellent thermal insulation power, and they are resistant to attacks of chemical debris.

I-MESH is made in the colours: Black, White, Copper, Gold, Basalt.

The material can be produced in small size panels or in to very large panels, up to 5 x 15 meters or 5 x 12.5 meters depending on the finish. Its natural yarn colours are white, black,

grey, gold, copper for both indoor and outdoor use; but yarns can also be dyed, to offer a potentially infinite pantone for indoor applications. Its softness is a variable, depending on the material, on the yarn dimension and on the total thickness of the fabric. The names of the materials explain its technological soul - carbon fiber, fiberglass, zylon, technora and basalt. It is 6/7 times stronger than metal, has excellent fire retardancy property, and is PVC free.

More at I-MESH>

Equitone linea Equitone Linea is a 3D-shaped, through-coloured façade material, produced by Etenit NV (Kapelle-op-denBos, Belgium). The material displays a linear texture that highlights the raw inner texture of the core fibre cement material. Every moment of the day, the changing angle of the daylight gives the façade material a different aspect. As of 2018 also available in white.

More at Eternit>

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MATERIAL XPERIENCE 2018 Flax wall core

Photos: Materia/Faay

Flax is one of the oldest known textile plants in the world. It’s grown primarily for the production of linen and yarns (long fibres). It is mainly used in garments, and table and bed linens.

This production and processing process, produces various by-products: such as the medium-length fibres, short fibres and wood-like particles (flax shives). Up until the mid-Nineteen Fifties these wood-like particles were generally destroyed, but ever since then they have been pressed into solid panels.

These solid panels are used in the construction industry for the interiors of buildings, for example, in doors, kitchen worktops and partition walls. Faay uses these ‘flax straw’ panels, as a basis for their walls.

Flax is light-weight and fire-retardant. It has a tough structure and does not burn, but smoulders instead. Flax furthermore has high insulation and dB values. The flax chipboard panels are 100 % biodegradable and 100 % recyclable as part of our process. Faay’s flax walls can be supplied in various heights and thicknesses.

When it comes to sustainable building, in particular, construction materials made from renewable raw materials - such as flax - are a very interesting option. On top of that the environmental impact involved in the production of flax is low. That is because flax absorbs CO2 and converts it into oxygen while it is growing and it has a low energy content during the processing process which means its environmental impact is low. The local growing and processing of flax furthermore reduces polluting transport to a minimum.

More at Faay>

True Scale True Scale by Formica Group decors is developed for large scale applications such as feature walls in retail or hospitality environments. With this in mind, Formica Group is introducing eight True Scale marble decors that replicate the characteristics of the natural stones. Calacatta Marble for instance captures the exquisite detail of the stone’s fine translucency of intricate warm grey and soft taupe veining against striking white.

Breccia Paradiso surprises with rich colour play and beautiful scale while Slate Sequoia imitates a dark warm-toned marble with large characterful veining. Dolce Vita is reminiscent of exotic stone broken up with fine white crystalline structures of quartz. Other True Scale additions include Travertine Silver, Antique Mascarello, Blue Storm and Jet Sequoia.

Some applications for usage include: interior wall cladding, point of sale, locker rooms, paneling, cupboards, drawers, bedroom furniture, bars and counters, office/receiption desks, interior doors and work surfaces.

More at Formica>

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MATERIAL XPERIENCE 2018

Alusion Genesis PD uses Alusion aluminium foam together with epoxy, and it can also be used with ‘coloured epoxy’.

Alusion’s patented process for creating the aluminium foam starts with a metal matrix composite - an aluminium alloy to which ceramic particles have been added. Once melted, the aluminium alloy is poured into a foaming box. Gas bubbles exiting immersed rotating impellers (a

component of the air injection system) form the foam. The foam collects on the surface of the molten material, where it can be continuously drawn off to form a sheet. The foam structure is predominantly closed cell. The cell size is controlled by the gas flow rate, impeller design and impeller rotational speed. The rate and means by which the gas is introduced can be varied to produce foams with varying densities.

