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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
331

Biodegradação da blenda poli (ε-caprolactona) e amido de milho adipatado, em diferentes granulometrias, incubada em dois solos / Biodegradation of a poly (ε-caprolactone) and adipate modified corn starch blend, with different granulometries, incubated in two soil types

César, Maria Elda Ferreira 19 April 2007 (has links)
A constatação do crescente acúmulo de lixo, proveniente de plásticos sintéticos que agridem o ecossistema, principalmente o solo, devido ao longo tempo de permanência no ambiente, levou à idéia de desenvolvimento de plásticos biodegradáveis para substituição parcial dos plásticos de origem petroquímica. No presente trabalho, conduzido em laboratório, analisouse a biodegradação da blenda poli (?-caprolactona) e amido de milho adipatado (PCL/A) e do polietileno. Após a etapa de biodegradação foi avaliado o impacto da adição daqueles materiais na microbiota do solo e testada a toxicidade do plástico no solo sobre a emergência e desenvolvimento de plântulas de arroz (Oryza sativa L.), cultivar 202 IAC. Foram usados dois solos: Nitossolo Vermelho eutroférrico com textura argilosa e Argissolo Vermelho Amarelo distrófico com textura arenosa. Os plásticos utilizados no experimento foram incorporados em três diferentes granulometrias: 0,007, 0,196 e 19,5 cm2. Para cada granulometria foram incorporadas ás amostras de solo seis doses de plástico equivalentes a 0, 50, 100, 150, 200 e 250 mg C 100g-1 de solo. O delineamento experimental, para cada solo, foi inteiramente casualizado, com três repetições, em fatorial: na fase de biodegradação: 6 x 2 x 3 (6 doses, 2 plásticos e 3 granulometrias), para as análises microbiológicas e para a fase de toxicidade do plástico no solo 5 x 2 x 1(5 doses, 2 plásticos e 1 granulometria). Cada dose de plástico foi incorporada em 200g de terra dentro de frasco respirométrico hermeticamente fechado a 28°C. A mineralização do plástico foi determinada pela captura de CO2 liberado durante um período de 120 dias. Confirmou-se mais uma vez que o polietileno é um material quase não biodegradável sendo que a dose e a granulometria não afetam sua mineralização. O PCL/A é um material biodegradável. No solo argiloso a maior porcentagem de mineralização foi de 72,47 % e para o arenoso de 60,46%, na granulometria 0,007 cm2 e dose 50 mg C 100g-1 de solo, em 120 dias foi observado que a textura do solo é fator que afeta a mineralização de compostos orgânicos, sendo esta maior em solo de textura argilosa. Nas maiores doses de PCL/A, independentemente do tipo de solo, a porcentagem de biodegradação diminuiu, provavelmente pelo aumento do conteúdo orgânico adicionado, que pode ter suplantado a capacidade de degradação dos microrganismos contidos nos solos. Não houve alterações no carbono e nitrogênio da biomassa microbiana do solo pela adição de polietileno e PCL/A. Em teste de toxicidade do plástico no solo avaliada através da emergência e desenvolvimento de plântulas de arroz (Oryza sativa L.) cultivar 202 IAC, o polietileno e o PCL/A mostraram-se inertes, não alterando a porcentagem de germinação, o índice de velocidade de germinação das sementes, a massa seca da parte aérea e a massa seca da raiz das plântulas. / Evidences of the increasing amount of waste coming from synthetic plastics that damage the ecosystem, mainly the soil, due to their long permanence in the environment, suggested the idea of developing biodegradable plastics in order to partially replace plastic of petrochemical origin. The current trial, accomplished at laboratorial conditions, was firstly developed to analyse the biodegradation of poly (?-caprolactone) and adipate modified corn starch blend (PCL/A) and of polyethylene. After wards e the impact of the addition of these materials on the soil microbiota was evaluated and the toxicity of plastic in the soil during the emergence and development of rice seedlings (Oryza sativa L.) 202 IAC cultivar was tested as well. Two types of soil were used: Red Dusky Podzol with clayey texture and Paleudult (Ultisol) soil with sandy texture. The plastics used in this experiment were added in three different granulometries: 0.007; 0.196 and 19.5 cm2. For each granulometry, six doses were added to the soil samples, 0; 50; 100; 150; 200 and 250 mg C 100g-1 of soil. For each soil, the experiment had a completely randomized factorial design, with three replications: for biodegradation, 6 x 2 x 3 (6 doses, 2 plastics and 3 granulometries); in the microbiological test and in the toxicity test in the soil 5 x 2 x 1(5 doses, 2 plastics and 1 granulometry). Each plastic dose was added to 200g of soil and placed in a hermetically closed respirometric jar at 28°C. The plastic mineralization was determined by CO2 evolution during a 120 day period. Once again it was confirmed that polyethylene is an almost non biodegradable material considering that the dosage and the granulometry do not affect the mineralization. The PCL/A is a biodegradable material. For the clayey soil the mineralization percentage was 72.47 % and for the sandy one, it was 60.46%, in 120 days, for granulometry 0.007 cm2 and dosage 50 mg C 100g-1 of soil. Soil texture affects the kynetics mineralization of the plastic probes, being higher for clayey soil. In the highest dosages of PCL/A, regardless the type of soil, the biodegradation percentage decreased, probably because of the increase in the organic content added, that may have surmounted the degradation capacity of soil microorganisms. There were no changes in the carbon and nitrogen of soil microbiological biomass by adding polyethylene and PCL/A. During the tests of plastic toxicity in the soil, evaluated by the emergence and development of rice seedlings (Oryza sativa L.) 202 IAC cultivar, the polyethylene and the PCL/A showed no effect, without changes on the germination percentage, speed of seed emergence index, shoot and root dry matter mass of seedlings.
332

