Navegando por Palavras-chave "Blenda"

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    Desenvolvimento de blendas de polímeros estímulo-resposta baseadas em Poli (N-vinilcaprolactama-co-acrilato de N-butila) e poli(3-hexiltiofeno)
    (Universidade Federal de São Paulo (UNIFESP), 2019-02-20) Nahra, Sara Robert [UNIFESP]; Cristovan, Fernando Henrique [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Conductive polymers discovered in the late 1970s allowed a revolution in the construction of electronic devices, such as rechargeable batteries, photovoltaic cells, among others. Today, these materials have been extensively studied to replace traditional materials in the construction of such devices. In addition, these materials stimulate the adhesion and proliferation of several cell types in biocompatible materials, being able to be used in tissue engineering. However, there are no studies reported for this application. A good material for use as a biomaterial is poly(Nvinylcaprolactam) (PNVCL), which is biocompatible, temperature sensitive and has good mechanical strength, together with poly (3-hexylthiophene), P3HT, which allowed conductive properties to the blend. Due to the characteristics that result in high flexibility, the production of the copolymer with N-vinylcaprolactam (NVCL) and butyl acrylate (Abu) monomer result in high stiffness of NVCL resulting in a more flexible material suitable for health applications. In this project, the syntheses of PNVCL, poly(N-vinylcaprolactam-co-butyl acrylate) [P(NVCL-co-ABu)] and poly(3- hexylthiophene) (P3HT) were performed. The polythiophene (PT) blends were prepared with P(NVCL-co-ABu) by solution, films were obtained by casting and mats were processed by electrospinning. From Fourier Transform Infrared (FT-IR) analysis it was confirmed that blends were formed between P3HT and PNVCL. Through the electrical tests, it showed the samples to be quite resistive. The cytotoxicity tests showed that the conductive polymer increased the cellular viability of the material, even the blends with no electrical conductivity. From the DTG plot, it was found that the presence of P3HT in the copolymer or polymer did not significantly affect the degradation of the material. DSC analysis showed that the presence of P3HT significantly decreased the Tg (from 120 °C to 80 °C) for the polymers with the highest proportion of NVCL in the copolymer and significantly increased the Tg value for the polymers with the highest ABu ratio. It was possible to find the formation of mats for PNVCL, for P3HT/PNVCL and for P3HT/P(NVCL-co-ABu) blends with 25 and 20% ABu using appropriated processing conditions.
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    Estudo da produção e reciclagem de blendas de polietileno e amido termoplástico visando aplicações no setor de embalagens
    (Universidade Federal de São Paulo, 2022-10-31) Santos, Natali Bomfim [UNIFESP]; Lemes, Ana Paula [UNIFESP]; http://lattes.cnpq.br/4529102387970131; https://lattes.cnpq.br/8019096371841292
    Nesse trabalho, blendas de polietileno de baixa densidade (LDPE) e amido termoplástico (TPS) foram produzidos variando-se a proporção entre esses componentes, sem e com a utilização do LLDPE-g-MA como agente compatibilizante. Primeiramente o TPS foi preparado realizando-se a plastificação do amido com glicerol, em uma extrusora dupla rosca. As blendas de LDPE e TPS também foram preparadas em uma extrusora dupla rosca. As blendas com e sem adição de agente compatibilizante foram preparadas variando a proporção do TPS de 10 a 70% em massa. As blendas LDPE/TPS e LDPE/LLDPE-g-MA/TPS foram caracterizadas com relação a suas propriedades mecânicas por meio de ensaios de tração e impacto, propriedades térmicas, por meio de análise termogravimétrica (TGA) e calorimetria exploratória diferencial (DSC), ensaio de difração de raio-X (DRX), microscopia eletrônica de varredura (MEV), espectroscopia de infravermelho com transformada de Fourier (FT-IR) e avaliação da molhabilidade dos filmes pelo método da gota séssil. Também foi realizado um estudo sobre a reciclagem das blendas de LDPE/TPS e LDPE/LLDPE-g-MA/TPS, utilizando-se duas rotas. Na primeira as blendas produzidas foram submetidas a dois novos ciclos de reprocessamento em extrusora com obtenção de corpos de prova por moldagem por compressão com aquecimento. Na segunda rota foi realizada uma etapa de lavagem para remoção do amido, e avaliado a viabilidade de reinserção do LDPE pós lavagem num novo processamento.
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    Preparação e caracterização de filmes fotoluminescentes de blenda polifluoreno/borracha nitrílixa (PF/NBR)
    (Universidade Federal de São Paulo, 2013-04-06) Barbosa, Camila Gouveia [UNIFESP]; Philadelphi, Laura Oliveira Peres [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    With the objective of obtaining homogeneous and stable films of polyfluorene, with low excimer formation in the solid state, the copolymer poly[(9,9-dioctylfluorene)-co-phenylene] (PF) was synthesized via the Suzuki reaction and incorporated in an elastomeric matrix (nitrile rubber – NBR); films of the polymeric blend were prepared based on the proportions of 1, 5, 10, 20 and 50 % (m/m) of PF in NBR. The films were prepared using casting, spin coating and Langmuir-Blodgett. The results of the characterization techniques performed in this study indicate that it was possible to obtain a more stable material, without changes in the luminescent properties of PF, with lower excimer formation in the solid state and with an increase of the effective conjugation of the polymer. Besides that, the nitrile rubber was fundamental for the preparation of homogeneous films, using the three methodologies presented.