Liquid Gloss

The aluminium foam is poured in with so called Liquid Gloss, creating ‘air bubbles’ in the process. By adding LED lighting, Genesis PD creates special colour and lighting effects. Liquid Gloss is a transparent, syrupy two-component epoxy resin has used since 1997 as a coating in art, architecture and the catering industry.

Because of its composition and the manual casting and manufacturing process, Liquid Gloss can be used on a wide variety of objects, like furniture, such as tables and bar tops.

The aluminium foam is produced in continuously cast sheet 1.22 m wide which is cut to 2.44 m lengths. Longer lengths can be produced if sufficient quantities are required.

Text/photos: Genesis PD More at Genesis PD>

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MATERIAL XPERIENCE 2018 Structural veneer Structural veneer consists of thin-gauge Grip Metal mechanically bonded to wood veneer with some kind of metal Velcro tape. Structural Veneer is created in a collaboration of two Canadian companies, Grip Metal en Corruven.

Grip Metal is also a patented stamping process created to modify sheet metal, applying an array of micro-formed hooks that can physically adhere with other materials without the use of traditional adhesives. Diverse materials such as rubbers, plastics, wood and wood composites, concrete, carbons, glass fibers, papers, friction composite materials, and many others, can be physically adhered to Grip Metal substrates.

Corruven was founded in 2008 by forestry engineer Alain BĂŠlanger. The company makes lightweight corrugated sheets for architectural use. There are two product lines: design materials and protective packaging. The combination of the Corruven veneer and the joining technology of Grip Metal makes a thin and strong material, with a woody appearance and suitable for structural applications.

More at Corruven>

Above: Chair made of structural veneer (Corruven & Grip Metal) shown at Material Xperience 2018

Grip Metal, video

Under: Grip Metal, detail

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MATERIAL XPERIENCE 2018 yet reused in an optimal circular way. In our project we processed burlap bags from Starbucks (coffee company), woolen scrap cuttings from Ahrend, (specialist in realization of interior projects) and denim from Sympany (textile collector).

At the start of the project, these three residual textile streams are either incinerated or processed into filling or insulation materials.

Within the RECURF project various organizations cooperate. The Amsterdam University of Applied Sciences (AUAS), in cooperation with several partners, has conducted research in residual textiles. The research tried to clarify how residual textiles could be upcycled into useful circular products. The textiles were combined with biobased plastics into new materials. Given its availability and biodegradability, the bioplastic PLA was used in all three cases. These new materials were used to develop products with unique characteristics and application possibilities. During the course of the project, a great number of possible material combinations was identified.

The new materials varied in technical and mechanical characteristics and showed a wide range of different perceptive values. Based on the most favourable material combinations some prototypes were developed and tested.

More at HVA (Dutch)>

RECURF-UP While the amount of waste continues to grow, raw materials become scarcer and more expensive. The circular economy offers solutions to cope with these growing problems. Within the developing circular economy, biobased materials are on the rise and close attention is paid to reuse and recycling. New business models based on waste reuse and value creation are being developed. Research is conducted in biobased plastics, textile waste streams and bio composites, however the combination thereof has not been researched yet.

The RECURF-project of the Hogeschool van Amsterdam (HVA) aims to Re-use Circular Urban Fibres and Biobased Plastics in Urban Products.

Several companies within the Amsterdam metropolitan region generate textile waste streams. These streams are not

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MATERIAL XPERIENCE 2018

DUKTA DUKTA is a type of incision process that makes wood and engineered wood flexible. It is produced by Gommans in Venlo, the Netherlands. Because of the incisions, the material gains textile-like properties and a significantly wider range of applications. The internationally patented method works with commercial engineered wood such as plywood, MDF and three-layer boards.

According to Gommans DUKTA acoustic walls and ceilings achieve high sound

absorption across all frequencies, which are reached by other absorbing products only in specific frequency ranges. When flat installed, they are comparable with other good quality, traditional absorbers.

DUKTA wood panels are suitable for both wall and ceiling applications, as well as free-standing partitions, lighting and furniture. The regular incisions change the static structure of the panels in a fundamental way. These incisions make parts opposite the incision flexible but the material retains its static stability along the direction of the cuts.