Avaliação da biodegradabilidade de compósitos à base de poliéster e amido com fibra de coco verde / Evaluation of biodegradable composites based polyester and starch with green cocomut fiber

Lidiane Dias Mazzaro 21 July 2010 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Os materiais poliméricos tem sido uma das causas dos problemas ambientais discutidos em todo mundo nos últimos tempos. Como uma das soluções para esse problema, estão os polímeros biodegradáveis que são materiais que se degradam pela ação de microorganismos. Uma Indústria sediada no Brasil lançou recentemente um poliéster biodegradável que surge boa alternativa para o crescimento no mercado dos polímeros biodegradáveis, principalmente por possuir em sua composição matéria prima de fonte renovável. Neste trabalho foram preparados compósitos com matriz de poliéster biodegradável e fibra de coco verde com e sem modificação química por acetilação em misturador interno Haake. Foi estudada a biodegradabilidade em solo simulado do polímero puro e de seus compósitos e foram avaliadas as propriedades térmicas, morfológicas e mecânicas do polímero puro e de alguns de seus compósitos. O teste de biodegradabilidade foi feito pelo enterro das amostras em solo simulado por períodos distintos, variando de duas a dezessete semanas, seguindo a Norma ASTM G 160 03. Após cada período de teste, as amostras foram retiradas do solo e analisadas por microscopia ótica (MO), microscopia eletrônica de varredura (MEV), análise termogravimétrica (TGA), calorimetria diferencial de varredura (DSC), espectroscopia na região do infravermelho (FTIR) e análise mecânica de tração. Os resultados obtidos indicaram que tanto o polímero puro quanto os seus compósitos sofreram biodegradação, a presença da fibra apenas atrasa o processo de biodegradação, as fibras de coco tiveram uma boa afinidade com a matriz polimérica, a incorporação de 5% fibra de coco na matriz torna o compósito mais rígido e a incorporação da fibra e o processo de biodegradação alteram as características da fase cristalina no material polimérico. / The final disposal of the polymer materials have been one of the causes of environmental problems discussed around the world in recent times. As one of the solutions to this problem comes the biodegradable polymers, which are materials that are degraded by microorganisms. An industry based in Brazil recently lauched a biodegradable polyester that comes good alternative for growth in the market for biodegradable polymer, mainly by having in its composition raw material from renewable resources. In this work, composites were prepared with biodegradable polyester matrix and green coconut fiber with and without chemical modification acetylation internal mixer Haake. The degradation of pure polymer and their composites in simulated soil were evaluated and also the morphology, thermal and mechanical properties of the polymer and some of its composites. The biodegradability test was carried out by burying the samples in simulated soil for different periods ranging from two to seventeen weeks, following the ASTM G 160-03. After each test, samples were removed from the soil and analyzed by optical microscopy (OM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), infrared spectroscopy (FTIR) and analysis of stress strength. The results indicated that both the polymer pure as their composites suffered biodegradation, the presence of the fiber only delays the process of biodegradation. The coconut fibers had affinity with the polymer matrix and the incorporation of 5% coconut fiber in the matrix polyester made it became stiffer. Besides, the incorporation of the fiber and the biodegradation process changes the characteristics of the polymer crystalline phase.
333

