För att nå de Globala målen 2030 kommer vi som samhälle att behöva minska vårt globala ekologiska fotavtryck avsevärt. Textilbranschen står idag för en betydande del av detta ekologiska fotavtryck både genom markanvändning, klimatpåverkande utsläpp, förorening av mark och vatten med mera. Detta har lett till att man inom textilbranschen idag efterfrågar allt mera hållbara lösningar. Det finns ett antal sorters garn som bidrar med lägre miljöpåverkan på olika sätt, dock förekommer dessa idag mindre frekvent på marknaden. Dessa material skulle kunna vara en del av lösningen på textilindustrins stora miljöpåverkan idag. Ett av dessa material som vi valt att titta närmare på var pappersgarn, som vid framställning förbrukar betydligt mindre resurser som vatten, tillsatskemikalier och energi (Fakirov 2015). Pappersgarnets utveckling har dock än så länge begränsats av dess styvhet och dåliga stickbarhet. Detta projektetet har syftat till att försöka minska pappersgarnets styvhet och öka dess stickbarhet genom att tvinna det med olika antal garnsnodd av viskosgarn. Vi tvinnade ett entrådigt 17 tex hampaviskosgarn på 100, 300 och 500 garnsnodd/meter med kärnspunnen metoden. Sedan behandlades garnet med fettsyra för att motverka sprödheten och förbereda för stickning. Garnet stickades på en rundstickmaskin med bindningen slätstickning. Tester som gjordes på garn var dragprovning och friktion. På trikån utfördes också dragprovning(bristning) men även styvhetsprovning samt nötningsprovning. Trikå av blandgarn visades sig tillföra mjukare känsla på tyget jämfört med endast papper. Vid dragprovning av trikå framkom det att större andel av viskos tillför mer styrka i och med att det behövdes högre tryck samt tid för att uppnå brott på trikån. Tvinning med olika antal garnsnodd av viskosgarn har visat sig medföra små skillnader gällande stickbarhet då det tidvis uppstod hål på de fyra olika tyger som stickades under stickningsprocessen. Garner av 300- och 500 garnsnodd/meter hade dock flest svaga punkter (brott på pappersgarnet) utan att uppvisa synbara hål på tyget. Skillnader i styvhet av trikån var kännbara mellan alla tygen, dock gick det inte att få användbara resultat från styvhetsprovaren då denna testmetod var olämplig för den valda trikåbindningen eftersom tyget rullade sig. / To achieve the Global Goals 2030, we as a society will need to significantly reduce our global ecological footprint. The textile industry of today accounts for a significant part of this ecological footprint both through use of land, climate-affecting emissions, soil- and water pollution and more. This has led to an increasing demand for more sustainable solutions in the textile industry. There are a number of types of yarn that have a lower environmental impact. Many of them however have quite a lower market share today. One of these materials that we chose to take a closer look at was paper yarn, which in it’s production consumes significantly less resources than other usual yarns on the market (Fakirov 2015). However, the development of use of paper yarn has so far been limited by its rigidity and poor knitability. This project has aimed to try to reduce the stiffness of the paper yarn and increase its knitability. This was done by twisting different numbers of twist/meter of viscose yarn, around the paper yarn. We twisted a single-threaded 17 tex hemp viscose yarn around the paper yarn at 100, 300 and 500 twist/meter with the core-spun method. Then the yarn was treated with fatty acid to counteract the brittleness and prepare it for knitting. The yarn was knitted on a circular knitting machine with a single jersey stitch. Tests done on yarn were tensile testing and friction testing. The tricot also was subjected to tensile testing (rupture), stiffness testing and abrasion testing. Viscose mixed yarn knitwear was found to have a softer feeling of the fabric compared to just knitted paper yarn. During tensile testing of tricot, it was found that a larger proportion of viscose adds more strength as higher pressure was needed as well as time to achieve a stretch in the tricot. Twisting with different twists of viscose yarn has been shown to cause small differences in knitability as there were occasional holes in the paper yarn knit during the knitting process. Yarns of 300 and 500 twist/meter, however, had the most weak points without showing visible holes on the fabric. Differences in the stiffness of the tricot were noticeable between all the fabrics, however, it was not possible to obtain useful results from the stiffness tester as this test method was probably unsuitable for the selected tricot binding because the fabric rolled.