Nearly all commercial wood-based boards can be made flexible using the DUKTA process. The various incision types: SONAR, LINAR, FOLI and JANUS, differ in terms of the appearance of the cut, the proportion of open surfaces and their flexibility.

More at Frans Gommans> ducta.com>

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MATERIAL XPERIENCE 2018

WYND Rotterdam based Studio WYND is an inter-disciplinary initiative for the designed engineering of fibrous composites with functional aesthetics to create high performance interior environments (furniture systems). These interior designs will be materially optimised yet with maximum strength for supporting the determined loads via engineering multi-layered fibre compositions.

One of their designs, a table made of carbon fibre, was displayed at Material Xperience.

With high tensile strength and low weight, carbon fibres are popular in aerospace, competition sports and the military.

Carbon fibers have several advantages including high stiffness, high tensile strength, low weight, high chemical resistance, high temperature tolerance and low thermal expansion. The designs by Studio WYND, consisting of a table, a coffee table, a bench and a chair, express the contradictory characteristics of carbon fibre as a material, such as maximum strength versus minimum self-weight. For instance, the Pure Noire series, WYND emphasis on carbon fibre’s incomparable lightness both visually observable in its porous appearance and physically tangible by its extreme light weight while optimising material usage to its maximum.

More at http://www.WYND.nl/

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MATERIAL XPERIENCE 2018

TERRA-ink: Shelters 3D printed of local soil In recent years, natural disaster and military conflicts forced vast numbers of people to flee their home countries, contributing to the migration crisis we are facing today. Focusing on temporary shelters suitable for the transitioning period between emergency accommodation and permanent housing, TERRA-ink addresses new construction methods that allow for time and cost efficiency, but also for flexibility to adapt to different contexts.

The concept was presented at Gevel 2018 (january) and Materal Experience (march).

TERRA-ink aims to develop a method for layering local soil, by implementing 3D printing technologies. The use of locally sourced materials in combination with additive manufacturing is investigated aiming at reductions in financial investments, resources and human labour, as well as at simplified logistics, low environmental impact and adaptability to different situations and requirements. Such a building system has the potential of combining lowand high-tech technologies, in order to facilitate a fully open and universal solution for large scale 3D-printing using any type of soil.

TERRA-ink is a 4TU.Bouw project (4TU. Bouw is a coalition of the four Dutch Technical Universities). The researchers involved: Tommaso Venturi, Dr. Michela Turrin MSc Arch,Foteini Setaki Msc Arc, dr.ir. Fred Veer (TU Delft); Arno

Pronk, Prof.Dr.-Ing Patrick Teuffel, Yaron Moonen, Stefan Slangen and Rens Vorstermans (Eindhoven University of Technology).

More at 4TU.Bouw>

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MATERIAL XPERIENCE 2018

Print your city During the Material Xperience the so called XXX bench, created by The Print Your City!-project was exhibited. With their project Print Your City!, research and design studio The New Raw, founded by Panos Sakkas and Foteini Setaki, recycles plastic waste into public furniture.

It was kick-started in 2016 in collaboration with Aectual as 3D Printing in the Circular City (Stimulus project of Circular City Program of AMS Institute) and supported by the Technical University of Delft, and AEB Amsterdam.

The idea was to process recycled plastic pellets from municipal plastic waste in order to 3D print street furniture and equipment. The first piece of furniture the studio made is the XXX bench, entirely made of recycled plastic and, in turn, is 100 per cent recyclable. The bench seats two to four people and has the form of a double sided rocking chair.

The XXX bench was produced in collaboration with Aectual, on a large-scale pellet extrusion 3D printer.

The project 3D Printing in the Circular City explored circular possibilities to expand the applications of recycled plastic.

Studying how to turn plastic waste into a strong printing material was a major part of the research. Local plastic waste streams are examined and assessed to define their utilization patterns and

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MATERIAL XPERIENCE 2018 recycling potential. The researchers tested a selection of materials in the laboratories of TU Delft to assess their mechanical properties. Plastics with the right mechanical properties are recycled into a material engineered specifically for 3D printing.