Avaliação da biodegradabilidade de misturas poliméricas de policarbonato/poli(-caprolactona) em solo simulado / Evaluation of polycarbonate/poly(caprolactone) polymer blends in simulated soil

Felicia Miranda de Jesus 09 July 2007 (has links)
Neste estudo foram avaliadas amostras de misturas poliméricas de Policarbonato (PC) e Poli--caprolactona (PCL) em diferentes concentrações após enterro em solo preparado, por períodos variando de uma a doze semanas, seguindo a Norma ASTM G 160 - 03. As amostras, após ficarem enterradas, foram retiradas do solo e analisadas por calorimetria diferencial de varredura (DSC), análise termogravimétrica (TGA), microscopia ótica (MO), microscopia eletrônica de varredura (MEV) e espectrometria de absorção na região do infravermelho com transformada de Fourier (FTIR). Foi observado através de avaliação morfológica que houve degradação nas amostras de PCL puro e na mistura PC/PCL (60/40). Para misturas com menores teores de PCL a degradação não foi significativa no tempo de avaliação sugerido pela norma. Após o tempo de 12 semanas em contato com o solo houve uma redução no teor de cristalinidade das amostras tanto de PCL puro quanto da mistura PC/PCL com 40% de PCL. As variações ocorridas devido à biodegradabilidade não foram suficientes para acarretar perda de resistência térmica nas amostras. Verificou-se que para avaliar a biodegradabilidade de misturas contendo o polímero biodegradável PCL, é necessária uma adaptação da Norma utilizada, aumentando o tempo de enterro das amostras / In this study samples of polycarbonate (PC) and poly(- caprolactone (PCL) blends were evaluated in different concentrations after being buried under simulation soil condition, for periods varying from one to twelve weeks, following ASTM G 160 03 methodology. The samples, after being buried, were removed from the soil and analyzed by differential scanning calorimetry (DSC), termogravimetric analysis (TGA), optical microscopy (OM), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). It was observed by morphological evaluation that pure PCL and PC/PCL (60/40) blend have suffered degradation. Blends with lower content of PCL did not shown significant degradation during the period of time suggested at the ASTM methodology. After 12 weeks in contact with soil, pure PCL and PC/PCL blend with 40% of PCL, had a decrease in crystalinity content. The variations in the samples due to biodegradability have not been enough to cause loss of thermal resistance in any of the tested samples. It was verified that to evaluate biodegradability of blends containing biodegradable polymer PCL, it is necessary an adaptation of the ASTM methodology, increasing the time of samples burial
334

Avaliação e caracterização das propriedades filmogênicas de proteínas do soro de leite submetidas à irradiação e modificação de pH / Evaluation and characterization of whey film protein properties submitted to radiation and modification of pH