As a preliminary starting point for the present study, physical and mechanical properties of polypropylene nanocomposites (PPNCs) for samples received from Queen's University Belfast have been evaluated. Subsequently, polymer/clay nanocomposite material has been produced at Bradford. Mixing and processing routes have been explored, and mechanical properties for the different compounded samples have been studied. Clay intercalation structure has received particular attention to support the ultimate objective of optimising tensile and fracture behaviour of isotropic and die-drawn PPNCs. Solid-state molecular orientation has been introduced to PPNCs by the die-drawing process. Tensile stress-strain measurements with video-extensometry and tensile fracture of double edge-notched tensile specimens have been used to evaluate the Young¿s modulus at three different strain rates and the total work of fracture toughness at three different notch lengths. The polymer composite was analyzed by differential scanning calorimetry, thermogravimetric analysis, polarizing optical microscopy, wide angle x-ray diffraction, and transmission electron microscopy. 3% and 5% clay systems at various compatibilizer (PPMA) loadings were prepared by three different mixing routes for the isotropic sheets, produced by compression moulding, and tensile bars, produced by injection moulding process. Die-drawn oriented tensile bars were drawn to draw ratio of 2, 3 and 4. The results from the Queen's University Belfast samples showed a decrement in tensile strength at yield. This might be explained by poor bonding, which refers to poor dispersion. Voids that can be supported by intercalated PP/clay phases might be responsible for improvement of elongation at break. The use of PPMA and an intensive mixing regime with a two-step master batch process overcame the compatibility issue and achieved around 40% and 50% increase in modulus for 3% and 5% clay systems respectively. This improvement of the two systems was reduced after drawing to around 15% and 25% compared with drawn PP. The work of fracture is increased either by adding nanoclay or by drawing to low draw ratio, or both. At moderate and high draw ratios, PPNCs may undergo either an increase in the size of microvoids at low clay loading or coalescence of microvoids at high clay loading, eventually leading to an earlier failure than with neat PP. The adoption of PPMA loading using an appropriate mixing route and clay loading can create a balance between the PPMA stiffness effect and the degree of bonding between clay particles and isotropic or oriented polymer molecules. Spherulites size, d-spacing of silicate layers, and nanoparticles distribution of intercalated microtactoids with possible semi-exfoliated particles have been suggested to optimize the final PPNCs property. / SABIC

The strength of leaf fibers and the nutritional value of the edible fruit of several yucca species native to the U.S. southwest were studied to aid in the determination of species best suited for commercial cultivation by the Navajo Nation. The leaves were softened in an autoclave to facilitate the removal of the leaf matrix, conditioned in environmentally controlled chambers, and the fibers were broken using a texture analyzer. The fibers were frozen and cross sectioned and photographed to determine cross sectional area. Official methods were used to determine the nutritional content of the fruit. The mean tensile strength of Y. angustissima, Y. baccata, and Y. glauca was 484 ±79, 710±174, and 388±104 MPa, respectively. Fibers from the leaves of Y. baccata had a significantly higher tensile strength than the leaves of the other two species. Nutritional profiling of the fruit of Y. angustissima and Y. baccata indicated that the fruit of both species are good sources of vitamin C (73-119 mg/100g) and thiamin (0.20 to 0.22 mg/100g). Because of its edible fruit and superior leaf fiber tensile strength, Y. baccata is recommended as the best species for cultivation and commercialization.