Platform

The 3D printed bench weighs approximately 50 kilos, which is almost equal to 1,5 times the waste produced by an Amsterdam individual in one year. Based on these numbers 650.000 benches in Amsterdam could be produced yearly.

According to the AMS Institute website, the possibilities for applications and designs with printing from recycled plastics are endless. 3D Printing in the Circular City provides a platform for the city of Amsterdam to locally build a unique public space, created from its own plastic waste, in collaboration with its own residents.

Urban furniture

According to the parties involved, XXX bench can be easily customized in shape or function and integrate personal messages or logos on it, like the logo of the city of Amsterdam. Following from XXX, the project is focusing on the development of a broader range of urban furniture and public space applications such as bus stops, recycling bins, playgrounds and anything else that city residents may need.

3D Printing in the Circular City explores the potential to provide an innovative way to reduce the municipal waste volume through recycling household plastics waste, locally with large scale 3D-printing.

More information: www.printyourcity.nl> www.ams-institute.org> www.thenewraw.org>

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Cellulair structuurelement gemaakt van lichtgewicht beton, geproduceerd door selectieve binding (Cement Activation) (foto: K. Henke, TUM)

INNOVATIVE MATERIALS 2 2018

TUM-experiments with 3D printed (wood) concrete Concrete components are traditionally made by casting. But the mould needed places significant limitations on design possibilities. 3D printing now provides new freedom in shaping.

Worldwide , research is now being done into the possibilities of this relatively new concrete forming technique. Scientists at the Technical University of Munich (TUM) are experimenting with various processes, including selective binding and a new extrusion method to print a mixture of wood and concrete, generating a new material: lightweight, 3D-printed wood-concrete.

According to Dr. Klaudius Henke of the TUM Chair of Timber Structures and Building Construction, additive manufacturing is extremely attractive for architecture and construction. It enables a wide range of shapes at high levels of cost-efficiency, even in small batch sizes.

A team lead by Dr. Henke has been

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studying 3D printed concrete, creating extremely lightweight and thin but strong pipes. The interiors of the pipes contain an intricate bracing structure which lends it its strength; material testing has shown that the pipes can withstand forces of up to 50 newtons per square millimeter, making them

just as stable as conventionally cast concrete.

The interior bracing structure would have been impossible to create using conventional techniques. To create the pipes, the TUM researchers used selective binding. Thin layers of sand are doused with a mixture of cement and

INNOVATIVE MATERIALS 2 2018 using an automatic scattering system.

A three-dimensional system of tracks makes sure the print head can be positioned at any desired point in the working space and a nozzle can apply fluid to exactly the desired points.

Success depends among other things on the thickness of the layers, the grain size of the sand, the speed at which the print head moves and the selection of the right nozzle. The engineers have optimized the various parameters together with the TUM Centre for Building Materials.

Extrusion head (photo: TUM)

water at exactly those points at which the solid structure is to be created. Once all the layers have set, the surplus sand can easily be removed, leaving only the desired concrete structure.

Details

According to TUM, the trick is in the details. First the TUM researchers had to build a selective binding unit. The over-dimensioned printer fills an entire laboratory room in the basement at the Chair’s premises. Sand is distributed

Together with partners from industry, the team is currently developing a 3D printer whose print head will be equipped with several thousand nozzles.

The device will make it possible for the first time to manufacture components with volumes of approximately ten cubic meters. Test runs are planned to begin this spring.

Wood concrete

Another alternative is the extrusion method, in which pre-mixed concrete

One of the largest test objects, which was created as part of the research project is a wall element with dimensions of 150 cm x 50 cm x 93 cm (l x w x h) (Photo: K. Henke/Technical University of Munich)

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INNOVATIVE MATERIALS 2 2018 Custom made

Extrusion head (Photo: TUM)

Using the extrusion method the TUM team has already succeeded in constructing 1.5 meter wide and 1 meter high prototypes made of lightweight wood-concrete. Lightweight wood-concrete is just as resilient and insulating as conventional gas-aerated concrete. The only disadvantage is the rough surface texture: the strands which make up the wall are readily visible.

