Den höga miljöpåverkan från textilfärgning och efterbehandling, på grund av hög vattenförbrukning, dess förorening, och ineffektiv användning av energi, är idag välkänt. För att minska miljöpåverkan föreslår forskningsvärlden användning av färgämnen från naturliga resurser. Syftet med att använda dessa är att ge nya attribut till textilier utan att göra avkall på miljömässig hållbarhet. Attribut som ges kan vara färg och/eller andra egenskaper. En nackdel är dock att användningen av bio-baserade färgämnen är inte fri från att belasta miljön. Det blir därför av största betydelse att bedöma denna miljöpåverkan och förbättra miljöprofilen. Sådana studier är dock i allmänhet sällsynta.

Studien som presenteras i denna avhandling har inkluderat miljöpåverkans- bedömning, med hjälp av livscykelanalys (LCA), i designprocessen av en multifunktionell polyester (PET) väv via naturliga antrakinoner. Genom att göra så har ett eko-design tillvägagångssätt använts, med avsikt att bana väg för miljömässigt hållbar bio-funktionalisering av textil.

Antrakinonerna erhölls från rot extrakt av växten krapp (Rubia tinctorum L.), och hänvisas till som krapp färgämne. Frågeställningar var därför formulerade relaterat till användningen av krapp färgämne. Tre forskningsfrågor har besvarats: (I) Kan krapp färgämne verka multifunktionellt på en PET väv? (II) Hur ser miljöprofilen ut, från färgningsprocessen av PET med krapp färgämne, och hur kan den förbättras? (III) Vilka är de största utmaningarna med att använda LCA för att bedöma miljökonsekvenserna av textilfärgning med växtbaserade färgämnen?

Det kan konkluderas att det finns potential för krapp färgämne att verka multifunktionellt på PET. Baserat på uppmuntrande resultat är en rekommendation för det framtida arbetet att fokusera på kvalitén hos de attribut som presenterats och deras förbättringspotential, både i färgning via färgbad och via foulard. LCA driven processoptimering av textilfärgningen förbättrade i varje miljöpåverkans- kategori som studerats. Emellertid har flera utmaningar identifierats som måste 

övervinnas för att LCA skall kunna bidra till en hållbar användning av multifunktionella växtbaserade färgämnen för textil. De största utmaningarna är bristen på tillgängliga data i forskningsstadiet och den tvärvetenskapliga forskningsarenan. Det är tänkt att om dessa utmaningar bemästras kan LCA bidra till en hållbar bio-funktionalisering av textil.

The demand for textile fibres is growing quickly. However, global cotton production has stabilized around 25 Mton/year. This is a sound development since cotton cultivation causes major sustainable development issues. Even if regenerated cellulose fibre production steadily grows, it is still only from a sixth to a fifth of cotton volumes. Hence, it is essential to find resource-efficient routes to generate alternatives to virgin cotton. There are many promising research initiatives that discover the possibility to utilize waste streams of neat cotton and cotton in fibre blends as raw materials for dissolving pulp for regeneration into, for example, viscose or Lyocell. However, there is a much simpler and energy-efficient route at hand. If fabrics are disintegrated mechanically, the separated fibres can be turned into yarn again. However, since fibre length is a key parameter to accomplish strong and durable textiles, fibre length loss upon tearing should be minimized. This study evaluates how fibre length distribution alters upon tearing of post-consumer cotton waste of two different constructions: denim and single jersey; and different degrees of wear, rendering four different fractions: (1) barely worn denim, (2) rather worn denim, (3) barely worn single-jersey and (4) rather worn single-jersey. Before tearing, the garments were dissembled, their yarns were characterized, fibre length distributions were manually determined for (1)–(4). Length analysis of the recovered fibres after tearing revealed that the length drop was most severe for (a) the finer single-jersey and (b) the barely worn fractions. The findings suggest that significant wear does not exclude from mechanical recycling.

Description

Advances in Textile Biotechnology, Second Edition examines the latest in biotechnology for the fiber and textile industry. This new edition has been fully revised to include the current essential areas of development in the field, covering both natural and synthetic fibers. Chapters cover the latest technology in bioprocessing for bast fiber, PVA, polyester, wool and silk before exploring issues of enzyme stability. Essential areas of application and development are then considered, including biomedical textiles, silk materials for biotechnological applications, bacterial cellulose, the ink jetting of enzymes, and the role of enzymes, wool and silk fibers.

Containing groundbreaking research, this book will be essential reading for manufacturers, designers and engineers in the textiles industry, textile and fiber scientists, and academic researchers and postgraduate students working in the area of textile technology.

Key Features

• Provides a thorough overview of current and future focuses of biotechnology in the fiber and textile industry
• Presents fully revised content, with a new focus on biosynthesis and bioprocessing for novel textile fibers, both synthetic and natural
• Enables readers to understand and utilize the benefits of biotechnology for the manufacture and production of textiles

Readership

Textile manufacturers, designers and engineers in the textile industry; textile and fibre scientists; academic researchers and postgraduate students in textile technology; experts in the biology, chemical and environmental engineering industries

Smart textile is a term referring to the textiles that could interact with their environment, receiving input and giving output based on their applications. Among smart textiles, electrically driven smart textiles (E-textiles) are being produced by various methods and materials integrated with textile substances. Graphene is one of these compounds that could be integrated into the polymer or integrated into the textile materials such as fibres. Therefore, other elements could be doped or immobilised on the graphene nanosheets for a wider range of applications, such as catalytic and electrocatalytic systems.  

However, finding the most applicable and efficient method to integrate graphene into the textile fibres and further establishing a method for catalyst immobilisation are challenging and require focused research.  

Therefore, this doctoral thesis focused on the innovative concept of integration of graphene and immobilisation of iron nanoparticles on it. Evidence from the systematic experiments was gathered for the case of dip-coating of polyester textiles with graphene oxide dispersion and enhancing the electrostatic bonding between fibres and graphene oxide nanosheets. In the second step, systematic experiments were gathered for the case of immobilisation of an inorganic catalyst (zerovalent iron) on textile supports. The goal of this thesis is to establish the feasibility of a mild and applicable method for textile material supports, which requires low temperature and mild pH, and further fabrication of heterogeneous catalytic and electrocatalytic systems for wastewater treatment. Polyester was chosen as the textile support material for graphene oxide coating and catalyst immobilisation due to its availability and cost-effectiveness.  

The thesis has four distinct parts related to (a) Pre-surface-charge modification of the polyester for strong electrostatic bonding between polyester and graphene, (b) Design a continuous yarn coating system for mass production of graphene-coated conductive yarns, (c) Immobilisation of Fe0 on graphene-coated polyester textiles and optimising their feasibility in catalytic systems and (d) Design and prove the feasibility of knitting a fully textile-based reactor having two anodic and cathodic sections by using rGO-Fe0 yarns and stainless-steel multifilament yarns, respectively as a concept of electro-Fenton wastewater treatment.  