Fernandes, Ana Paula Stort 14 February 2014 (has links)
Submitted by Marlene Santos (marlene.bc.ufg@gmail.com) on 2014-09-01T20:13:51Z No. of bitstreams: 2 Dissertação Mestrado - Ana Paula Stort Fernandes.pdf: 3677807 bytes, checksum: d2b738bcc2549e7d1ddb1528f875b444 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2014-09-01T20:13:51Z (GMT). No. of bitstreams: 2 Dissertação Mestrado - Ana Paula Stort Fernandes.pdf: 3677807 bytes, checksum: d2b738bcc2549e7d1ddb1528f875b444 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2014-02-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The packages comprise a large part of the daily disposal of household waste and these household waste are the most impactful to the environment. The development of biodegradable packaging material, seeking to replace synthetic polymers, is an approach used in an attempt to reduce the environmental impact caused by the very slow degradation of synthetic material packages. It is known that the development of biomaterials, applicable to various industries technology in the area of packaging, gaining particular attention on the issue of preserving the environment. The aim of this study was to develop a biodegradable films of whey protein irradiated subjected to pH modification, and evaluate their mechanical, optical, structural and barrier properties. The experiment was conducted in the Department of Food Engineering, College of Agronomy, Federal University of Goiás (UFG), located in Goiânia (GO). The protein concentrate, whey was supplied by the Argentine company Arla Foods. Statistical analysis was performed by analysis of variance (ANOVA) and Tukey test (p ≤ 0.05). The computer program Version 2.15.1 R (Vienna, Austria) was used for calculations. In the experiment, all analyzes were performed with three replicates read in triplicate except mechanical tests, in which three replicates were read nine times. It was found that the whey protein had an excellent alternative for the production of biodegradable films. The films were presented translucent, yellowish, with no tendency green and red colors. Movies pH 8.5 had opacity values increased with increasing doses of radiation. The films showed values of pH 5.5 solubility in water below the other, due to the proximity of the isoelectric point of proteins from whey. The pH modification and irradiation process can serve as an alternative to changing the mechanical properties of films based on whey protein concentrate milk and therefore represented an alternative raw material in the preparation of biodegradable films. / As embalagens compõem grande parte dos descartes diários dos resíduos domiciliares e estes resíduos domésticos são os mais impactantes ao meio ambiente. O desenvolvimento de material para embalagem biodegradável, visando substituir polímeros sintéticos, é uma abordagem utilizada na tentativa de reduzir o impacto ambiental provocado pela degradação muito lenta das embalagens de material sintético. Sabe-se que o desenvolvimento de tecnologia de biomateriais, aplicáveis aos vários setores industriais, na área de embalagens, vem ganhando atenção especial em relação à questão da preservação do ambiente. O objetivo desse estudo foi desenvolver filmes biodegradáveis a base de concentrado protéico de soro de leite irradiado submetido a modificações de pH, e avaliar suas propriedades mecânicas, ópticas, estruturais e de barreira. O experimento foi realizado nos laboratórios do Setor de Engenharia de Alimentos, da Escola de Agronomia, da Universidade Federal de Goiás (UFG), localizada em Goiânia (GO). O concentrado protéico de soro de leite foi fornecido pela empresa argentina Arla Foods. A análise estatística dos dados foi efetuada por meio de análises de variância (ANOVA) e do Teste de Tukey (p ≤ 0,05). O programa computacional R versão 2.15.1 (Vienna, Austria) foi utilizado para cálculos. No experimento, todas as análises foram feitas com três repetições lidas em triplicatas com exceção dos testes mecânicos, em que as três repetições foram lidas nove vezes. Concluiu-se que as proteínas de soro de leite apresentaram ser uma excelente alternativa para a produção de filmes biodegradáveis. Os filmes apresentaram-se translúcidos, de coloração amarelada, sem tendência a cores verde e vermelha. Os filmes de pH 8,5 tiveram valores de opacidade aumentados com o incremento das doses de radiação. Os filmes de pH 5,5 apresentaram valores de solubilidade em água inferiores aos demais, devido à proximidade do ponto isoelétrico das proteínas do soro de leite. A modificação de pH e o processo de irradiação podem servir como uma alternativa para alterar as propriedades de filmes a base de concentrado protéico de soro de leite e, conseqüentemente, representaram uma alternativa de matéria-prima na elaboração de filmes biodegradáveis.
335

Digestão anaeróbia de polímero orgânico a base de fécula de mandioca / Anaerobic digestion of organic polymer based on manioc starch