‘This structure can be used as a design element or can be post-processed,’ says Henke. ‘The lightweight wood-concrete is also easy to saw, mill and drill.’

Henke is convinced that 3D printing will change architecture. The technology not only allows more versatile shaping, but also more variety, since each component can be individually designed without incurring any additional costs.

The research activities are being conducted in close collaboration between the Chair of Timber Stuctures and Building Construction and the Centre for Building Materials. The German Research Foundation (Deutsche Forschungsgemeinschaft/DFG) and the German Federal Ministry for the Environment, Nature Conservation,

Selective binding (Photo: TUM)

can be used. The TUM researchers have investigated and optimized this 3D printing method as well. According to Henke, the advantage is primarily in the high construction speed. The selection of material components and formation of interior cavity structures make it possible to produce multifunctional components. For example, adding wood chips, which contain a large amount of air, provides integrated thermal insulation, protecting buildings from undercooling in the winter and overheating in the summer.

The researchers at TUM have conceived and implemented an extrusion system for processing the new lightweight wood-concrete: The mixture of cement, wood and water is pumped through a nozzle, creating strands of concrete as much as approximately two centimetres thick. The nozzle is mounted on a computer-controlled robot arm that precisely places the strands on top of one another to form the desired structure.

Pipe with double bracing, made by selective binding (paste intrusion) (Photo: K. Henke / Technical University of Munich)

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INNOVATIVE MATERIALS 2 2018

At the pilot plant for additive manufacturing, a multi-functional wall element is produced. Bachelor student Bettina Saile fills the test extruder with fresh concrete (Photo: K. Henke/Technical University of Munich)

Building and Nuclear Safety (BMUB) research initiative ‘Zukunft Bau’ are providing funding to both the ongoing and recently launched research projects.

(Images: K. Henke TUM) www.tum.de Publicatie ‘Additive Fertigung frei geformter Bauelemente durch numerisch gesteuerte Extrusion von Holzleichtbeton’ online>

Video

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RESEARCH

Embracing Entropy in the Design of New Materials A common approach to designing a complex material is energy minimization. Like a ball in a cup, molecules at the microscale prefer to move into low-energy states. This logic can be used, for example, to design an assembly recipe for a material out of several different ingredients. In other cases, a material is designed to adapt at the molecular scale when it is strained or stimulated by e.g. light, heat, electricity, or breakage. Adaptations that we are currently able to build into a material include microscopic self-healing, stiffening, softening, shape change, light emission, opacity change, and colour change (among others). These are often designed to occur via an energy-minimising molecular pathway when the material is strained or stimulated. (Figure 1)

Elaborate materials can be designed, in principle, by this logic. But in practice, they often yield poor practical (experimental) success. The more complex the target structure, the more difficult it can be for the ingredients to follow the exquisite pathway leading to it. This is because the pathway is competing with “detours�: alternate routes leading to partial or incorrect structures. Detours may go energetically up-hill or down-hill,

28 | INNOVATIVE MATERIALS 2 2018

and often lead to kinetically long-lived structures that are difficult to undo.

While each detour might be a rare event, the massive number of possible detours leading away from the correct pathway can easily reduce the success rate of the assembly or response. This is particularly true for elaborate pathways that involve different intermediate structures en route to the final structure. An analogy

is to imagine a tourist driving in a car to reach their destination without a map. The chance they take a wrong turn leading elsewhere is higher if there are more turns involved in the route, simply because there are more chances to go wrong.

Entropy

The plethora of possibilities that molecules experience is called entropy. Mo-

RESEARCH lecular pathways must always contend with it. The goal of this article is to offer a suggestion (or a reminder) to find ways that we can embrace entropy, rather than fight it. Materials that have many paths of response or assembly to the final structure are more robust than those with just one or few ‘designed paths’. We can thus use entropy to our benefit for making complex materials with remarkable functions.

