A dificuldade de degradação e armazenamento de rejeitos de pneus vem a cada ano intensificando os problemas ambientais, além da proliferação de insetos e roedores, tornando um resíduo danoso à saúde pública. Este trabalho tem como objetivo estudar o efeito da incorporação de resíduos de borracha de pneus nas propriedades físicas e mecânicas de compósitos de matriz polimérica termorrígida, visando à reutilização do resíduo industrial e a obtenção de produtos que atendam aos padrões e normas técnicas da indústria Brasileira. Um planejamento fatorial completo de experimentos do tipo 2 2 3 1 foi utilizado na análise dos resultados. Os fatores experimentais investigados neste trabalho foram: granulometria (30/50 e 100/200 USTyler), fração volumétrica (10, 25 e 50%) das partículas de borracha e adição de anidrido maléico (1,5%) como agente compatibilizante. As variáveis respostas investigadas neste experimento foram: densidade volumétrica, porosidade aparente e resistência à compressão. As partículas 100/00 US-Tyler promoveram maior densidade, aumentando a resistência mecânica dos compósitos. O aumento da fração de borracha reduz a densidade e a resistência mecânica, entretanto, o percentual de 25% exibe propriedades aceitáveis em aplicações de engenharia. O anidrido maléico afetou as propriedades dos compósitos principalmente quando partículas de 30/50 US-Tyler e fração de 10 a 25% de borracha foram adicionadas.Palavras-chave: compósito polimérico, resíduo de borracha, anidrido maléico. ABSTRACTThe difficulty of degradation and storage of rejected tyres has led to increasing environmental problems, beyond the proliferation of insects which may transmit diseases becoming a harmful residue to the public health. This work investigates the physical and mechanical properties of polymeric composites based on tyre rubber wastes in order to achieve a sustainable material which is in accordance with international construction standards. A full factorial design of experiments of type 2 2 3 1 was used to analyze the results.The experimental factors investigated were: particle size (30/50 US-Tyler and 100/200 US-Tyler), volume fraction (10, 25 and 50%) of rubber particles and the addition of maleic anhydride (1.5%) as a compatibilizing agent. The investigated responses in this experiment were: bulk density, apparent porosity and compressive strength. The rubber particles of 100/200 US-Tyler provided the increase of density and strength of the composites. The increase of rubber fraction reduced the density and strength, however, the level of 25% of rubber exhibited acceptable properties for engineering applications. The maleic anhydride
The aim of this study was to characterize the tissue reactions triggered by the polypropylene mesh coated with chitosan and polyethylene glycol film, and if it’s able to prevent the formation of peritoneal adhesions. Defects in the abdominal wall of rats were induced and polypropylene meshes coated with chitosan/polyethylene glycol (CPEG group, n= 12) and uncoated (PP control group, n= 12) were implanted. On the fourth and forty-fifth postoperative day the formation of adhesion and the tissue reaction to the biomaterial was evaluated through histological and histochemical analysis. The area (P= 0.01) and severity (P= 0.002) of the adhesion was significatively less in the CPEG group. On the fourth day the foreign body reaction was less intense in CPEG group (P= 0.018) and the production of collagen fibers was more intense in this group (P= 0.041). The tissue reactions caused by the biomaterials were similar on the 45th day, with the exception of the high organization of collagen fibers in the CPEG group. The CPEG meshes did not fully prevent the formation of adhesions, but minimized the severity of the process. The foreign body reaction promoted by polypropylene meshes coated with CPEG is less intense than that triggered by uncoated polypropylene meshes.
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