Diverse analytical and instrumental techniques were used to monitor the surface modification of the polyester textiles and conductivity of the resulting textiles; moreover, the electromechanical and electrothermal properties of the graphene-modified textiles were examined. Further, the efficiency of catalyst immobilisation, physio-chemical properties of the immobilised catalyst, and their catalytical activities in dye removal from the water was studied. Results showed that surface charge modification of polyester fabric with both chitosan and hexadecylpyridinium chloride (HDPC) gives the most homogeneous graphene coating, resulting in high conductivity and very good fastness. Furthermore, results from scanning electron microscope (SEM), Differential scanning calorimetry (DSC), and UV/Visible spectrophotometry prove the success of immobilisation of zerovalent iron on the graphene-modified textiles. 

The novelty of the research presented in this doctoral thesis is primarily attributed to the novelty of a hybrid graphene-catalyst immobilisation-grafting on polyester textile supports for wastewater treatment applications. The final concept of the thesis is to introduce the potential for assembling a fully textile-based reactor for Electro-Fenton wastewater treatments.

Denna studie tas fram i samband med ett mindre modeföretag inom damkonfektion. Företaget har haft återkommande problem med passformen av deras viskosklänning. Syftet med studien är att undersöka viskosmaterialets påverkan efter tvätt på passform så som balans, rörelsevidd, längd och plaggs mått. Viskos är ett av de finaste textilmaterialet för sömnad av klänningar på grund av sin fina glans, snyggt fall och höga absorberande egenskaper. Däremot har viskosmaterial tendensen att förlora styrkan när det är vått, vilket händer att plagget krymper efter tvätt. Studien utförs genom att jämföra tre framtagningsprocessen av en klänning för att få den bästa passformen och önskade plaggmått. För prototyperna A och B används samma mönsterkonstruktion, förutom för prototyp B tvättas viskos tyget i förhand. Medans för prototyp C tvättades med tygprov och krympningen beräknades i cm, mönsterkonstruktioner justerades med att addera resultatet av krympningen. Klänningarna syddes av samma viskostyg, provades på en person i storlek Medium och tog mått på klänningarna både före och efter tvättning. Prototyp C resultatet visades att klänningen har krympt till den bästa passformen och uppfyller önskade plaggmåtten i jämförelse med prototyperna A och B. I Studien visades att plagg som är sytt i viskosmaterial förändas både i passform och mått efter tvätt. Före tvätt av viskosmaterial innan tillskärning kommer inte att garantera att det uppsydda plagget inte krympa eller att plaggen behåller sitt mått efter tvättning. Ändringen i mönsterkonstruktion ger bättre resultat.

Piezoelektriska material används flitigt i olika sensorer då de kan generera en mätbar elektrisk signal vid tryck eller töjning. Arbetet utreder hur ett piezoelektriskt garn innehållandes Polyvinyldiflourid (PVDF) påverkas av faktorer som långvarig mekanisk deformation, fukt och värme. Fokus har legat på det piezoelektriska garnets egenskaper men projektet undersöker också hur integrering i tyg samt applicering i en textil produkt fungerar. Det piezoelektriska garnet har utsatts för ett stort antal tester. I de flesta tester har proverna utvärderats genom cyklisk deformation i en extensometer. Det piezoelektriska garnet har undersökts genom experiment i laboratoriemiljö, praktiska tester i textila applikationer samt vid statistisk analys. Det kan konstateras att yttre faktorer så som fukt och temperatur har inverkan på garnets piezoelektriska effekt. Långvariga tester avslöjar hur garnet uppvisar en längdförändring vid deformation som bidrar till garnets minskade signalstyrka. Garnet kan framgångsrikt integreras i tyg genom sömnad vid rätt inställning för stygnlängd, där högre stygnlängd ger bättre resultat. Samma metod kan användas för att konstruera en piezoelektrisk sensor som appliceras i en träningsstrumpa. Slutsatsen av detta arbete är att parametrar som fukt, krypningsbeteende samt strukturell variation i de individuella PVDF-filamenten har en betydande effekt på det piezoelektriska garnets elektriska signal. Potential i garnets förmåga att fungera som sensor kan ses genom att garnet integrerats med tyg på ett framgångsrikt sätt i en träningsstrumpa för mätning av fotnedsättning. Det kvarstår mycket gällande forskning kring piezoelektriska filament och garn. Vidare forskning i ämnet kommer kunna leda till nya innovativa applikationsmöjligheter som kan komma till nytta inom olika delar av samhället, inte minst inom medicinska användningsområden.

The interest in natural fibres as reinforcement for composite materials has been steadily increasing due to their attractive mechanical properties and the possibility of making more eco-friendly materials. Currently, various alternatives are being introduced for commercial applications, as fibres such as hemp, jute and flax exhibit properties, which make them appropriate for structural composite components. Biocomposites offer reductions in weight and cost and have less reliance on foreign oil resources, making them attractive. Several investigations have revealed that the full utilisation of fibre mechanical properties in the final composites can be exploited, provided an aligned fibre orientation is chosen. In fact, a major challenge for natural fibre reinforced composites is to achieve high mechanical performance at competitive prices. The use of commingled/hybrid yarns is one of the more promising methods for manufacturing structural thermoplastic composites.

Commingled yarns of thermoplastic and reinforcing fibres offer a potential for cost-effective production of composite parts, thanks to reduced applied pressures and impregnation times during processing. Besides economic advantages, there is also direct control over fibre placements and ease of handling of fibres in yarn process. The yarn technologies provide homogenous distribution of reinforcing fibre and matrix. Variation in natural fibre properties has been a major problem facing composite manufacturers, compared to carbon and glass fibres that have well-defined production processes. This issue can be addressed by regenerated cellulose fibres. These fibres can be reproduced easily with high surface evenness and even quality, making it possible to get consistent results, which is not possible with natural fibres. Combination of natural and regenerated cellulose fibre brings together the best of both materials. The end result is a product with superior properties, which could not be obtained by the individual components.

This thesis describes the development of aligned hybrid yarns with low fibre twist, for high performance natural (hemp) and man-made (Lyocell) cellulose fibre-reinforced biocomposites, suitable for use in structural or semi-structural applications. The properties of composites in terms of fibre orientation, off-axis angle and alkali treatment were investigated, focusing on determining void%, water absorption, mechanical and thermo-mechanical properties. The results show that combining hemp and Lyocell in PLA composite leads to the reduction of moisture absorption and can improve the mechanical properties. The mechanical properties of the composites were highly affected by the fibre direction. The alkali treatment on hemp fibre improved the mechanical properties of the composites.