Materials are always in motion at the molecular scale, due to thermal energy. This gives microscopic objects possibility, allowing them to visit different configurations, conformations, permutations, or orientations besides their energy-preferred ground state. Entropy at the molecular scale is a quantification of molecular possibility. Entropy drives building blocks towards structures that have more possibilities associated with them.

‘Polymers with personality’

To date, a variety of designer polymeric materials actively utilise molecular motion to perform functions. Recent examples include materials that self-heal when damaged, dynamically adapt to strain using reversible crosslinks, or reshape and deform in response to light or local chemical environment.

These might be called ‘polymers with personality’: materials with a molecular-scale reflex. These substances adapt and change their fate at the microscale, according to their external environment or a stimulus. Molecular design encodes the personality of the material that we see at the macroscale.

These materials are inspiring for their creative use of molecular entropy. But we can go further. As a molecular architect - theoretical or experimental - the next step is to understand how entropy is dictated by composition in a material, and how this changes when the material is altered.

Inspiration from Life

Nature abounds with materials and systems where entropy is utilized for robust functionality. A practical instance for the design of polymeric materials is the way that interactions occur at cell surfaces. For example, T-cells in the human immune system interact with a target cell via many weak ligand-receptor

Figure 1: (Top) Initial ingredients evolve either spontaneously, or when simulated, to products via an assembly pathway (green) as shown schematically here. This pathway competes with a myriad of detours (red), leading to malformed structures and kinetic dead-ends. (Bottom) In a more robust molecular assembly or response process, there are more routes to reaching the target structure. Incorporating entropy into the design helps build more of these viable pathways, by taking advantage of molecular fluctuations around their energy-preferred states

bonds. This ‘multivalent’ binding paradigm causes the cell-cell adhesion to be extremely selective to the number of ligands and receptors on the T-cell and target cell. Binding is strong when the ligand-receptor density is above the threshold, yet extremely weak when below this threshold. (Figure 2) Selectivity comes from the number of possible independent ligand-receptor bonds when the two cells are in contact. The relatively weak ligand-receptor bond strength permits the system to explore these binding permutations on a short timescale. This represents an entropy that contributes to the overall adhesion strength between the two cells. The entropy contribution varies, and thus can be tuned, with the number of ligands and receptors. This level of control is absent in energy-dominated ‘monovalent’ designs. Multivalency is a powerful yet generic microscopic paradigm that has already seen applications in synthetic molecular design, but much remains to be done.

Figure 2: Multivalent nanoparticle (green) and polymer (red) interacting with a receptor-coated surface (blue). In both cases, the objects are interacting with the receptors via discrete binding groups (e.g. ligand, functional groups). The most significant multivalent entropy occurs when ligand-receptor bonds are weak, and when they can be independently bound or unbound

In general, weak molecular interactions present the opportunity for entropic design. Weak bonds have the strong benefit of reversibility on short timescales, so that mistakes along an assembly or response pathway can be undone quickly. The binding units can be designed to have specific interactions only with a subset of the molecular moieties in the system, yielding specificity. For example, two multivalent molecular entities

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RESEARCH

Figure 3. Molecular dynamics simulations are valuable tools for gaining microscopic insight into a material at equilibrium, and when deformed. Here, we are carrying out simulations of a polymer network (blue) with bonding units (yellow) on each monomer. Reversible crosslinks (red) can form one or two bonds with polymers using their own bonding units (green)

will be strongly bound only when the majority of their different binding units are chemically complimentary. If not, the binding will be weak and reversible.

ed, spatially restricted, or stretched have lower entropy than a free polymer. Manipulating the entropy of the polymers is thus another route to molecular design.

Adaptive gels

In current research with Wouter Ellenbroek and Cornelis Storm at Eindhoven University of Technology, I am studying a new material that exhibits this design.

