No description available.

No description available.

Plasma polymerisation (PP) is an emerging processing technology with immense potential for future industrial applications, which is increasingly being used for the fabrication of functional coatings on polymeric substrates. In this technique, the solid polymeric film is directly deposited onto the substrate surface to create a new surface of very interesting and unique properties. PP utilizes gas phase chemistries in low-pressure environment to produce well-defined high quality films in controllable and tunable fashion. A major advantage of this process is that it is an environmental safety technique and strategically superior compared to other thin film deposition techniques such as spin coating and spray coating. In general, the quality of the plasma polymer film can be controlled, precisely and reproducible. However, mechanism of the coating under plasma polymerisation is complex and has not yet been completely understood. / The ethylene propylene diene terpolymers (EPDMs) are increasingly being used in numerous technological applications, such as automotive sealing sections (~25kg of elastomer is used in an average car) due to their elasticity. ozone resistance, low weight, ease of fabrication in desired shape/form; favorable mechanical properties and low cost. However, the deficiency of EPDM in the surface specific secondary engineering characteristics that may play a critical role in many applications is encountered. The performance of this elastomeric materials may be further enhanced by deposition of organic surface coatings, which can satisfy one or more surface specific functions including, hydrophobicity, low friction, high abrasion resistance, decorative and protective coatings against harsh terrestrial and/or space environments, etc. / In this PhD thesis the objectives of the research were focused on: (i) creation of low friction and high abrasion resistance ultra thin functional PP coating onto EPDM substrate surface using fluorocarbons and organosilicones as precursors, (ii) investigation of the structure-property-processing relationship of the deposited film in detail, (iii) development of new plasma thin film characterisation and performance evaluation techniques. / Thesis (PhDAppliedScience)--University of South Australia, 2004.

Plasma polymerisation (PP) is an emerging processing technology with immense potential for future industrial applications, which is increasingly being used for the fabrication of functional coatings on polymeric substrates. In this technique, the solid polymeric film is directly deposited onto the substrate surface to create a new surface of very interesting and unique properties. PP utilizes gas phase chemistries in low pressure environment to produce well-defined high quality films in controllable and tunable fashion. A major advantage of this process is that it is an environmental safety technique and strategically superior compared to other thin film deposition techniques such as spin coating and spray coating. In eneral, the quality of the plasma polymer film can be controlled, precisely and reproducible. However, mechanism of the coating under plasma polymerisation is complex and has not yet been completely understood. / PhDAppliedScience

Thesis (Ph.D.)--Tufts University, 1995. / Adviser: Nak-Ho Sung. Submitted to the Dept. of Chemical Engineering. Includes bibliographical references. Access restricted to members of the Tufts University community. Also available via the World Wide Web;

Thesis (doctoral)--Karolinska Institutet, Stockholm, 1994. / Added t.p. with thesis statement inserted. Includes bibliographical references.

Thesis (doctoral)--Karolinska Institutet, Stockholm, 1994. / Added t.p. with thesis statement inserted. Includes bibliographical references.

No description available.