This study reports the recycling of discarded denim textiles by the production of all-cellulose composites (ACCs). Discarded denim fabrics were shredded into fibers and then made into nonwoven fabrics by carding and needle punching. The produced nonwoven fabrics were converted to ACCs by one-step and two-step methods using an ionic liquid (IL), 1-butyl-3-methyl imidazolium acetate ([BMIM][Ac]). In this study, the effect of different ACC manufacturing methods, denim fabrics with different contents (a 100% cotton denim (CO) and a blend material (cotton, poly-ester and elastane (BCO)) and reusing of IL as a recycled cellulose solvent on the mechanical pro-perties of the formed ACCs were investigated. The ACCs were characterized according to their tensile and impact properties, as well as their void content. Microscopic analysis was carried out to study the morphology of a cross-section of the formed composites. The choice of the one-step method with recycled IL, pure IL or with a blend material (BCO) had no influence on the tensile properties. Instead, the result showed that the two-step method, with and without DMSO, will influence the E-modulus but not the tensile strength. Regarding the impact properties of the samples, the only factor likely to influence the impact energy was the one-step method with CO and BCO.

In this work, high-performance fibers such as aramid (Twaron), polyamide (PA6), polyester (PET), and hybrid Twaron/PA6 fibers were transformed into electroactive fibers by coating them with conjugated polymer, poly(3,4-ethylenedioxythiophene) (PEDOT) through vapor phase polymerization (VPP) method. The VPP is considered as an efficient technique for depositing CPs on different substrates regardless of their lower solubility in various solvents. In this paper, PEDOT-coated high-performance fibers were prepared under already optimized reaction conditions, and then a comparison between electrical, thermal, and mechanical properties of different fibers, before and after coating, was made. The obtained coated fibers were characterized through scanning electron microscope (SEM), thermogravimetric analysis (TGA), 2-probe electrical resistance measurement method, and tensile testing. It was revealed that at particular reaction conditions, all high performance textile substrates were successfully converted into electroactive fibers. The voltage-current (V-I) characteristics showed that PEDOT-coated polyester fibers exhibited highest conductivity value among all other substrate fibers. The active PEDOT layers on high performance fibers could behave as an antistatic coating to minimize the risks associated with static charges at work places. Also, the obtained fibers have potential to be used as smart materials for various medical, sports, and military applications.

In this work, high-performance fibers such as aramid (Twaron), polyamide (PA6), polyester (PET), and hybrid Twaron/PA6 fibers were transformed into electroactive fibers by coating them with conjugated polymer, poly(3,4-ethylenedioxythiophene) (PEDOT) through vapor phase polymerization (VPP) method. The VPP is considered as an efficient technique for depositing CPs on different substrates regardless of their lower solubility in various solvents. In this paper, PEDOT-coated high-performance fibers were prepared under already optimized reaction conditions, and then a comparison between electrical, thermal, and mechanical properties of different fibers, before and after coating, was made. The obtained coated fibers were characterized through scanning electron microscope (SEM), thermogravimetric analysis (TGA), 2-probe electrical resistance measurement method, and tensile testing. It was revealed that at particular reaction conditions, all high performance textile substrates were successfully converted into electroactive fibers. The voltage-current (V-I) characteristics showed that PEDOT-coated polyester fibers exhibited highest conductivity value among all other substrate fibers. The active PEDOT layers on high performance fibers could behave as an antistatic coating to minimize the risks associated with static charges at work places. Also, the obtained fibers have potential to be used as smart materials for various medical, sports, and military applications.

This thesis explores the possibilities of printing enzymes using resource-efficient technologies to promote the binding of other proteins and biomaterials on synthetic textiles. This strategy can be used to develop advanced textiles for applications, for example, in antimicrobial, drug delivery and biosensing. Digital inkjet printing was combined with enzyme technology to ensure minimum use of water, chemicals and energy in textile manufacturing processes.  

Inks containing two enzymes, lysozyme and tyrosinase, were formulated by adjusting several rheological and ionic properties. The activity of these enzymes was optimised while being printed through two different industrial grade piezoelectric printheads. The theoretical printability of the prepared inks was calculated. The effect of printhead temperature and number of printing passes on the activity was evaluated. Polyester (polyethylene terephthalate) and polyamide-6,6 were pre-treated through several techniques to understand their effect on enzyme adhesion, binding and activity retention. Tyrosinase was used to bind lysozyme on plasma activated polyamide-6,6 surface. The effects of printing these two enzymes in various sequences, i.e. tyrosinase before lysozyme and vice-versa on binding stability and activity, were studied. Influence of the printing process on enzyme kinetics was evaluated. Ability to store and reuse printed fabrics was also studied.  

Lysozyme and tyrosinase containing inks showed activity retention of 85% and 60%, respectively. Activity of lysozyme containing ink was optimum at 10–15 mPa.s when glycerol was used as a viscosity modifier. However, the optimum viscosity for tyrosinase containing ink was at 6–9 mPa.s, and carboxymethyl cellulose was found to be the most favourable modifier. For both inks, a surfactant amount below the critical micelle concentration was considered to be the most effective for printing. Among the studied fabric pre-treatment methods (alkaline, cutinase and plasma), it was found that the activity and stability of the enzyme were dependent on the nature of the pretreatment processes, which can be beneficial for different application areas, e.g. drug release and bio-sensing. Upon printing both inks on a plasma treated polyamide-6,6, tyrosinase was able to catalyse lysozyme protein to bind it on fabric. A maximum of 68% lytic activity was retained by lysozyme when it was printed after tyrosinase. This fabric showed inhibition of bacterial growth and retained almost half of its initial activity when cold stored for a month. 

Children suffering from autism spectrum disorder are often reported to encounter sleeping disorder several causes such as hypersensitivity as a result of irregular brain and muscle functions. Disturbance in sleep affects not only their health but also daytime activities including the risk of other cognitive and behavioral impairments. Such hindrance in sleep has been demonstrated to treat therapeutically by measures like the application of deep pressure touch and full body vibration which can be beneficially integrated into the sleeping environment such as on the textile-based platform around the bed. With such a vision, this pilot design project aimed to develop a smart textile based sleeping bag incorporated with sensors to detect awakening stage of the child and thereby actuating stimuli for assuaging the child to fall asleep. To serve the purpose, a micro-controllable body movement detection sensor, based on conductive yarns connected to a vibrating motor was prosperously embedded at the interior of the sleeping bag along with weighted slots to exert deep touch and soothing sensation in the form of wearable technology.