Cremonez, Paulo André 09 February 2015 (has links)
Made available in DSpace on 2017-07-10T15:14:33Z (GMT). No. of bitstreams: 1 DissertacaoPauloCremonez.pdf: 2171148 bytes, checksum: 995ec964a2e225fff5ce8c4199d9738e (MD5) Previous issue date: 2015-02-09 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The increase in the generation and accumulation of solid residues mainly compounds for packaging, led to a search for development technologies of plastics and biodegradable films eligible for treatment by conventional processes used for organic materials. Currently, various plastics, expanded polystyrene and biodegradable films are produced from the most diverse forms. The present work aims to evaluate primarily anaerobic degradation of biodegradable polymers based on manioc starch. The dissertation is divided into two chapters, the first aims at assessing the anaerobic digestion of organic polymer based on manioc starch diluted in residual water of pigs in various concentrations. Meanwhile, the second chapter aims to compare the cassava-based biodegradable polymer with other material widely studied as an additive in the biodigestion process, the glycerol. The anaerobic biodigestion process proves to be effective in the degradation and stabilization of polymeric materials based on cassava and guarantee high rates of production of biogas, rich in methane that can be used for multiple purposes, ensuring energy savings in production processes. The polymer can still be considered interesting additive on digestion processes of other agro-industrial waste aimed at quickly increased production of biogas and showing superior results to other widely used additives as glycerol. Nevertheless, for easy and quick production material degradability of volatile acids, the addition of high concentrations of polymer is not indicated by the possibility of acidification of the reactors. / O aumento na geração e acúmulo de resíduos sólidos compostos principalmente por embalagens, acarretou uma busca por tecnologias de desenvolvimento de plásticos e filmes biodegradáveis passíveis de tratamento a partir de processos convencionais utilizados para materiais orgânicos. Atualmente, diversos plásticos, poliestireno expandido e filmes biodegradáveis, são produzidos das mais diversas formas, sendo que o presente trabalho visa avaliar principalmente a degradação anaeróbia de polímeros biodegradáveis à base de fécula de mandioca. A dissertação é dividida em dois capítulos sendo que o primeiro visa avaliar a digestão anaeróbia de polímero orgânico à base de fécula de mandioca diluído em água residual de suínos em diversas concentrações. Enquanto isso, o segundo capitulo tem por finalidade comparar o polímero biodegradável à base de mandioca com outro material largamente estudado como aditivo no processo de biodigestão, o glicerol. As utilizações de processos de biodigestão anaeróbia mostram-se eficientes na degradação e estabilização de materiais poliméricos a base de mandioca e garantem elevadas taxas de produção de biogás rico em metano, podendo ser utilizado com diversas finalidades energéticas, garantindo economia em processos produtivos. O polímero ainda pode ser considerado interessante aditivo em processos de digestão de outros resíduos agroindustriais visando-se rápido aumento da produção de biogás e apresentando resultados superiores a outros aditivos largamente empregados como o glicerol. Apesar disso, pela fácil degradabilidade do material e rápida produção de ácidos voláteis, a adição de altas concentrações de polímero não é indicada pela possibilidade de acidificação dos reatores
336

Controle da composição do copolímero P3HB-co-3HHx por indução gradativa da expressão dos genes phaA e phaB em Pseudomonas sp. LFM461. / Composition control of P3HB-co-3HHx through gradative expression of phaA and phaB genes in Pseudomonas sp. LFM461.

Cespedes, Lucas Garbini 25 October 2016 (has links)
Os copolímeros de 3-hidroxibutirato e 3-hidroxihexanoato (P3HB-co-3HHx) são da família dos polihidroxialcanoatos (PHA), materiais termoplásticos e biodegradáveis acumulados por bactérias a partir de fontes de carbono renováveis. O P3HB-co-3HHx desperta interesse industrial para frações de 3HHx menores que 20 mol%, assemelhando-se ao polietileno de baixa densidade. Neste projeto, criou-se um sistema genético para controlar a composição do copolímero P3HB-co-3HHx pela indução de genes da biossíntese de precursores 3HB. Baseado no promotor lac foram construídas cinco versões do plasmídeo de controle de copolímero (pCC) utilizando o promotor Lac. Porém, mesmo com a versão mais aprimorada, não foi possível o controle de composição de P3HB-co-3HHx em Pseudomonas sp. LFM461. Através de experimentos de atividade enzimática e RT-qPCR do cDNA do gene phaA e phaB, foi possível indicar que o problema está na impossibilidade do promotor Lac de promover expressão dos genes de biossíntese de 3HB presentes nos pCC. / Polyhydroxyalkanoates (PHA) are polyesters material accumulated by bacteria which has thermoplastic and biodegradable proprieties and can be produced from renewable feedstocks. Copolymers of 3-hydroxybutirate and 3-hydroxyhexanoate (P3HB-co¬-3HHx) which contain less than 20mol% of 3HHx have being researched for its industrial proprieties. Recently, our laboratory has been researching a Pseudomonas sp. strain, LFM461, which can produce high 3HHx content when hosting PHA biosynthesis genes from Aeromonas. In this project, it was design a genetic system for control of P3HB-co-3HHX composition through induction of 3HB monomers biosynthesis. Thus, five versions of a copolymer control plasmid (pCC) was built based on Lac promoter. However, even through improvements on stability and expression profile of pCC it was not possible to stablish an assay of successful PHA composition control in Pseudomonas sp. LFM461. By enzymatic activity and RT-qPCR of cDNA experiments we have indications of problems of Lac promoter on driving the expression of 3HB genes in pCC.
337

Copolímeros estatísticos biodegradáveis de epsilon-caprolactona e L,L-dilactídeo - síntese, caracterização e propriedades. / Biodegradable statistical copolimers of epsilon-caprolactone e L,L-lactide - synthesis, caracterization and properties.