Det talas allt oftare om de problem som världens plastanvändning åsamkar miljön genom exempelvis nedskräpning och mikroplaster. Det finns många olika typer och användningsområden för plast. Den typ som anses värst i avseende till miljöpåverkan är plasten som används en gång och sedan förlorar sin funktion, det som idag kallas engångsplast. Ett av de vanligaste områdena där engångsplast används är inom förpackningsindustrin för livsmedel. År 2019/2020 växte en projektidé bland en grupp elever om att se över alternativa förpackningsmaterial till främst frukt och grönt i matvaruhandeln. Idéen utvecklades och vid en expo på Textilhögskolan år 2020 presenterades ett citrusnät för ekologiska citroner stickat på en manuell stickmaskin i pappersgarn. Som fortsättning på arbetet är nu nästa steg att undersöka möjligheterna att sticka en motsvarande prototyp på en industriell maskin och vilka utmaningar som följer. Stickningen genomfördes i Borås på Textilhögskolans trikålabb. Maskinen som användes är en flatsticksmaskin av typen STOLL CMS822 HP knit and wear. Pappersgarn av olika garnnummer kom uteslutande från företaget OJO+ Fibers och baseras på pappersmassa från manillaplantan. Två bindningar stickades, en mesh-bindning och en stickning med flotteringar. Mesh-bindningen testades även med garn av olika garnnummer och olika antal ingående garn. De viktigaste parametrarna för möjligheten att sticka på industriell flatsticksmaskin visade sig vara garnets styrka, styvhet samt maskinens delning. Efter två separata produktionsgenomgångar genomfördes en visuell bedömning som avgjorde vilka stickningar som lämpade sig att gå vidare till ett dragprovstest. Standarden som användes för dragprovstest var (SS-EN ISO 13934–1:2013) och genomfördes på en Tinius Olsen H10KT (Elastocon). Fem provkroppar av varje stickning testades först i torrt- och sedan vått tillstånd genom blötläggning enligt standard. För att jämföra data från dragprovstestningen genomfördes en variansanalys för att upptäcka eventuella skillnader mellan de olika konstruktionerna. Variansanalys genomfördes även inom varje grupp för att undersöka skillnader mellan torra och våta prover av samma konstruktion. Resultatet från dragprovet visar en stor spridning i datamaterialet. På grund av spridningen går det inte att statistiskt säkerställa några slutsatser kring vilken konstruktion som är starkast. Främsta anledningen till spridningen är avvikelser från standarden som var nödvändiga för att genomföra testingen samt faktumet att (SS-EN ISO 13934–1:2013) huvudsakligen är till för vävda varor, ej stickade. Två av mesh-konstruktionerna kunde påvisa signifikant skillnad i mätresultatet mellan de våta respektive torra proverna, som då visade en svag tendens till att de våta proverna klarade högre spänning. Detta kan komma till användning för att enkelt öka garnets styrka vid stickning. / There’s an ongoing worldwide discussion regarding the environmental impact of plastic use. Single- use plastic is considered one of the most problematic due to the loss of functionality after one use. A common industry using single-use plastic is the food packaging industry. In 2019/2020, a project idea grew to review alternative packaging materials for fruits and vegetables. A prototype was presented at the Swedish School av Textile’s expo in 2020, a citrus net hand-knitted in paper yarn for organic lemons. The next step was to investigate the possibility of knitting paper nets on industrial machines and what difficulties may arise. The knitting was carried out in the Textilhögskolan in Borås machine hall on a flat knitting machine, a STOLL CMS822 HP knit and wear. The paper yarn used came exclusively from OJO+ Fibers and was made from pulp from the manilla plant. Two bindings were knitted, one mesh and one with floatations. The mesh binding was knitted in multiple variations, yarn of different yarn numbers and numbers of ingoing yarns. The most important parameters for knitting on industrial machines turned out to be the strength of the yarn, stiffness and gauge of the machine. A visual assessment was carried out after two separate production reviews and determined which knits were suitable to proceed to a tensile test. The standard used for tensile tests was (SS-EN ISO 13934-1:2013) on a Tinius Olsen H10KT (Elastocon). Five specimens of each knit were tested, first in the dry state and then in the wet state. A variance analysis compared the data from the tensile test, partly between the different constructions and between dry and wet samples within each group. The result shows a large spread within the data material, which cannot determine with certainty any conclusions about which construction is the strongest. The main reason for this spread is necessary deviations from the standard and the fact that (SS-EN ISO 13934-1:2013) is mainly for woven goods, not knitted ones. Two mesh constructions demonstrated a significant difference in results between the wet and dry samples. A weak tendency showed wet samples withstanding higher stress than dry ones, which could be a solution to increase the strength of the yarn while knitting.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第24228号 / 工博第5056号 / 新制||工||1789(附属図書館) / 京都大学大学院工学研究科マイクロエンジニアリング専攻 / (主査)教授 土屋 智由, 教授 平方 寛之, 教授 江利口 浩二 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Plast ger otroliga möjligheter i form av stor variation för materialanvändning. Tyvärr sker det dock på bekostnad av miljön då de ackumuleras i naturen. En kompromiss mellan hållbarhet och fortsatt plastanvändning skulle kunna vara att använda biomassa som fyllnadsmaterial i plastkompositer istället för plast. Detta skulle i sin tur minska mängden plast och öka användningen av förnybara råvaror. Naturligtvis måste de mekaniska och termiska egenskaperna också vara av acceptabel kvalitet för materialtillämpningar och helst även erbjuda någon form av uppgradering av det redan existerande materialet. Ett potentiellt fyllnadsmaterial är Woodmer, en LCC (lignin kolhydrat komplex) som produceras av Ecohelix. Woodmers förmåga att agera som ett termoplastiskt kompositmaterial analyserades och jämfördes med de respektive jungfruliga termoplasterna. Tre olika plaster används som bas för kompositerna och dessa plaster var akrylnitril-butadien-styren (ABS), polymjölksyra (PLA) och lågdensitetspolyeten (LDPE). Resultaten visar att det är möjligt att skapa homogena Woodmer/termoplast kompositmaterial. När det gäller de termiska egenskaperna, så gav inte UL 94 någon brandklassificering på materialen, några positiva effekter observerades i TGA och resultaten från DSC var mestadels oförändrade jämfört med respektive jungfrulig plast. Dragprovning visade å andra sidan att de mekaniska egenskaperna påverkas negativt av högre Woodmer tillsatser men effekten varierade kraftigt mellan de olika plasterna då LDPE var minst påverkad och PLA mest påverkad. Framtida forskning bör fokusera på att tillverka material genom dubbelskruv extrudering eftersom det tyvärr fanns problem med blandningen i enkelskruv extrudering. Ytterligare forskning kring materialens morfologi, löslighet och så vidare krävs också för att se om kompositerna är lämpliga material eller om det finns några oförutsedda problem. / Plastics provide incredible opportunities in the form of great versatility for material usage. However, this comes at the cost of environmental issues as they accumulate in the environment. Therefore a compromise between sustainability and continued plastic usage is to use biomass as a filler material in plastic composites instead of virgin plastics. This would in turn reduce the amount of plastic and increase the usage of renewable raw materials. Of course the mechanical and thermal properties must also be of acceptable quality for material applications and preferably even offer some form of improvement to the preexisting material. One potential biomass filler material is Woodmer, a LCC (lignin carbohydrate complex) produced by Ecohelix. The viability of Woodmer as a thermoplastic composite material was analysed and compared to virgin thermoplastics. Three different plastics were used as basis for the composites and these plastics were Acrylonitrile-butadiene-styrene (ABS), polylactic acid (PLA) and low density polyethylene (LDPE). The results show that it is possible to create homogenous Woodmer/thermoplastic composites. As for the thermal properties, while the UL 94 provided no flame classification on the materials some positive effects were observed in TGA and the results from the DSC were similar to the virgin plastics. The tensile test on the other hand showed that the mechanical properties were negatively affected by increasing Woodmer additions but the effect varied substantially between the different plastics as LDPE was the least affected and PLA the most affected. Future research should focus on making the materials through twin screw extrusion as there were unfortunately issues with the mixing from single screw extruders. Further research regarding the materials morphology, solubility and so forth are also required to see if the composites are suitable materials or if there are any unforeseen issues.