Lysozyme was inkjet printed on two different polyester fabrics considering several challenges of printing enzymes on synthetic fabric surfaces. Wettability of both the fabrics were improved by alkaline pre-treatment resulting reduction in water contact angle to 60±2 from 95°±3 and to 80°±2 from 115°±2 for thinner and coarser fabric respectively. Activity of lysozyme in the prepared ink was 9240±34 units/ml and reduced to 5946±23 units/ml as of collected after jetting process (before printing on fabric). The formulated ink was effectively inkjet printed on alkali treated polyester fabric for antimicrobial applications. Retention of higher activity of the printed fabric requires further studies on enzyme-fibre binding mechanisms and understanding protein orientation on fabric surface after printing

Enzymes immobilized on synthetic polyethylene terephthalate (PET) textile surface by resource‐efficient inkjet printing technology can promote developments for various novel applications. Synthetic fabrics often require adequate pretreatments to facilitate such printing process. This work discusses PET–woven fabric pretreatment routes to improve wettability by alkaline, enzymatic, and plasma processes for effective printing of lysozyme using an industrial piezoelectric printhead. Results indicate that all pretreated samples contain a similar amount of enzymes upon printing. Plasma treated fabrics show relatively more hydrophilic surface characteristics, better protein binding stability, and lower retained activity. Alkali and cutinase‐treated samples possess relatively higher activity due to the greater amount of enzyme desorption to substrate solution. Depending on respective enzyme‐binding stability, a combination of a well-pretreated surface and inkjet as preferential placement technology, the approach of this study can be used as a facile enzyme immobilization method for suitable applications, for example, controlled‐release and bio‐sensing.

Inkjet printing of enzymes can facilitate many novel applications where a small amount of materials need to be deposited in a precise and flexible manner. However, maintaining the satisfactory activity of inkjet printed enzyme is a challenging task due to the requirements of ink rheology and printhead parameters. Thus to find optimum inkjetting conditions we studied the effects of several ink formulation and jetting parameters on lysozyme activity using a piezoelectric printhead. Within linear activity range of protein concentrations ink containing 50 µg/mL lysozyme showed a satisfactory activity retention of 85%. An acceptable activity of jetted ink was found at pH 6.2 and ionic strength of 0.06 molar. Glycerol was found to be an effective viscosity modifier (10–15 mPa.s), humectant and protein structure stabilizer for the prepared ink. A non-ionic surfactant when used just below critical micelle concentration was found to be favourable for the jetted inks. An increase in activity retention was observed for inks jetted after 24 hours of room temperature incubation. However, no additional activity was seen for inkjetting above the room temperature. Findings of this study would be useful for formulating other protein-based inks and setting their inkjet printing parameters without highly compromising the functionality.

Immobilization of enzymes on textiles can impart a range of advanced applications e.g. anti-microbial, controlled release, drug delivery and bio-sensing (Wehrschütz-Sigl et al., 2010). Such applications enable minimal consumption, recovery, and reusability of these valuable bio-materials compared to their conventional textile applications in surface cleaning and finishing (Araujo et al., 2008). Methods used for immobilization can play important roles to ensure precise, flexible and contamination free application. Compared to many of the conventional methods of textile immobilization such as coating and screen-printing, digital inkjet technology offers many benefits for such advanced applications (Kan and Yuen, 2012). Among various inkjet technologies, drop-on-demand piezoelectric printing is a promising resource-efficient technology for enzyme immobilization. 

The enzymes should retain high activity after the immobilization process. Various factors involved during inkjet printing (Saunders and Derby, 2014) and fabric characteristics (Mohamed et al., 2008) can influence this enzymatic activity. Factors concerning the inkjet procedure include rheology and ionic nature of ink along with the shear force and waveform generated inside a piezoelectric printhead (Magdassi, 2010). Factors dependent upon fabric characteristics include surface structure, pore size distribution, and binding mechanism (Nierstrasz and Warmoeskerken, 2003). In this work, we have studied the effects of inkjet procedures on enzymatic activity. Lysozyme being a stable and well-studied enzyme was chosen for our experiments. A Xennia Carnelian printer with a Dimatix QS10 industrial printhead was used for inkjetting. Lytic activity of lysozyme was studied by a UV-Vis spectrophotometer against decrease of Micrococcus lysodeikticus cell concentration at 450 nm. Results showed ca. 10-15% activity reduction of the jetted lysozyme ink. As all the ink and printer parameters were optimized, the probable reason for such reduction could be the effect of shear forces inside the printhead on three-dimensional conformation of lysozyme. In conclusion, our formulated lysozyme ink showed potential for printing textiles with probable activity reduction that require further investigation. 

Enzymes can be immobilized on textiles to impart anti-microbial properties in a more environment-friendly manner compared to conventional biocide-based solutions. Such application requires ensuring precise, flexible and contamination-free immobilization methods that can be offered by digital printing compared to coating or screen-printing techniques. Drop-on-demand inkjet printing is a resource-efficient technology that can ensure these requirements. The use of polyester and polyamide-based fabrics is rising for applications ranging from apparel and home furnishing to hygiene and medical textiles. These fibers offer superior chemical, physical, and mechanical properties due to their inert nature but challenge the printing process due to hydrophobicity and lack of functional groups. Lysozyme and tyrosinase are two enzymes showing great potential for grafting on synthetic fabrics paving the way to use them for inkjet printing as well.

Challenges for inkjet printing of enzymes on synthetic fabric surfaces come in multiple forms i.e. ink recipe formation, printer mechanics and fabric surface characteristics. The ink must maintain a suitable viscosity and surface tension for effective drop ejection and a feasible ionic nature for enzyme activity. Then, the enzyme must be able to sustain the temperature and shear stress generated inside an inkjet printhead. Finally, influential fabric characteristics include surface structure, pore size distribution, evaporation rate and binding mechanism. By considering these parameters, lysozyme and tyrosinase were successfully printed on variously modified synthetic fabrics using a combination of sustainable technologies.

Tyrosinase enzyme was digitally printed on plasma pretreated polyamide-6,6 fabric using several sustainable technologies. Ink containing carboxymethyl cellulose was found to be the most suitable viscosity modifier for this enzyme. Before and after being deposited on the fabric surface, the printed inks retained enzyme activity of 69% and 60%, respectively, compared to activity prior printing process. A good number of the printed enzyme was found to be strongly adsorbed on the fabric surface even after several rinsing cycles due to surface activation by plasma treatment. Rinsed out fabrics retained a maximum activity of 34% resulting from the well-adsorbed enzymes. The activity of tyrosinase on printed fabrics was more stable than ink solution for at least 60 days. Effects of pH, temperature and enzyme kinetics on ink solution and printed fabrics were assessed. Tyrosinase printed synthetic fabrics can be utilized for a range of applications from biosensing and wastewater treatment to cultural heritage works.

