Universiẗat, Diss., 2001--Duisburg.

Techn. Hochsch., Diss., 2003--Aachen.

Techn. Universiẗat, Diss., 2003--Dresden.

Techn. Univ, Diss., 2003--Chemnitz.

Mikroplaster i havet är ett miljöproblem som har fått stor uppmärksamhet i och med nya alarmerande rapporter som publiceras. För lite drygt ett decennium sedan drogs kopplingar mellan mikroplaster i havet och klädindustrin då man funnit mikrofiberföroreringar från polyester och akryl längst med stränder runt om i världen. Redan då kunde man se att mikrofiberkoncentrationen i haven hade ökat i takt med ökad konsumtion av syntetiska material. Forskare är idag överens om att vi vet för lite om vilka effekter mikroplaster i haven har på miljö, vattenlevande organismer och människor. Studier visar att många av de mikroplaster som finns i haven kommer från textilier som släpps ut genom vanlig hushållstvätt, och textilier i polyestermaterial och framför allt fleece tenderar att fälla mer än andra. Syftet med den här studien är att undersöka möjligheterna att avgöra hur ruggningsprocessen vid framställning av fleece påverkar mängden fiberfällning vid tvätt, och även undersöka hur en sänkning av temperatur vid tvätt och kortare tvättid påverkar fiberfällning för fleece. Det finns idag ingen standardiserad metod för att mäta fiberfällning från textilier vid tvätt. Metoden som användes i den här studien har tagits fram utefter tidigare studerad litteratur. En frotté stickades upp på Textilhögskolan i Borås som ruggades till fleece och provbitar skars ut i en storlek på 15x15 cm. Tvätt utfördes i en laboratorietvättmaskin där tvättvattnet filtrerades över ett glasfiberfilter för uppsamling av fibrer. Filtret vägdes efter filtrering för att bestämma fiberfällning. För att undersöka ruggningsprocessens påverkan för fiberfällning vid tvätt jämfördes frotté och fleece. Dessa tvättades i 60 °C i 30 minuter och i tillägg till vägning av filter studerades även dessa i mikroskop. Fiberfällning vid en tid- och temperaturförändring undersöktes för fleece genom att tvättas i två olika temperatur- och tidsinställningar. Resultatet av den här studien visade på ingen signifikant skillnad mellan frotté och fleece och då en färgningsprocess uteslöts var det svårt att urskilja fibrer från fleecelagret i mikroskop. Tid och temperatur visade sig ha betydelse för mängden fiberfällning där provbitar tvättade i 30 minuter visade på högre fiberfällning än prover tvättade i 15 minuter, och prover tvättade i 30 °C visade på högre fiberfällning än de tvättade i 40°C. Brister i den metod som användes i den här studien tros kan ha påverkat resultatet. Vidare forskning är nödvändig för att ta fram en metod för att på ett standardiserat sätt mäta fiberutfällning från textilier vid tvätt för att hitta sätt för att minska mikroplastkoncentrationen i haven.

In 2015, 96.7 million tonnes of textile fibres were produced world-wide. Our high consumption of textiles leads to an increased amount of textile waste. In Sweden, the majority of used clothing and textiles are incinerated due to the lack of recycling techniques. A large amount of post-consumer textile waste is made from blended materials. One of the most common blends, used in as near as all workwear and service textiles, is cotton/polyester. To enable chemical recycling of such textiles, cotton and polyester must first be separated. The aim of this thesis was to separate the materials by depolymerizing the polyester using alkaline hydrolysis. The focus of the work was on how such a process should be performed without a catalyst, in order to result in both a high yield and a high purity of the cotton residue. In order to recycle the residue as a raw material for manufacturing of man-made cellulosic fibres, the cellulose chains in the cotton must also be maintained as unaffected as possible. The polyester in new sheets was completely depolymerized after 390 min at a temperature of 90ºC using a 10% sodium hydroxide concentration and a 1% material-to-liquor concentration. The separation using these conditions gave high yields (above 96%) of the cotton residue regardless of the material fineness used in the process. Furthermore, the separation performed on old sheets show that a pure cotton residue could be produced using higher material concentrations. It was shown that the cotton residue from old sheets, laundered around 50 times, had an intrinsic viscosity comparable to dissolving pulps used for viscose fibre spinning. This study concludes that alkaline hydrolysis without the use of a catalyst could be used to separate cotton and polyester in blended textiles. Furthermore, the findings show that cotton percentage in old sheets only decreased slightly after 50 launderings. Characterization of the materials using ATR FTIR spectroscopy indicate that an integrated textile recycling of hospital bed sheets could be performed since the sheets only contain cotton and polyester in all parts of the sheets.

No description available.