Heart valve disease is currently one of the leading forms of heart disease. Current literature has shown that endothelin I, angiotension II and 5-HT are vasoactive agents which cause concentration dependent contractions in aortic valve leaflet tissue. This study tested the mechanical properties of leaflets cut in the radial direction after they were exposed to the agents at varied concentrations or for 0.5, 6 or 24 hours. The elastic modulus, ultimate tensile strength and the yield strength were calculated. In the time trials the elastic modulus and the ultimate tensile strength both showed a significant increase at 24-hours. However, there were no significant differences found between the concentrations. Indicating the amount of vasoactive agent is not as significant as the length of exposure.

This research was conducted to characterize the flexural and tensile characteristics of thin, very high-strength, discontinuously reinforced concrete panels developed by the U.S. Army Engineer Research and Development Center. Panels were produced from a unique blend of cementitous material and fiberglass reinforcing fibers, achieving compressive strength and fracture toughness levels that far exceeded that of typical concrete.The research program included third-point flexural experiments, novel direct tension experiments, implementation of micromechanically based analytical models, and development of finite element numerical models. The experimental, analytical, and numerical efforts were used conjunctively to determine parameters such as elastic modulus, first-crack strength, post-crack modulus and fiber/matrix interfacial bond strength. Furthermore, analytical and numerical models implemented in the work showed potential for use as design tools in future engineered material improvements.

An evaluation of aged hot-mix asphalt (HMA) pavements was accomplished to develop a method for improving the prediction of remaining fatigue life of aged HMA surfaces. This is important for both planning Department of Defense airfield maintenance funds and for predicting the performance of operating surfaces in the theater of operation. This study involved the evaluation of HMA at several military airfields. After field inspections and field testing, slab samples were carried to the U.S. Army Engineer Research and Development Center for laboratory testing. Laboratory testing included the determination of mixture and binder properties, indirect tensile strength tests on cored specimens, and beam fatigue tests. The results from this study were used to develop improved fatigue performance predictions for field-aged HMA pavements.

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