Resumo: Neste trabalho foi avaliada a influência do tratamento de fibras de bagaço de cana-de-açúcar nas propriedades mecânicas e dinâmico-mecânicas, na estabilidade térmica, na densidade e absorção de água, quando utilizadas na preparação de compósitos com resinas de poliéster insaturado em comparação com a resina sem reforço. As fibras foram submetidas a tratamento químico com solução alcalina de hidróxido de sódio. O tratamento melhorou as propriedades de impacto, aumentou o módulo de elasticidade em flexão, não alterou significativamente o módulo de elasticidade em tração dos compósitos em relação à resina sem reforço e melhorou a compatibilidade fibra matriz quando comparada com compósitos com a fibra sem tratamento, o que pode ser observado nas fraturas de impacto analisadas por microscopia eletrônica de varredura. As superfícies das fibras também foram avaliadas por microscopia eletrônica de varredura. Palavras-chave: Resina de poliéster insaturado, bagaço de cana-de-açúcar, mercerização, propriedades mecânicas, propriedades dinâmico-mecânicas, adesão fibra-matriz. Unsaturated Polyester Resin Composite with Sugar Cane Bagasse: Influence of Treatment on the Fibers Properties Abstract: The aim of this work is to evaluate the influence of the sugar cane bagasse NaOH treatment in the mechanical and dynamic-mechanical properties, in the thermal stability, density and water absorption, when used in unsaturated polyester resin/sugar cane bagasse composite. The sugar cane bagasse was submitted to the chemical treatment with alkaline solution of NaOH. The treatment improves the impact and flexural elasticity modulus when compared with resin without fibers, in addition to the adhesion of the fibers with the matrices, but does not improve significantly the tensile elasticity modulus. The surfaces of the impact fracture were analyzed by SEM. Keywords: Unsaturated polyester resin, sugar cane bagasse, mercerization, mechanical properties, dynamic mechanical properties, fiber-matrix adhesion. IntroduçãoAtualmente muitas pesquisas têm avaliado a viabilidade da utilização de fibras naturais como uma alternativa para as fibras sintéticas convencionalmente utilizadas como reforço em materiais compósitos de matriz polimérica. Este interesse se deve à necessidade de se encontrar fontes renováveis de matéria-prima, de reduzir o impacto ambiental dos materiais e reduzir custos [1][2][3][4][5][6][7][8][9][10] . Fibras celulósicas como bagaço de cana-de-açúcar, sisal, banana, coco, madeira e juta, têm sido incorporadas em vários termoplásticos e termofixos como reforço ou carga [11] . As resinas termofixas são muito empregadas devido às diversas vantagens como: baixo custo, estabilidade térmica e dimensional, resistência química a altas temperaturas e facilidade de se moldar peças com grandes dimensões; no entanto a sua baixa resistência à fratura torna necessária a utilização de reforços.Joshi et al. avaliaram o ciclo de vida de compósitos com diferentes fibras naturais em relação a um compósito com fibras de vidro e chegara...
It is well known that calcium phosphate compounds are widely used as bone substitute due to their biocompatibility and bioactivity. Furthermore, recent studies have shown that slight changes in morphology or crystal structure can lead to several in vivo behaviours. Therefore, the purpose of this study was to investigate two different β-TCP synthesis routes (solid state reaction and aqueous solution precipitation) and their consequences on the final cement properties. It was found out that both routes are equivalent as there were no significant differences on their cement properties, except for mechanical resistance. The latter difference can also be attributed to the difference on the particle size distributions of the obtained β-TCP. These facts indicate that solid state reaction route is more interesting given its simplicity and yield.
The biological behavior of a new bioactive material composed of calcium-deficient hydroxyapatite, octacalcium phosphate, and β-tricalcium phosphate was investigated by in vitro indirect and direct cytotoxicity, cell adhesion and proliferation tests, and by in vivo subcutaneous and bone implantation in rats. The results of the in vitro studies showed that the material is biocompatible and no cytotoxic. Slightly poorer initial cell adhesion and lower cell proliferation than in control was observed, which were attributed to the reactivity and roughness of the material surface. In vivo results showed that the material is biodegradable and bioactive in bone tissue, but only biocompatible and partially biodegradable in soft tissue.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.