Au cours des dernières décennies, l’utilisation de polymères biodégradables a connu un regain d’intérêt pour des applications agricoles. Dans cette étude, nous nous concentrons sur le développement de textiles biodégradables destinés à la protection anti-insecte des cultures. Actuellement, ces textiles doivent être collectés par des entreprises après la saison agricole et entraîne un coût non négligeable pour l’utilisateur. Une alternative serait d’avoir des agro-textiles qui pourraient être collectés par l’utilisateur et minéralisés après quelques mois. Les polymères biodégradables pourraient répondre à ces objectifs. Dans cette étude, nous nous sommes concentrés sur le poly(butylene succinate) un polymère biodégradable et biosourcé. Le PBS a été synthétisé sur un pilote de polycondensation. Néanmoins, le PBS issu de cette synthèse présente de faibles propriétés rhéologiques. La structure du PBS a donc été modifiée par l’incorporation de branchements ou d’allongeurs de chaines. Les propriétés mécaniques ont également été optimisées via la synthèse de systèmes PBS/PLA transréagits et de PBS nanocomposites. Ces PBS modifiés ont été testés au filage. Finalement un fil de PBS avec 0,5% de silice sphérique a été produit à plus grande échelle et un textile a été fabriqué. Le vieillissement de ces fils PBS a été étudié et la conservation des propriétés mécaniques durant l’utilisation du fil en extérieur a été validée. Enfin, une dernière approche plus exploratoire a été testée. Elle consiste en la modification du PBS par des interactions supramoléculaires réversibles en température. / In the last decade, biodegradable polymers have gained significant interest for agricultural applications. Here we focus on the development of biodegradable textiles for insect-proof nets. Currently these textiles must be collected by specialized companies after the growing season and generate disposal cost. An ideal agrotextile would be collected by the user at the end of the growing season, and undergo full mineralization within few months. These requirements can be achieved by using biodegradable polymers. In this study, poly(butylene succinate) (PBS), a biobased and biodegradable polymer was studied. PBS was synthesized by polycondensation on a pilot plant reactor. Because of low rheological properties of the synthesized polyester, the chemical structure of PBS was modified by several approaches like chain extension or branching. The mechanical properties were tuned with the synthesis of PBS/PLA transreacted systems and PBS nanocomposites. These modified PBS were tested upon fiber spinning. Finally a PBS yarn with 0,5% spherical silica was produced at higher scale and a textile was done. Ageing of the PBS yarns was also studied and the conservation of the mechanical properties during use of the textile was validated. Lastly a more exploratory approach was tested. It is synthesis of modified PBS by supramolecular interactions, which are reversible upon temperature.

Much of the world’s aquatic food webs and nutritional relationships have been blurred by the ever-increasing evidence that many phytoplankton are not exclusively heterotrophic or autotrophic, but instead mixotrophic. Mixotrophy is a continuum of different energy and carbon-acquisition mechanisms utilizing both autotrophy and heterotrophy which distorts the concept of single trophic tier modality. This makes mixotrophs flexible to adapt to environmental pressures and is becoming more the rule than the exception in many aquatic ecosystems. One unique environmental setting where mixotrophy could be highly beneficial to food web stability is in seasonally occurring ephemeral pools – aka vernal pools. Mid-Atlantic vernal pools are biodiverse biogeochemical hotspots and critical breeding habitats for a diverse number of endemic taxa including many endangered amphibian species. Vernal pools are not permanent standing bodies of water and have fluxes in hydrology, temperatures, nutrients, and irradiance to name a few. These extremes make vernal pools an ideal setting for mixotrophic phytoplankton, however it’s never been investigated. Our survey found mixotrophy in every vernal pool sampled, as well as elevated grazing rates in pools experiencing nontypical seasonal conditions. From these small-scale forest pools to the world’s oceans mixotrophy is a widespread nutritional strategy. The Southern Ocean is essential for powering worldwide ocean circulation, regional biogeochemical cycles, and global climate. One of the major hurdles with understanding mixotrophy is identifying the phytoplankton capable of shifting nutritional strategies. While many Southern Ocean plankters have been properly identified as mixotrophic, one such keystone species has gone mislabeled until now. Phaeocystis antarctica is a well-studied Haptophyte algae that plays major roles in the global carbon and sulfur cycles. This species has been historically labeled as an obligate phototroph, but contradictory survives the long dark Antarctic winter without any known evidence of encystment. We suspect that this highly abundant species is in fact mixotrophic, capable of phagocytosis to supplement the irradiance shortcomings of the Antarctic dark. We experimented with varying degrees of light and nutrient limitations to determine possible triggers for P. antarctica grazing. Our results showed P. antarctica ingesting in every treatment, but its highest grazing rates corresponded with limitations to its primary photosynthetic mode. Apart from the newly realized complexity P. antarctica brings to the Southern Ocean food web, it is an environment that suffers from microplastic pollution that can impede these mixotrophic species. Mismanaged plastic waste around the world, especially microfiber discharge from laundered synthetic textiles, escape into the natural environment, and eventually concentrate in the oceans. The Southern Ocean can become disproportionately polluted in regions due to microfibers becoming sequestered once crossing the Antarctic circumpolar current and even becoming trapped in sea-ice formations. While it is easy to see the devastation plastic waste has on megafauna (i.e. turtles, fish, birds, and whales), its microscopic devastation is less obvious. Plastic waste comes in many forms and one less researched form is buoyant polyester microfibers <1mm that interact with colony forming algae. We utilized different concentrations of polyester microfibers and mixing speeds to determine if microfiber interactions with colony formations increases or decreases overall colony buoyancy. Smaller concentrations of polyester microfibers can impart a positively buoyant effect onto P. antarctica colonies regardless of mixing speed, however larger concentrations negatively affected colony buoyancy regardless of mixing speed. / Biology

No description available.