Divânia Ferreira da Silva

Influence of SEBS-MA and SBS compatibilizers on properties and morphology of blends of polystyrene/rubber residue (SBRr) from the footwear industry

Abstract The reuse of rubber waste is very important today, both to reduce the harm-ful effects on the environment, and to reduce the cost of new material development. Considering that most of the studies reported in literature refer to the reuse of tire waste, this article aims to evaluate the influence of styrene-butadiene-styrene (SBS) and styrene-(ethylene-butylene)-styrene grafted with maleic anhydride (SEBS-MA) compatibilizers on the blend performance of polystyrene (PS)/styrene-butadiene rub-ber residue (SBRr), which come from the footwear industry. The blends were prepared in a co-rotating twin screw extruder and then were molded by injection. They were analyzed by impact and tensile tests, heat deflection temperature (HDT), ductile-brittle transition temperature, dynamic mechanical thermal analysis (DMTA) and transmis-sion electron microscopy (TEM). The results evidenced that the use of any of the com -patibilizers on the PS/SBRr blend significantly increased the impact strength, while the tensile properties and HDT were lower when compared to the polymer matrix. The ductile-brittle transition temperature remains at approximately 25°C range for all the blends. In general, it has been proved that the SBS was the most effective compatibiliza -tion process in the PS/SBRr system. The DMTA test shows the presence of two distinct temperature peaks. The morphologies obtained by TEM of binary and ternary blends were quite different and typical of immiscible blend. The results show a good perspec -tive regarding the use of industrial waste (SBRr), since it may enhance a material that would be discarded.

Efeito dos agentes de compatibilização SBS e SEBS-MA no desempenho de misturas de poliestireno/resíduo de borracha de SBR

O reaproveitamento de residuos de borracha e de extrema importância atualmente, tanto para minimizar os efeitos nocivos no meio ambiente, quanto para reduzir o custo no desenvolvimento de novos materiais. Considerando que a maioria dos trabalhos relatados na literatura se refere ao reaproveitamento dos residuos de pneus, o presente trabalho tem como objetivo avaliar a influencia dos compatibilizantes SBS e SEBS-MA no desempenho da mistura de PS/residuo de borracha da industria de calcado (SBR), utilizando 5% em peso destes compatibilizantes. As misturas inicialmente foram preparadas em uma extrusora de rosca dupla corrotacional e, posteriormente, os grânulos extrudados moldados por injecao. Estas foram analisadas por ensaios de impacto, flexao, temperatura de deflexao termica (HDT), termogravimetria (TG) e microscopia eletronica de varredura (MEV). Os resultados evidenciaram que a utilizacao de qualquer um dos compatibilizantes na mistura PS/SBR aumentou expressivamente a resistencia ao impacto, enquanto que as propriedades de flexao e HDT foram inferiores em relacao a matriz polimerica. Em geral, ficou comprovado que o SBS e mais eficaz no processo de compatibilizacao do sistema PS/SBR, aumentando em 320% a resistencia ao impacto em relacao ao PS, bem como tendo uma perda de apenas 10,9% da HDT. Os resultados de termogravimetria ilustraram que a mistura PS/residuo apresentou uma maior estabilidade termica, em relacao ao PS puro, para temperatura superior a 376oC. As morfologias apresentadas pelas misturas ternaria e binaria foram bastante diferentes e tipicas de misturas imisciveis. Estes resultados mostram uma boa perspectiva de uso destes rejeitos industriais (SBR), uma vez que se pode valorizar um material que seria descartado. Alem disso, tem a possibilidade de desenvolver um novo material com boas propriedades, bem como minimizar o efeito negativo desses rejeitos nos ecossistemas.

Analysis of Used Vegetable Oils Treated with Paraíba/Brazil Clays by Kinematic Viscosity

The search for new sources of renewable energy order to minimize environmental impacts has led the scientists to develop new alternatives, such as the use of recycling of frying oils to produce biodiesel. The utilization of fuels of agricultural origin in the cycle diesel engines is a good alternative to reduce dependence on importation petroleum, since these fuels are a renewable source of energy. The utilization of biodiesel as biofuel is a contribution to the environment, reducing the qualitative and quantitative form levels of environmental pollution. However, these oils should go through a process of decontamination and decoloration up the stage of chemical conversion which is used clay to lighten the oil. This study aimed to characterize clay of Paraíba to be used in the clearing of frying oil. It was observed through the technique of kinematic viscosity the clays show good results in treatment used vegetable oils.