 Inse mitt värde och behåll mig en stund till är ett utforskande projekt i hållbar textildesign. Huvudfokuset i projektet är att utforska vilka möjliga designlösningar som kan ge produkter egenskapen av föränderlighet och på så vis möjliggöra en förlängning av deras livscykler. Detta undersöks utifrån ett eget formulerat förhållningssätt till hållbar design, genom praktiska experimentella undersökningar av olika material och föränderliga mönsterbilder. Detta kombinerat med att ge konsumenten en aktiv roll i förändring av en produkts utseende och funktion. Projektet resulterar i tre produktprototyper som på olika sätt gestaltar föränderlighet och det formulerade förhållningssättet. 1. Mossa, en tröja gjord av rundstickat, jacquard trikåtyg med materialkombinationen Sally Fox bomull och oblekt bomull. Textilen är ett följsamt mjukt tyg med en mönsterbild som ändrar nyans för varje gång konsumenten tvättar den. 2. Kotte, ett påslakan och örngott gjord av en fem-skaftad satängväv i jacquard- teknik. En textil där mönsterbild och färg inverteras på den aviga sidan. Sängklädernas estetiska uttryck kan förnyas av konsumenten själv genom växtfärgning. 3. Bark, en ullfilt gjord av flatstickad dubbelrelief stickning med olika maskstorlekar i jacquardteknik. Filten kan transformeras av konsumenten själv, genom tvättning, och då få en ny funktion som matta. Den går då från en mjuk, tvådimensionell och följsam textil till en kompakt, tredimensionell tålig textil.

In electronic textiles, we apply production techniques from both textiles and electronic engineering to bridge the gap between these two very different materials. While it is obvious to apply electronic engineering to textiles to ensure the working of the electronic components, the application of textile production techniques to electronics is still challenging. Yet it is in the appropriation of textile manufacturing that there is a huge potential for innovation. This potential does not only cover the means of production, but also the way we interact with digital interfaces as well as the overall aesthetic of those interfaces.

This report documents the application of textile production techniques for sensing and actuation in e-textile structures and artifacts. It shows how weaving and knitting on industrial machines can be used to design and build electronic elements in a textile shape, such as pressure sensors, speaker coils and shape change structures. The report also documents the application of those techniques in two different prototypes, the first being a sensor glove that was used for gesture recognition, and the second being woven textile muscle that was developed as the basis for a soft textile robot.

Textiles are pervasive in our life, covering human body and objects, as well as serving in industrial applications. In its everyday use of individuals, smart textile becomes a promising medium for monitoring, information retrieval, and interaction. While there are many applications in sport, health care, and industry, the state-of-the-art smart textile is still found only in niche markets. To gain mass-market capabilities, we see the necessity of generalizing and modularizing smart textile production and application development, which on the one end lowers the production cost and on the other end enables easy deployment. In this chapter, we demonstrate our initial effort in modularization. By devising types of universal sensing fabrics for conductive and non-conductive patches, smart textile construction from basic, reusable components can be made. Using the fabric blocks, we present four types of sensing modalities, including resistive pressure, capacitive, bioimpedance, and biopotential. In addition, we present a multi-channel textile–electronics interface and various applications built on the top of the basic building blocks by ‘cut and sew’ principle.

An industrial dyeing process in supercritical carbon dioxide has been modelled with computational fluid dynamics using Ansys Fluent software. In order to investigate the distribution of the dye carrier fluid, the flow resistance of the fabric has been accurately characterised. For this purpose, in the first part of the work a plain-woven fabric geometry was created in the open software Tex-Gen and modelled in Ansys Fluent to predict the permeation of fluid through the pores of the fabric material and to estimate the relationship between local fluid velocity and pressure drop. The second part of the study focused on evaluating the influence of beam structure, inlet flow rate, fabric height on the fluid flow through the fabric, which must be uniform to achieve a homogeneous level of dyeing. From the simulations the main obstacle to achieving a uniform flow velocity in the fabric is the pressure rise that occurs in the beam and creates a slight difference in permeation velocity between the two axial ends of the fabric; other disturbances, such as the effect of the perforated structure of the beam, are usually minor. Due to the low viscosity of supercritical carbon dioxide, inertial losses predominate over viscous losses in the porous medium. This means that approaches based only on the permeability of the fabric and the application of Darcy's law are inadequate to correctly predict the response of a dyeing unit when using carbon dioxide.

Arbetet syftar till att skapa en prototyp av en textil trycksensor som kan känna av och skilja på olika typer av belastning. En lämplig metod för att på ett vetenskapligt sätt testa sagda prototyp har också utvecklats. Prototypen har tillverkats för hand på en datoriserad vävstol och de ingående materialen är piezoelektrisk poly(vinyldifluorid), PVDF, tvinnad tillsammans med ett konduktivt garn, Shieldex®, samt polyester. När PVDF-fiber utsätts för töjning genererar de en spänning, vars storlek står i relation till töjningen. Den vävda konstruktion som valdes till prototypen är en distansvara där väftinläggen lagts in i 7 olika lager för att skapa volym. Därmed möjliggörs en töjning av PVDF-fibern som relaterar till trycket strukturen utsätts för.

För att utvärdera strukturen skapades tre likadana trycksensorer innehållandes fyra PVDF-fiber som lagts in med ett mellanrum på ca 1,5 cm. Dessa prototyper har sedan fästs på en egentillverkad ramp och PVDF- samt Shieldex®-garnet har kopplats in till ett oscilloskop. Därefter har vikter rullats över prototypen för att generera spänning, vilken har kunnat uppmätas med oscilloskopet. De uppmätta resultaten har analyserats och utvärderats med hjälp av Excel.

Testerna visade tydligt att spänningen som uppmättes stod i relation till vikternas storlek; högre vikter gav en mätbart större spänning. Det finns dock stor varians bland resultaten och utvärdering av samtliga prover visar på stora standardavvikelser hos samtliga fiber. Detta innebär att även om det är tydligt att ökad vikt medför ökad signal så kan det finnas svårigheter i att avgöra storleken på vikten utifrån den uppmätta spänningen.

In this collection I have explored the paradox of perfection. The collection is an epic tribute to my prior self and discovers how the unperfect can be transformed to something, perceived, perfect. I flirt with my past obsessions in finding mathematically measured legs, exact tailored arms and perfectly fitted stockings. In a fun, poetic and melancholy way I invite the viewer on a highly visual voyage to my childhood where the obsession of finding costume perfection "Vemoden" the act of control becomes visual through statuesque frozen looks, where the previous unperfect becomes perfection.

The relationship between technology and the expression of form have always been interconnected in the architectural design process; associating the art of envisioning spaces with the craft of materializing them. Recently in terms of surface fabrication, computational tools of representation and material fabrication opened for architectural design new possibilities to explore novel spatial expressions. Surface design processes in architecture start to borrow from the logic of representation of different non-hierarchical structures, e.g., biological systems or textile construction techniques. Relating to that, the present fascination of textiles in architectural design relies on this specific way of building surface design as non-hierarchical form, and by that, allowing the designer to play with the depth of the surface design at micro and macro levels. Exploring different relations between digital and physical through textiles expressions, this research reassess static principles of form–marking the turn from static to relational principles. Thus, the intention is to describe how the character of the textiles and computation as design material redefines the notion of space trough surface aesthetics merging the digital to the physical, and how spatiality can be questioned through textile and interaction aesthetics. Using practice-based research methodology, this research opens and explores this design space by relating theory and practice; it questions and reframes fundamental concepts of expression and scale in architecture by proposing methods for surface design, and a specific language to describe textile architectural aesthetics.