The material, a gel, is comprised of a

For multivalent design, polymeric molecules are a promising candidate. But polymers themselves have nontrivial entropy. Polymers that are more confin-

30 | INNOVATIVE MATERIALS 2 2018

permanently-crosslinked polymer network, along with reversibly crosslinking monomers diffusing within the gel. The reversible crosslinks allow the material to be strained to a much greater extent than the native material without the reversible linkers, yet remarkably having the same native stiffness at small deformations. (Figure 3)

RESEARCH their conformations and exploring their local molecular neighbourhoods within the material. When new bonding partners are found, the network topology is changed. Energy minimization is negligible in these changes, as bonds are only swapping, and not breaking. Cooling from this entropic regime solidifies the network topology into place, bringing the system into a local energy minimum until heated again.

Figure 4: Polymers (blue) attached to a permanent crosslink (white) in a polymer network, and a reversible crosslink molecule (red) in solution nearby. The entropy cost is lower when the reversible linker binds near the permanent crosslink (upper right), as the two adjacent polymers do not lose as much configurational freedom as when the reversible link binds further away (bottom right). The binding strength for the reversible crosslinks is the same in both cases. Thus, the linkers are entropically driven to recruit around the permanent crosslinks in the network. (Note that the four polymers extend beyond the cartoon shown, ultimately attached at their other ends to other permanent crosslinks in the system.)

Through microscopic theory and modelling, we are finding that relatively weak-binding reversible crosslinks prefer to recruit around the permanent crosslinks. This is an entropy-driven phenomenon. (Figure 4) Forming a reversible crosslink far from a permanent crosslink leads to greater spatial restrictions for the two polymer chains involved in the link. This leads to lower entropy. On the other hand, entropy loss is smaller when placing the reversible crosslink near a permanent crosslink, where the two polymers are already quite restricted.

an operational example. Vitrimers are polymer networks, containing polymer chains connected together by strong crosslink bonds. The material is strong and elastic at low temperature, yet can be reshaped at high temperature for self-repair and recycling.

By recruiting near permanent crosslinks during strain, the reversible linkers serve only to strengthen the former without altering the polymer network topology.

This leads to the uniqueness of the material: it is far tougher, but with the same stiffness as the native gel without the reversible linkers.

This mechanism is based on an exchange principle that allows the crosslinks in the network to be exchanged, but not broken. As a result, the total number of crosslinks is constant; however, the exchanges give the material deformability that is comparable to that of molten glass: easily workable, deformable, and recyclable. Activation of the exchange mechanism is done by raising the temperature, which makes the analogy with molten glass a bit stronger. Various chemical realisation of this principle have been developed in recent years, for example the use of transesterification reactions to make ester crosslinks in networks dynamic.

Vitrimers

Swapping, not breaking

Materials can also be designed to harness the intrinsic molecular entropy of the polymers themselves. A unique class of materials called ‘vitrimers’ provides

Using entropy in materials design requires microscopic insight, for which molecular theory and simulation are valuable assets. Active research in this area seeks to define clear links between microscopic design, and the unique often unexpected - material responses that result. This research is alluring for industry and academia alike, due to the diversity of possible microscopic designs that can be harnessed for new applications or fundamental physical insight.

Nicholas B. Tito In cooperation with Wouter G. Ellenbroek and Thijs van der Heijden, Mathijs Vermeulen and Anwesha Bose.

Theory of Polymers & Soft Matter, Department of Applied Physics Eindhoven University of Technology Eindhoven, The Netherlands Email: nicholas.b.tito@gmail.com ‘Self-Consistent Field Lattice Model for Polymer Networks’ door dr. Nicholas B. Tito, dr. W. Ellenbroek en prof.dr. Kees Storm (TU/e).