Castro, Maria Leonora de 07 April 2006 (has links)
Copolímeros de e-caprolactona e l,l-dilactídeo têm sido investigados com a finalidade de desenvolver materiais biodegradáveis para aplicações médicas. As sínteses dos homopolímeros e copolímeros de epsilon-caprolactona e l,l-dilactídeo por abertura de anel e polimerização em massa transcorreram a 120oC sob atmosfera de nitrogênio, usando o octanoato de estanho como iniciador. A composição dos copolímeros variou de 5,90% a 97,30% em massa de l,l-dilactídeo. As massas molares dos polímeros sintetizados foram determinadas por viscosimetria capilar e cromatografia de permeação em gel (GPC). A composição dos copolímeros foi determinada por RMN de 13C. As propriedades térmicas e mecânicas foram avaliadas por DSC e DMTA. O grau de cristalinidade e as fases cristalinas dos copolímeros foram determinados por difração de raios X (WAXS). Foram observadas altas taxas de conversão de monômeros para os homopolímeros e para os copolímeros Co60 ao Co90 (taxas de 70-80%). Os homopolímeros e copolímeros sintetizados apresentaram altas massas molares (M w até 106.500 g/mol para os copolímeros) e moderada polidispersidade (1,50). As análises de RMN de 13C demonstraram a predominância da formação de copolímeros estatísticos e a ausência da transesterificação durante a polimerização em massa. As propriedades dinâmico-mecânicas foram fortemente dependentes da estrutura cristalina e do grau de cristalinidade dos copolímeros. Os copolímeros sintetizados apresentaram propriedades mecânicas variando do flexível ao rígido termoplástico. Os copolímeros com composição próxima a equimolar (Co30 ao Co40) apresentaram os mais baixos graus de cristalinidade (13 a 15%) e, por conseqüência, apresentaram maior taxa de degradação (20% em 408 horas para o Co40), em comparação com os demais copolímeros. / Copolymers of epsilon-caprolactone with l,l-lactide have been investigated in order to develop biodegradable materials for medical applications. The synthesis of homopolymers and copolymers of e-caprolactone with l,l-lactide by ring-opening bulk polymerization was performed using stannous octoate as initiator at 120 ºC under nitrogen atmosphere. The copolymers composition was varied from 5.90 to 97.30 % in mass of l,l-lactide. The molecular weight of synthesized polymers were determined by viscometry and GPC. The copolymers composition was determined by 13C NMR. Thermal and mechanical properties have been evaluated by DSC and DMTA. The degree of crystallinity and the crystalline phase of copolymers were determined by WAXS. High conversion was observed for homopolymers and copolymers Co60 to Co90 of l,l-lactide (70-80%). The homopolymers and copolymers presented hight molecular weight (M w up to 106,500 g/mol for copolymers) and low polydispersivity (1,50). The analyses by 13C- NMR spectroscopy have shown the predominance of statistical copolymers formation and the transesterification reaction did not occur during the bulk polymerization. Thermal and mechanical properties were dependent on the crystalline phase and of the degree of crystallinity. The synthesized copolymers presented mechanical properties from rubbery to stiff thermoplastics. The copolymers with equimolar composition presented low degree of crystallinity (13 ? 15%) and higher degradation (20% during 408 hours for Co40).
338

What would be the efficient ways for Switch Pac to increase potential demand and capitalize on green attitudes and behavior in the Swedish market?