As a way of opening a space where methods from the fields of fashion design, textile design and interaction design overlap, the project Repetition intersects different methodologies through practice-based research in design. Experiments were conducted to explore ways of creating relationships between body and space by means of translating information as pattern design between garments and interactive knitted walls. By arranging a startup performance, we reflected on the expressional variables that influence the expression of the pattern translations; variables concerning the garments, the walls, the print and the movements were illustrated by the expressions found. The result formulates specific descriptions regarding accuracy and distribution of pattern translation, illustrating basic concepts of pattern formations identified in visual changes appearing in the garment. By communicating our understanding of basic expressions, Repetition aims to formulate a new framework for collaborative work as a method for further design.

Hospital-acquired infections have become a major challenge which threaten the hospitalized patients’ safety. The presence of nosocomial pathogens is generally reported in connection with solid surfaces near patient environments. These surfaces become significant sources of transmission and lead most often to the contamination and cross-contamination of nosocomial pathogens to the patients and staff. This paper investigates strategies to apply beneficial bacteria on viscose-based nonwoven wipes and the viability of these beneficial bacteria on the wipes along with characterization of the physical properties of the wipes. Major findings include that it is possible to produce dry wipes which contain an adequate number of beneficial bacteria or spores. After these wipes are wetted, they can release a certain number of bacteria from the wetted wipes. These released beneficial bacteria can inhibit pathogens by growing and colonizing on the wiped surfaces.

Adopting circular economy approaches is becoming an increasingly important part of policy makers’ agendas in the fight against climate change. These approaches include reducing material inputs, using more environmentally friendly and reusable materials when producing goods, ensuring materials are properly recycled, and minimizing waste and pollution. They have become even more important in the wake of the COVID-19 pandemic, with personal protective equipment (PPE) becoming an inseparable part of daily life. Manufacturers across the globe had to increase PPE production, which inevitably created a surge in plastic waste because polypropylene is still the main material used to manufacture PPE for health-care workers. A recent research study estimates that, since the outbreak, the amount of plastic waste generated globally is 1.6 million tons per day.Furthermore, an estimated 3.4 billion single-use face masks and shields are being discarded every day. This unpredicted increase in plastic waste is happening at a time when countries are reluctant to recycle products because of the lack of complementary decontamination steps and coordination in waste management.Some manufacturers took this opportunity of increased PPE production to adopt circular economy approaches that can be replicated by others. Decentralized production and material sourcing became more important as supply chains were severely disrupted by the pandemic. This has accelerated the ongoing changes in conventional production methods, with businesses embracing a cradle-to-cradle manufacturing model—that is, rethinking the design of their products from the starting point at the sourcing stage through to the end of the product’s life.

This is not without its challenges. For example, when replacing plastics with alternative materials, manufacturers need to ensure that these materials meet quality standards set by standards institutions and enforced by governments.However, PPE manufacturers cannot shoulder the responsibility of the global plastic waste challenge alone. This publication calls on a broad range of stakeholders along the PPE value chain to work together to shift toward a more sustainable and circular PPE ecosystem.This report takes stock of approaches that PPE manufacturers are taking to make their production more sustainable and achieve a true circular economy, while responding to COVID-19 PPE shortages. It does not provide a life-cycle assessment of each PPE product, which is needed to evaluate the environmental effects associated with each product against the benefits created. The approaches highlighted in this report can be grouped into four main categories:

•Circular inputs: The use of renewable, bio-based, or completely recyclable materials as input.

•Resource recovery: Ensuring that useful resources and energy are recovered from disposed products by collecting and reprocessing products at the end of their life.

•Product use extension: Prolonging the lifespan of PPE products by choosing a design that allows the product to be repaired or by choosing durable materials as inputs for the main PPE parts.

•Product as service: The product-as-service model allows the consumer to use a product that is retained by the producer to increase resource productivity (for example, leasing PPE). This model allows PPE manufacturers to move from selling products to selling services.

Recently, electrically driven conducting polymer (CP) coated yarns have shown great promise to develop soft wearable applications because of their electrical and mechanical behaviour. However, designing a suitable yarn actuator for textile-based wearables with high strain is challenging. One reason for the low strain is the voltage drop along the yarn, which results in only a part of the yarn being active. To understand the voltage drop mechanism and overcome this issue intrinsically conductive yarns were used to create a highly conductive path along the full length of the yarn actuator. Ag plated knit-de-knit (Ag-KDK) structured polyamide yarns were used as the intrinsically conductive core material of the CP yarn actuators and compared with CP yarn actuators made of a non-conductive core knit-de-knit (KDK) yarn. The CP yarn actuators were fabricated by coating the core yarns with poly(3,4-ethylene dioxythiophene): poly(styrene sulfonic acid) followed by electrochemical polymerization of polypyrrole. Furthermore, to elucidate the effect of the capillarity of the electrolyte through the yarn actuator, two different approaches to electrochemical actuation were applied. All actuating performance of the materials were investigated and quantified in terms of both isotonic displacement and isometric developed forces. The resultant electroactive yarn exhibits high strain (0.64 %) in NaDBS electrolytes as compared to previous CP yarn actuator. The actuation and the electroactivity of the yarn were retained up to 100 cycles. The new highly conductive yarns will shed light on the development of next-generation textile-based exoskeleton suits, assistive devices, wearables, and haptics garments.

The following have been rectified in response to previous evaluation by examiner Olof Bruninge. -We have solely chosen qualitative methods in data collection and analysis by making use of data gathered from focus group workshop. The findings have been coded and analysed descriptively. -We have reformulated research questions and replaced the hypothesis with open questions. Allowing us to explore the participants’ behaviour rather than testing hypothesis. -All quantitative measures have been replaced with qualitative analysis and descriptions. -We have provided tables with results from focus group findings to increase transparency in our data

The number of 3D textile applications in medicine is rapidly increasing as new technology and procedures are introduced in health care.  A first estimate of current medical applications of both general and 3D textiles is presented based on the medical devices classification system established by the US Food and Drug Administration. The textile specifics for these applications are covered from a textile technique perspective where the different 3D weaving as well as knitting, braiding and non-woven techniques are described and how their properties they can contribute in medical applications. In addition, emerging opportunities based on smart textiles as part of textile systems are described on a general level. The strong application areas of 3D medical textiles, i.e. wound management, vascular grafting and scaffolding for tissue engineering are covered in detail both from the medical and textiles perspective. Finally, some future lines of development are suggested and a short discussion on how new 3D textiles applications can be developed in close cooperation between the textile industry and the health care sector is presented.