[Macromolecules, 2017, 50 (24), pp 9788–9795] Parts of this research have been performed within the framework of the 4TU. High-Tech Materials research programme ‘New Horizons in designer materials’ (www.4tu.nl/htm). The page for the project can be found here: https://www.4tu.nl/htm/en/new-horizons/reversible-crosslinking/

The ability of the material to be reshaped at high temperature relies on polymer entropy. All of the polymers are in motion in the liquid state, changing

31 | INNOVATIVE MATERIALS 2 2018

AGENDA Plastics Recycling Show 24 - 25 april 2018, Amsterdam www.prseventeurope.com/

Biopolymer 19 - 20 juni, Halle, Duitsland https://polykum.de/en/biopolymer-2018/

Hannover Messe 23 - 27 april 2018, Hannover http://www.hannovermesse. de/home

15th International Conference on Inorganic Membranes 18 - 22 juni 2018, Dresden https://www.icim2018.com/

Intermat 2018 23 - 28 april 2018, Parijs https://paris.intermatconstruction.com/

Holz messe 29 aug-1 sept 2018, Klagenfurt www.kaerntnermessen.at

Ceramics Expo 2018 1 - 3 mei 2018, Cleveland www.ceramicsexpousa.com

Architects@work 12 - 13 september 2018, Rotterdam www.architectatwork.nl

Bio-based Materials 15 - 16 mei 2018, Keulen bio-based-conference.com

Aluminium Next 20 september 2018, Veldhoven mikrocentrum.nl

Challenging Glass 17 - 18 mei 2018, Delft www.challengingglass.com

Tecnargilla 2018 24 – 28 september 2018, Rimini, Italië http://en.tecnargilla.it//

Biocolours 28 - 29 mei 2018, Breda bio-oloursconference.com

Kunststoffen 2018 27 - 28 september 2018, Veldhoven https://kunststoffenbeurs.nl/

LIMA, Leichtbaumesse 29 - 30 mei 2018, Chemnitz, www.lima-chemnitz.de/

Aluminium 2018 9 - 11 oktober 2018, Düsseldorf www.aluminium-messe.com

Utech Europe 29 - 31 mei 2018, Maastricht http://www.utecheurope.eu

Nationale Staalbouwdag 2018 10 oktober 2018, Amsterdam nationalestaalbouwdag.nl/

Materials 2018 30 - 31 mei 2018, Veldhoven www.materials.nl

Industrietag Siliciumnitrid 23 - 24 oktober 2018, Dresden www.ikts.fraunhofer.de

Materials Science and Engineering 11 - 13 juni, 2018 Barcelona

Metavak 2018 30 oktober - 1 november 2018, Gorinchem

Cements 2018 11 - 12 juni 2018, USA ceramics.org/cements2018

Composites Europe 6 - 8 november 2018, Stuttgart www.composites-europe.com

Biobased Performance Materials (BPM) 14 juni 2018, Wageningen

XVI ECerS Conference 16 - 20 juni 2019, Turijn http://ecers.org/

Voeg informatie toe aan de Kennisbank Biobased Bouwen De Biobased Economy speelt een belangrijke rol in de duurzame ontwikkeling van Nederland en biedt nieuwe kansen voor het bedrijfsleven. Via de kennisbank kunt u kennis vergaren en delen over de beschikbaarheid en toepassingsmogelijkheden van biobased materialen, producten en bouwconcepten. Samen versterken we zo de biobased economie.

Ruim dertig partijen in de bouwsector ondertekenden de green deal biobased bouwen. Deze producenten, architecten, adviseurs en kennisinstellingen delen hun kennis rond kansrijke mogelijkheden van biobased bouwen. Ook de ministeries van Binnenlandse Zaken (Wonen en Rijksdienst), Economische Zaken, en Infrastructuur en Milieu ondersteunen de green deal.

Bouw ook mee aan de biobased economie en voeg uw project- of productbeschrijvingen toe aan deze kennisbank.

Kijk op www.biobasedbouwen.nl voor meer informatie>

INNOVATIVE MATERIALS Innovative Materials Innovative Materials provides information on material innovations, or innovative use of materials. The idea is that the ever increasing demands lead to a constant search for better and safer products as well as material and energy savings. Enabling these innovations is crucial, not only to be competitive but also to meet the challenges of enhancing and protecting the environment, like durability, C2C and carbon footprint.

By opting for smart, sustainable and innovative materials constructors, engineers and designers obtain more opportunities to distinguish themselves.

As a platform Innovative Materials wants to help to achieve this by connecting supply and demand. info@innovatievematerialen.nl

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