Curtolo, Anna, Bruning, Andrea January 2008 (has links)
<p>Date: 6/16/2008</p><p>Institution: School of Sustainable Development of Society and Technology, Mälardalen University, Västerås (Sweden)</p><p>Authors:</p><p>Brüning, Andrea</p><p>830111</p><p>Västerås</p><p>Curtolo,Anna</p><p>820517</p><p>Västerås</p><p>Tutor: Tobias Eltebrandt</p><p>Title: A Study of Switch Pac: what would be the efficient ways for Switch Pac to increase potential demand and capitalize on green attitudes and behavior in the Swedish market?</p><p>Problem: What would be the efficient ways for Switch Pac to increase potential demand and capitalize on green attitudes and behavior in the Swedish market?</p><p>Purpose: The aim of our project is to see the potential of Switch Pac’s oxo-biodegradable plastic bags on the Swedish market by capitalize on green attitudes and behaviour.</p><p>Method: The report is based on primary data collected through questionnaires (end consumer/ B2B customers). For the investigation of Switch Pac’s macro- and microenvironment secondary data was used (books, journals, newspaper and the Internet)</p><p>Conceptual Framework: The conceptual framework consists of certain models to investigate the following topics:</p><p>Consumer behavior</p><p>AIDA-Model</p><p>STP-Model</p><p>Switch Pac´s business environment</p><p>PESTEL</p><p>Conclusion/ Recommendations: In our conclusion based on our frameworks PESTEL, AIDA and STP we concluded that peoples’ awareness regarding environmental friendly plastic bags are not very high based on our questionnaire. The efficient ways for Switch Pac to increase potential demand is to target the customer in the age range from 20 – 49 years and cooperate with supermarkets and (department) stores. Furthermore, Switch Pac needs to position its products in the consumers mind through create brand awareness by using certain elements of the marketing mix model.</p>
339

Development of a New Oral Vaccine against Diphtheria and the Study of its Immunogenicity in Mouse and Man

Rydell, Niclas January 2004 (has links)
<p>Most pathogens enter the body via mucosal surfaces. In contrast to parenterally administered vaccination, mucosal vaccination has the advantage of eliciting both a systemic and a local mucosal immune response. An oral biodegradable adjuvant with these features would have great potential. </p><p>This thesis has focused on the development of a new oral vaccine against diphtheria. Biodegradable polyacryl starch microparticles were used as a mucosal adjuvant. Diphtheria toxin or cross-reacting material of diphtheria toxin (CRM197) was covalently conjugated to the microparticles and fed to mice by oral gavage. Formaldehyde treatment was also studied as a means of either detoxifying (diphtheria toxin) or stabilising (CRM197) these formulations. All formulations given to mice orally or parenterally, but not intranasally, induced a strong systemic immune response and diphtheria toxin neutralising antibodies. Only formulations administered orally induced a mucosal IgA response as well. </p><p>The non-toxic recombinant protein CRM197 proved to be a promising antigen candidate in an oral diphtheria vaccine when conjugated to the microparticles. Mild treatment of CRM197 with formaldehyde before conjugation to the starch microparticles potentiated the immunogenicity of the formulation. However, no immune response was detected in healthy volunteers after administration of this vaccine in a phase I trial. The possible reasons for the difference in response between mouse and man are discussed.</p><p>The use of cDNA expression macro array technology was also evaluated as a tool in vaccine-related research. Tetanus toxoid and aluminium phosphate were used as model parenteral antigen and adjuvant. It was concluded that the antigen modulates the molecular mechanisms of the aluminium phosphate adjuvant to a greater extent than previously recognised.</p>
340

Development of a New Oral Vaccine against Diphtheria and the Study of its Immunogenicity in Mouse and Man

Rydell, Niclas January 2004 (has links)
Most pathogens enter the body via mucosal surfaces. In contrast to parenterally administered vaccination, mucosal vaccination has the advantage of eliciting both a systemic and a local mucosal immune response. An oral biodegradable adjuvant with these features would have great potential. This thesis has focused on the development of a new oral vaccine against diphtheria. Biodegradable polyacryl starch microparticles were used as a mucosal adjuvant. Diphtheria toxin or cross-reacting material of diphtheria toxin (CRM197) was covalently conjugated to the microparticles and fed to mice by oral gavage. Formaldehyde treatment was also studied as a means of either detoxifying (diphtheria toxin) or stabilising (CRM197) these formulations. All formulations given to mice orally or parenterally, but not intranasally, induced a strong systemic immune response and diphtheria toxin neutralising antibodies. Only formulations administered orally induced a mucosal IgA response as well. The non-toxic recombinant protein CRM197 proved to be a promising antigen candidate in an oral diphtheria vaccine when conjugated to the microparticles. Mild treatment of CRM197 with formaldehyde before conjugation to the starch microparticles potentiated the immunogenicity of the formulation. However, no immune response was detected in healthy volunteers after administration of this vaccine in a phase I trial. The possible reasons for the difference in response between mouse and man are discussed. The use of cDNA expression macro array technology was also evaluated as a tool in vaccine-related research. Tetanus toxoid and aluminium phosphate were used as model parenteral antigen and adjuvant. It was concluded that the antigen modulates the molecular mechanisms of the aluminium phosphate adjuvant to a greater extent than previously recognised.

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