Electrical stimulation can be used for the treatment of various nerve and muscle injuries as well as acute and chronic pain conditions. An electrical pulse is applied to a muscle or nerve to activate excitable tissue using internal or external electrodes with the aim of building muscle strength, artificially creating or supporting limb movement or reducing pain. Textile electrodes offer several advantages over conventionally used disposable surface electrodes: they are flexible and re-usable and they do not require hydrogels, thereby avoiding skin irritation and allergic reactions and enhancing user comfort. This article presents a literature review that assesses the state of research on textile electrode constructions. Based on the review, production approaches and designs are compared, methods for evaluating stimulation discomfort and pain are proposed and issues related to user compliance are discussed. The article concludes with suggestions for future work focused on investigating the impacts of textile-based electrode parameters on comfort, convenience and ease of use.

Denna avhandling syftar till att karakterisera tredimensionella (3D) tryckta polymerer på textilamaterial av polyester (PET) via fused deposition modeling (FDM) som använder både icke-ledande ochledande polymerer, optimerar deras mekaniska och elektriska egenskaper genom statistisk modelleringsamt förbättrar dem med för- och efterbehandlingar och utvecklingen av polymerblandningar. Dettaforskningsarbete stöder utvecklingen av tekniska textilier genom 3D-utskrift som kan ha funktioner. FDMprocessenvaldes i denna avhandling för sin stora potential i flexibilitet avseende process, resurseffektivitet,kostnadseffektiv skräddarsydd produktion och ekologi jämfört med befintliga konventionellatextilbearbetningsprocesser, till exempel digital- och skärmtryck. Den huvudsakliga utmaningen med dennateknik är att garantera optimerade elektriska och mekaniska egenskaper (böjning, flexibilitet, drag, nötning,etc.) för 3D-tryckta polymerer på textilier för material att användas i textilindustrin. Därför är utvecklingenav nya 3D-tryckta polymerer på PET-material med förbättrade egenskaper nödvändig.Först och främst köptes icke-ledande polylaktid (PLA) och PLA fylld med 2,5 viktprocent kimröktillverkades genom smältextrudering och 3D-trycktes på PET-tyger, för att karakterisera deras mekaniskaegenskaper inklusive vidhäftning, draghållfasthet, deformation, tvättbarhet och nötningstålighet. Därefterbestämdes förhållandet mellan textilens strukturella och termiska egenskaper och plattformstemperatur ochdessa egenskaper bestämdes genom statistisk modellering. Därefter testades olika textila förbehandlingarså som atmosfärisk plasma, ympning av akrylsyra och applicering av lim för att förbättravidhäftningsegenskaperna hos 3D-tryckt PLA på PET-tyger. Slutligen utvecklades och tillverkades nyabiofasiska blandningar med lågdensitetspolyeten (LDPE) / propylenbaserad elastomer (PBE) fyllda medflerväggade kolnanorör (CNT) och högstrukturerad kimrök (KB) för att förbättra flexibiliteten, spänningoch belastning vid bristning och de elektriska egenskaperna hos 3D-tryckt PLA på PET-tyg. Morfologin,samt de termiska och reologiska egenskaperna hos varje blandning analyserades också för att förståmaterialegenskaper och förbättrade mekaniska och elektriska egenskaper.Resultaten visade att textilstrukturen så som den är definierad av dess väfttäthet och konstruktion ochväft- och varpgarnskompositioner har en signifikant inverkan på vidhäftning, deformation, nötning ochdragegenskaper hos 3D-tryckt PLA på PET-tyger. Kompromisser måste göras eftersom porösa och grovatextilier med låga termiska egenskaper visade bättre tvättförmåga, vidhäftning och dragegenskaper ochsämre deformation och nötningsbeständighet. Statistiska modeller mellan textilegenskaperna, 3D-trycktPLA på PET-material och egenskaperna har framgångsrikt utvecklats och använts för optimering.Applicering av lim på behandlad PET med ympad akrylsyra förbättrade signifikant vidhäftningsresistensenoch LDPE/PBE-blandningar fyllda med CNT och KB som har ko-kontinuerliga LDPE- och PBE-faser samtCNT och KB selektivt belägna vid gränssnittet och i LDPE-fasen gav förbättrad deformation, drag- ochelektriska egenskaper.

3D printing utilized as a direct deposition of conductive polymeric materials onto textilesreveals to be an attractive technique in the development of functional textiles. However, the conductivefillers—filled thermoplastic polymers commonly used in the development of functional textiles through3D printing technology and most specifically through Fused DepositionModeling (FDM) process—arenot appropriate for textile applications as they are excessively brittle and fragile at room temperature.Indeed, a large amount of fillers is incorporated into the polymers to attain the percolation thresholdincreasing their viscosity and stiffness. For this reason, this study focuses on enhancing the flexibility,stress and strain at rupture and electrical conductivity of 3D-printed conductive polymer onto textiles bydeveloping various immiscible polymer blends. A phase is composed of a conductive polymer composite(CPC)made of a carbon nanotubes (CNT) and highly structured carbon black (KB)- filled low-densitypolyethylene (LDPE) and another one of propylene-based elastomer (PBE) blends. Two requirements areessential to create flexible and highly conductive monofilaments for 3D-printed polymers onto textilematerials applications. First, the co-continuity of both the thermoplastic and the elastomer phases and thelocation of the conductive fillers in the thermoplastic phase or at the interface of the two immisciblepolymers are necessary to preserve the flexibility of the elastomer while decreasing the global amountof charges in the blends. In the present work based on theoretical models, when using a two-stepmelt process, the KB and CNT particles are found to be both preferentially located at the LDPE/PBEinterface. Moreover, in the case of the two-step extrusion, SEM characterization showed that the KBparticles were located in the LDPE while the CNT were mainly at the LDPE/PBE interface and TEManalysis demonstrated that KB and CNT nanoparticles were in LDPE and at the interface. For one-stepextrusion, it was found that both KB and CNT are in the PBE and LDPE phases. These selectivelocations play a key role in extending the co-continuity of the LDPE and PBE phases over a much largercomposition range. Therefore, the melt flow index and the electrical conductivity of monofilament,the deformation under compression, the strain and stress and the electrical conductivity of the 3D-printedconducting polymer composite onto textiles were significantly improved with KB and CNT-filledLDPE/PBE blends compared to KB and CNT-filled LDPE separately. The two-step extrusion processed60%(LDPE16.7% KB + 4.2% CNT)/40 PBE blends presented the best properties and almost similar to theones of the textile materials and henceforth, could be a better material for functional textile developmentthrough 3D printing onto textiles.

