Composites consisting of waste cotton yarn (CF) from the textile industry and postconsumer expanded polystyrene (EPS) was followed during 90 days of exposure in simulated soil. The mechanical properties, morphologies and chemical natures of the composites were determined before and after exposure in simulated soil. The composites were made using a single-screw extrusion, a twin-screw extrusion and injection molding. The composites showed an increase of the mechanical properties nearly 50% in relation to the recycled expanded polystyrene (rEPS). After exposure in simulated soil the composites presented losses of mechanical properties. Evidence of the oxidation of the samples was demonstrated by the increase in the values of the carbonyl index after 30 days of exposure in simulated soil. Changes in the color of the surface of the sample were observed after 90 days of exposure and are due to the fungi and bacteria colonization on the surface.

Styrene-butadiene rubber (SBR) has large applications in the shoe industry, especially as expanded sheets used to produce insoles and inner soles. According to TG analysis, the rubber content in SBR residues (SBR-r) was found to be around 26-wt%. Based on that data, a cost-effective technique for the reuse of SBR-r in Nitrile rubber (NBR) was developed. Later, the effect of SBR-r on the cure behavior, mechanical performance, swelling, and crosslink density of reused rubber was investigated, with more emphasis placed on the effect of both particle size and loading of waste filler. Cure characteristics such as optimum cure time and scorch time were then reduced by the increasing amount of SBR-r filler. Owing to the reinforced nature of the largest particle size SBR-r, the best results for the mechanical properties of NBR were those in which SBR-r was added at the end of the cure process. The study has thus shown that SBR residue (SBR-r) can be used as an economical alternative filler in NBR.

O poli[(etileno)-co-(acetato de vinila)] (EVA) possui grande aplicação na indústria calçadista, sendo utilizado na confecção de placas expandidas para posterior corte de palmilhas e entressolas. Estudos realizados na região sul do Brasil mostraram que os resíduos gerados pela indústria calçadista foram superiores a 200 toneladas/mês em 2001, sendo o maior volume oriundo de recortes de placas expandidas. Por isso, o objetivo deste trabalho foi o de caracterizar resíduos de EVA de chapas expandidas, visando à reciclagem mecânica desse material. Análises em MEV demonstraram que o resíduo de EVA apresenta uma morfologia microcelular que é destruída após o processo de moagem. O resíduo de EVA moído apresenta duas fases, uma reticulada (matriz) e uma não-reticulada (dispersa). O resíduo de EVA apresentou teor de gel de aproximadamente 75% em massa, cerca de 20% em massa de acetato de vinila (VAc), fora processado a partir de EVA com aproximadamente 28% de VAc e possui teor de carga inorgânica de 20% em massa, segundo análises em TGA. O EVA resíduo apresentou maiores valores de módulo elástico e de dureza, e menores valores de elongação na ruptura e de resistência ao impacto Izod. O custo energético da moagem do resíduo de EVA foi calculado como sendo inferior a 5% do valor do EVA virgem.

Poly[(ethylene)-co-(vinyl acetate)] (EVA) has large application in the shoes industries, especially as expanded sheets, in order to produce insoles and innersoles. Studies carried out in the south region of Brazil in 2001 have demonstrated that the residues generated by shoes industries were higher than 200 ton/month, the major part of which is composed by EVA expanded sheets. With this in mind, the objective of this work was to characterize the residues of expanded EVA and also to analyze the milling cost in order to make the recycling possible. The EVA residues presented originally a microcellular structure, which was destroyed after milling, according to SEM analysis. The EVA powder was found to be composed by two phases: a crosslinked phase (75wt%) and a soluble one (25wt%). The VAc content in EVA residues was found to be around 20wt% and it is believed that the EVA had originally ca. 28wt% of VAc before the crosslinking process, according to the TG analysis. Besides, it was found that the crosslinked structure of EVA residues make them stiffer than virgin EVA used for comparison, according to mechanical tests. The milling cost was estimated to be less than 5% compared to the virgin EVA.

Visando o aproveitamento de resíduos de laminados de poliéster insaturado com fibra de vidro, foi realizado o estudo da incorporação do resíduo moído em placas confeccionadas à base de resina poliéster insaturado pelo processo de moldagem por compressão de preformas (BMC). Foram testadas cinco formulações com diferentes quantidades de resina poliéster, resíduo moído, aditivos e cargas. As placas foram confeccionadas em prensa hidráulica com molde plano e pressões da ordem de 18,1 MPa à temperatura de 115 ºC. Os corpos de prova, preparados segundo normas ASTM, foram submetidos a ensaios de tração, impacto Charpy e dureza do material. Os resultados dos ensaios mecânicos indicam que a substituição de fibra de vidro pelo resíduo moído no compósito polimérico promove perda de resistência à flexão, ao impacto Charpy e a dureza do compósito; a resistência à tração mostra que a incorporação do resíduo pode ter um aumento de 23% quando a quantidade de resíduo adicionada é de 20% p/p.

In this work we studied the incorporation of fiberglass residues in plates made of insatured polyester resin by bulk molding compound process (BMC). Five different mixtures were made and their mechanical properties were determined. The results showed that using residues instead of fiberglas produces a decrease of the flexural strength, Charpy impact strength and hardness; however depending on the percentage of residue, the tensile strength may have a significant increase.