For over 50 years, synthetic petrochemical-based plastics have been produced in ever growing volumes globally and since their first commercial introduction; they have been continually developed with regards to quality, colour, durability, and resistance. With some exceptions, such as polyurethanes, most plastics are very stable and are not readily degraded when they enter the ground as waste, taking decades to biodegrade and therefore are major pollutants of terrestrial and marine ecosystems. During the last thirty years, extensive research has been conducted to develop biodegradable plastics as more environmentally benign alternatives to traditional plastic polymers. Polyvinyl alcohol (PVA) is a water-soluble polymer which has recently attracted interest for the manufacture of biodegradable plastic materials. PVA is widely used as a paper coating, in adhesives and films, as a finishing agent in the textile industries and in forming oxygen impermeable films. Consequently, waste-water can contain a considerable amount of PVA and can contaminate the wider environment where the rate of biodegradation is slow. Despite its growing use, relatively little is known about its degradation and in particular the role of fungi in this process. In this study, a number of fungal strains capable of degrading PVA from uncontaminated soil from eight different sites were isolated by enrichment in mineral salts medium containing PVA as a sole carbon source and subsequently identified by sequencing the ITS and 5.8S rDNA region. The most frequently isolated fungal strains were identified as Galactomyces geotrichum, Trichosporon laibachii, Fimetariella rabenhorsti and Fusarium oxysporum. G. geotrichum was shown to grow and utilise PVA as the sole carbon source with a mean doubling time of ca. 6-7 h and was similar on PVA with molecular weight ranges of 13-23 KDa, 30-50 KDa and 85-124 KDa. When solid PVA films were buried in compost, Galactomyces geotrichum was also found to be the principal colonizing fungus at 25°C, whereas at 45°C and 55°C, the principle species recovered was the thermophile Talaromyces emersonii. ESEM revealed that the surface of the PVA films were heavily covered with fungal mycelia and DGGE analysis of the surface mycelium confirmed that the fungi recovered from the surface of the PVA film constituted the majority of the colonising fungi. When PVA was added to soil at 25°C, and in compost at 25°C and 45°C, terminal restriction fragment length polymorphism (T-RFLP) revealed that the fungal community rapidly changed over two weeks with the appearance of novel species, presumably due to selection for degraders, but returned to a population that was similar to the starting population within six weeks, indicating that PVA contamination causes a temporary shift in the fungal community.

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Dissertation (Ph.D.)--Auburn University, / Abstract. Vita. Includes bibliographic references.

Undergraduate honors paper--Mount Holyoke College, 2005. Dept. of Chemistry. / Includes bibliographical references (leaves 62-65).

Thesis (M.S.)--Oregon State University, 2007. / Printout. Includes bibliographical references. Also available on the World Wide Web.

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 166-176).

Thesis (Ph. D.)--Lehigh University, 2000. / Includes vita. Includes bibliographical references (leaves 41, 81, 130, 183, 270, 315, 336).

Sur la base de précédents travaux de l’unité INSERM 1148, sur des films à base d’alcool polyvinylique, nous avons implanté et évalué des prothèses de moins de 2mm de diamètre. L’ajout de gelatine in vitro a montré des capacités d’adhérence cellulaires, compatibles avec une endothelialisation in situ, des implants garant, d’une perméabilité à long terme. Notre modèle était le remplacement de 1cm d’aorte sous rénale de rat. Ces implants, ont été utilisées comme modèle d’entrainement basse fidélité à la microchirurgie, avec de meilleurs résultats sur l’acquisition de la technique d’anastomose microchirurgicale, que les tubes en silicone antérieurement utilisé, lors de l’enseignement chez 71 étudiants. Un nouveau moyen d’imagerie pour l’exploration vasculaire par angiographie par résonance magnétique, en temps de vol sans injection chez l’animal, et la première application chez l’homme sont rapportés. Apres avoir présenté notre methode de fabrication par reticulation physique (Lyophilisation Congelation) et chimique (STMP) Cdu PVA, directement sous forme de tubes, nous avons confirmé l’hypothèse que les micro implants à base de PVA associé à la gélatine à hauteur de 1%, a permis d’améliorer la perméabilité par rapport au PVA seul, ou à tout autre ratio de gélatine ; et ce grâce à une endothélisation in situ constatées histologiquement. Les performances biomécaniques de l’implant ont aussi étaient évaluées. Au delà de 2 mois la perméabilité chute de 75% à 50%. Le vieillissement du matériel par son enraidissement, et le relargage de la gélatine pourrait expliquer cette diminution des performances au cours du temps. / Non communiqué

Metal-organic framework (MOF) materials are a novel set of porous crystalline materials that have generated great scientific interest within the past two decades due to their attractive properties such as high porosity, surface areas and tunable pore structure. These properties have made them emerge as potential candidates suitable for a broad range of applications such as gas separations and storage, catalysis and drug delivery. Despite their fascinating properties, MOFs are often unsuitable for most industrial applications due to their instability when exposed to mechanical stress. The challenge therefore is to convert the MOFs to high strength materials capable of withstanding such stress while still maintaining their exciting properties. This thesis thus focuses on investigating the effects of different binders on a zirconium based metal-organic-framework, UiO-66, in an attempt to enhance the mechanical strength of the adsorbent samples. Three different binders, kaolinite, polyvinyl alcohol and tartaric acid, are mixed with the parent MOF material in different weight percents, pressed into solid disc pellets at different pressures and calcined at different temperatures. Properties such as changes in structure, density, porosity, surface area, radial crush strength, and the adsorption capacity with CO2 are measured and evaluated. Results gathered from this work reveal that polyvinyl alcohol is the most promising of the three binders due to the increase in the strength of pellets and the slight decrease in CO2 adsorption it offers. Recommendations for future research work aimed at driving these materials towards reaching their maximum application potentials are proposed.