Neste trabalho foi desenvolvido um estudo com o poliéster biodegradável P[3HB] (poli[R-3-hidroxibutirato]) e seu copolímero P[3HB-co-3HV] (poli[R-3-hidroxibutirato-co-3- hidroxivalerato]). Esses materiais são conhecidos por seu grande potencial de biodegradabilidade, porém sua utilização pela indústria ainda é limitada em função de seu baixo desempenho mecânico. Visando a tenacificação desses materiais, optou-se por misturá-los com os elastômeros EPDM (terpolímero de etileno-propileno-dieno) e PVB (Poli(vinil butiral)). Foram estudados quatro grupos de blendas: P[3HB]/EPDM e P[3HB-co- 3HV]/EPDM processados em misturadores internos e posteriormente prensadas em filmes; P[3HB]/EPDM e P[3HB]/PVB extrudados e posteriormente injetados. As blendas foram obtidas nas concentrações de 10, 20 e 30% em peso de elastômeros. Inicialmente, estudou-se efeito da incorporação de elastômeros na cristalinidade, estrutura cristalina, propriedades térmicas e dinâmico-mecânicas das matrizes, e o efeito do tipo de processamento utilizado. Observou-se que a adição dos elastômeros às matrizes semicristalinas aumentou a nucleação de esferulitos, resultando em um aumento da cristalinidade das mesmas. O PVB apresentou um efeito plastificante na estrutura do PHB. Os filmes apresentaram uma degradação térmica maior que as amostras injetadas, resultando em uma cristalização mais lenta e um grau de cristalinidade maior. Em um outro estudo, avaliou-se a morfologia, tensão interfacial, comportamento reológico, propriedades mecânicas e a biodegradabilidade das amostras estudadas. Foi observada uma morfologia de dispersão de gotas para todas as misturas, exceto para a mistura P[3HB]/EPDM obtida por injeção que apresentou um certo grau de co-continuidade. No caso das misturas injetadas foi visto que o fator que parece influenciar mais fortemente em sua morfologia final são as razões de viscosidade observadas entre a matriz e a fase dispersa das mesmas. A adição de elastômeros aumentou a resistência ao impacto do P[3HB], principalmente no caso da mistura P[3HB]/EPDM, o que pode estar relacionado à morfologia co-contínua observada nesta blenda. A incorporação dos elastômeros resultou em uma redução do módulo de elasticidade e da resistência à tração do P[3HB], e aumento do alongamento, principalmente no caso da mistura com PVB. Foi visto que a biodegradação do P[3HB] e P[3HB-co-3HV] aumentou com a adição de elastômeros, devido à morfologia de dispersão e a diminuição do tamanho dos esferulitos que aumentam a área interfacial para a ação das enzimas, facilitando a biodegradação. / In this work a study with the biodegradable polyester P[3HB] (poly[R-3- hydroxybutyrate]) and its copolymer P[3HB-co-3HV] (poly[R-3-hydroxybutyrate-co-3- hydroxyvalerate]) was conducted. These materials are known for their high biodegradability but their use is still limited because of their poor mechanical properties. In order to improve these properties it was chosen to blend these biodegradable polymers with EPDM (Ethylene propylene diene monomer) and PVB (Polyvinyl butyral). Four groups of blends were obtained: P[3HB]/EPDM and P[3HB-co-3HV]/EPDM blends were prepared using an internal mixer and then compressed molded; P[3HB]/PVB and P[3HB]/EPDM blends were prepared using an extruder and further injected. The blend concentrations ranged from 10 to 30 wt. % of the rubbery phase. Initially, the effect of rubber type on the crystallinity, the crystalline structure, thermal and dynamic-mechanical properties of the matrices and the effect of processing method to obtain the blends were investigated. The addition of elastomers on P[3HB] (and P[3HB-co- 3HV]) increases the nucleation, resulting in an increase of matrix crystallinity. PVB showed a plasticizing effect on the P[3HB] structure. Film samples showed a higher thermal degradation than injected ones, resulting in a slower crystallization and higher crystallinity. The morphology, interfacial tension, rheological behavior, mechanical properties (tensile and impact) and biodegradability of samples were also studied. A droplet dispersion morphology type was obtained for all the blends except for P[3HB]/EPDM injected samples which presented some extent of degree of continuity. The experimental results indicated that the final morphology observed for the blends was controlled by the viscosity ratio between the matrix and dispersed phase. Elastomer addition increased P[3HB] impact strength mainly for P[3HB]/EPDM blends, probably due to its co-continuous morphology. Moreover, elastomer incorporation resulted in a decrease of P[3HB] elastic moduli and tensile strength and increase of elongation of break, mainly for P[3HB]/PVB blends. It was observed that P[3HB] and P[3HB-co-3HV] biodegradation increased with elastomer addition due to the droplet dispersion morphology and decrease of spherulites size witch causes an increase of interfacial area for enzymes, facilitating biodegradation.

Orientador: Aldo Eloizo Job / Banca: Clodoaldo Saron / Banca: Elidiane Cipriano Rangel / Banca: Deuber Lincon da Silva Agostini / Banca: Maria Odila Hilario Cioffi / O Programa de Pós Graduação em Ciência e Tecnologia de Materiais, PosMat, tem caráter institucional e integra as atividades de pesquisa em materiais de diversos campi / Resumo: O presente trabalho teve por objetivo o desenvolvimento de compósitos poliméricos através da mistura de resíduo de couro (RC), a ser utilizado como carga, com elastômeros termoplásticos obtidos por meio da compatibilização de polietileno de baixa densidade (PEBD) com borracha natural (BN) obtida a partir do látex de seringueira (clone de Hevera Brasiliensis), juntamente com agentes de cura, visando à vulcanização da BN, para que desta forma se obtivesse melhores propriedades do material. As amostras foram produzidas em um Reômetro de Torque (HAAKE, utilizando rotores tipo roller. Após o processo de reometria, as amostras foram termoprensadas para que ocorresse a vulcanização da fase elastomérica e moldagem dos corpos de prova. Os TPEs e os compósitos foram caracterizados por meio de análises mecânicas, morfológicas, estruturais e térmicas. Diante dos resultados obtidos, pretende-se direcionar o novo material para aplicações tecnológicas a fim de ser utilizado na fabricação peças de automóveis, engrenagens, entre outros. Com este novo material visa-se também direcionar uma aplicação ao resíduo de couro bovino, que é um material abundante e indesejável gerado na industrialização do couro, que pode causar sérios danos ambientais devido ao crono presente em sua estrutura / Abstract: This work aimed at the development of polymr composites by mixing leather waste (RC), to use as filler, with thermoplastic elastomers obtained by the compatibility of low density polyethylene (LDPE) with natural rubber (NR) obtained latex form the rubber tree (NR) obtained latex from the rubber three (Hevea brasileiensis clone), together with curing agents, vulcanizing order to BN, for which thereby obtain the best properties of the material. The samples were produced on a HAAKE torque rheometer using roller type rotors. After the processes of rheometer, samples were pressed to occur term vulcanization of the elastomeric phase and molding of speciments. The TPEs and composites were characterized by means of mechanical, morphological, structural and thermal analysis. Based on these results, we intend to drive new material for technological applications to be used in manufacturing automobile parts, gears, among others. With this new material also pretends to direct an application to the reside of bovide leather, which is an abundant and undersirable material generated in the manufacturing of leather, which can cause serious environmental damage due to the chromium present in its structure / Doutor