Although direct deposition of polymeric materials onto textiles through 3D printing is a great technique used more and more to develop smart textiles, one of the main challenges is to demonstrate equal or better mechanical resistance, durability and comfort than those of the textile substrates before deposition process. This article focuses on studying the impact of the textile properties and printing platform temperature on the tensile and deformations of non-conductive and conductive poly lactic acid (PLA) filaments deposited onto polyethylene terephthalate (PET) textiles through 3D printing process and optimizing them using theoretical and statistical models. The results demonstrate that the deposition process affects the tensile properties of the printed textile in comparison with the ones of the textiles. The stress and strain at rupture of the first 3D printed PLA layer deposited onto PET textile material reveal to be a combination of those of the printed layer and the PET fabric due to the lower flexibility and diffusion of the polymeric printed track through the textile fabric leading to a weak adhesion at the polymer/textile interface. Besides, printing platform temperature and textile properties influence the tensile and deformation properties of the 3D printed PLA on PET textile significantly. Both, the washing process and the incorporation of conductive fillers into the PLA do not affect the tensile properties of the extruded polymeric materials. The elastic, total and permanent deformations of the 3D-printed PLA on PET fabrics are lower than the ones of the fabric before polymer deposition which demonstrates a better dimensional stability, higher stiffness and lower flexibility of these materials.

Wear resistance of conductive Poly Lactic Acid monofilament 3D printed onto textiles, through Fused Deposition Modeling (FDM) process and their electrical conductivity after abrasion are important to consider in the development of smart textiles with preserved mechanical and electrical properties. The study aims at investigating the weight loss after abrasion and end point of such materials, understanding the influence of the textile properties and 3D printing process parameters and studying the impact of the abrasion process on the electrical conductivity property of the 3D printed conductive polymers onto textiles. The effects of the 3D printing process and the printing parameters on the structural properties of textiles, such as the thickness of the conductive Poly Lactic Acid (PLA) 3D printed onto polyethylene terephthalate (PET) textile and the average pore sizes of its surface are also investigated. Findings demonstrate that the textile properties, such as the pattern and the process settings, for instance, the printing bed temperature, impact significantly the abrasion resistance of 3D printed conductive Poly Lactic Acid (PLA) onto PET woven textiles. Due to the higher capacity of the surface structure and stronger fiber-to-fiber cohesion, the 3D printed conductive polymer deposited onto textiles through Fused Deposition Modeling process have a higher abrasion resistance and lower weight loss after abrasion compared to the original fabrics. After printing the mean pore size, localized at the surface of the 3D-printed PLA onto PET textiles, is five to eight times smaller than the one of the pores localized at the surface of the PET fabrics prior to 3D printing. Finally, the abrasion process did considerably impact the electrical conductivity of 3D printed conductive PLA onto PET fabric.

Purpose

This paper aims to evaluate and simulate the impact of the build platform temperature of the three-dimensional (3D) printer, the structure and heat transfer of textiles on the adhesion and durability after washing properties of 3D printed polymer onto textile materials using thin layers of conductive and non-conductive extruded poly lactic acid monofilaments (PLA) deposited on polyethylene terephthalate (PET) woven fabrics through fused deposition modeling (FDM) process.

Design/methodology/approach

Prior to FDM process, thermal conductivity, surface roughness and mean pore size of PET woven fabrics were assessed using the “hot disk,” the profilometer and the capillary flow porometry methods, respectively. After the FDM process, the adhesion and durability after the washing process properties of the materials were determined and optimized based on reliable statistical models connecting those properties to the textile substrate properties such as surface roughness, mean pore size and thermal conductivity.

Findings

The main findings point out that higher roughness coefficient and mean pore size and lower thermal conductivity of polyester woven textile materials improve the adhesion properties and the build platform presents a quadratic effect. Additionally, the adhesion strength decreases by half after the washing process and rougher and more porous textile structures demonstrate better durability. These results are explained by the surface topography of textile materials that define the anchorage areas between the printed layer and the textiles.

Originality/value

This study is for great importance in the development of smart textiles using FDM process as it presents unique and reliable models used to optimize adhesion resistance of 3D printed PLA primary layer onto PET textiles.

FDM technology used for printing functionalized layers on textiles brought new challenges such as the understanding and the improvement of the adhesion performance of the thermoplastic filaments on synthetic textile materials. In addition to the impact of printing parameters, the correlation between the heat transfer and structure of the textile material and the adhesion performance after varying printer platform temperature was an important parameter considered in this paper. A factorial design, using material density, direction, and structure and platform temperature as factors, was followed. 3D-printed materials made of PLA filaments deposited on polyester woven and knit materials were manufactured on a dual-head printer and their adhesion was measured according to DIN EN ISO 13937-2 and ISO 11339 and the heat transfer of the fabrics according to ASTM D4966-98, ISO 6330 and ISO 22007-2. The findings showed that the heat transfer and structure of textile materials affect the adhesion properties of the 3D-printed material.

Adhesion of conductive poly-lactic acid filament (PLA) 3D printed onto polyethylene terephthalate (PET) fabrics is a one of the fundamental properties to guarantee their use in smart textiles field. The conductive PLA layer is made of carbon black (CB) incorporated into PLA polymer prior to extrusion process. It is commonly known that due to the low surface tensions of polymeric materials, 3D printed conductive PLA onto PET textiles possess poor adhesion. Therefore, an improvement of this property, even already approached by some researchers (1–6), is still highly required. In this research work, a pre and post-treatments were applied to significantly improve the adhesion strength at the interface polymeric layer/textile compared to former techniques used in other researches such as plasma treatment; coating of glue stick, washing and ironing processes. The pre-treatment consists in grafting acetic acid by UV curing onto both PET fabric and PLA filament through digital printing and deep coating respectively and then applying a solution pressure sensitive adhesive (PSA) on the fabric via digital printing. After 3D printing process on textiles, heat and pressure were applied on the materials using a heat press to chemically bond the PLA layer to the PET fabric. The findings are very promising as they demonstrate the possibility of significantly improving the adhesion of thermoplastic polymer 3D printed on textiles for smart textiles applications. Compared to other alternative solutions, these findings can potentially be implemented, in the future, by using 3D printing technology for pre-treatment and printing processes followed by thermo-compression technique for complete chemical bonding.

The present work is focused on the synthesis of bio-based thermoset polymers and their thermo–oxidative ageing and biodegradability. Toward this aim, bio-based thermoset resins with different chemical architectures were synthesized from lactic acid by direct condensation with ethylene glycol, glycerol and pentaerythritol. The resulting branched molecules with chain lengths (n) of three were then end-functionalized with methacrylic anhydride. The chemical structures of the synthesized lactic acid derivatives were confirmed by proton nuclear magnetic resonance spectroscopy (¹H-NMR) and Fourier transform infrared spectroscopy (FT–IR) before curing. To evaluate the effects of structure on their properties, the samples were investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and the tensile testing. The samples went through thermo-oxidative ageing and biodegradation; and their effects were investigated. FT-IR and ¹H-NMR results showed that three different bio-based resins were synthesized using polycondensation and end-functionalization. Lactic acid derivatives showed great potential to be used as matrixes in polymer composites. The glass transition temperature of the cured resins ranged between 44 and 52 °C. Pentaerythritol/lactic acid cured resin had the highest tensile modulus and it was the most thermally stable among all three resins. Degradative processes during ageing of the samples lead to the changes in chemical structures and the variations in Young’s modulus. Microscopic images showed the macro-scale surface degradation on a soil burial test.