Engenharia de Materiais
URI permanente desta comunidadehttps://repositorio.fei.edu.br/handle/FEI/17
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3 resultados
Resultados da Pesquisa
- ABS/HIPS blends obtained from WEEE: Influence of processing conditions and composition(2016) De Souza A.M.C.; Cucchiara M.G.; Ereio A.V.© 2016 Wiley Periodicals, Inc.The recycling of acrylonitrile-butadiene-styrene (ABS) and high-impact polystyrene (HIPS) from postconsumer electronic equipment housing was investigated. A preliminary study of shot size and particle size effects on the mechanical properties of ABS/HIPS (50/50) blends obtained directly via injection molding was conducted. Injection-molded specimens of ABS/HIPS blends, obtained at different compositions with or without previous extrusion, were subjected to mechanical, thermal, and morphological testing. Preliminary studies showed that a smaller particle size resulted in higher tensile and impact strength, regardless of the shot size used during injection molding. ABS/HIPS blends obtained using previous extrusion presented a slight increase in Young's modulus and a decrease in elongation at break and impact strength. The increase in glass-transition temperature related to the Polybutadiene (PB) phases of these blends indicated a possible increase in crosslinking structures during extrusion. In addition, these blends showed a coarse and heterogeneous morphology, suggesting that ABS did not completely mix with HIPS. Compared to processing conditions, the blend composition appeared to have a much stronger effect on the mechanical properties. The results obtained suggest the possibility of obtaining ABS/HIPS blends directly via injection molding as long as small ground particles are used.
- An investigation on recycled PET/PP and recycled PET/PP-EP compatibilized blends: Rheological, morphological, and mechanical properties(2015) De Souza A.M.C.; Caldeira C.B.© 2015 Wiley Periodicals, Inc.The effectiveness of P(E-co-MA-co-GMA) as a compatibilizer for recycled PET/PP and recycled PET/PP-EP (polypropylene (ethylene-propylene) heterophase copolymer) blends was investigated by means of morphological (scanning electron microscopy), rheological (small amplitude oscillatory shear), mechanical (tensile, flexural and impact tests), and thermal (differential scanning calorimetry) properties. Compatibilizer concentration ranged from 1 to 5 wt % with respect to the whole blend. All blends were obtained in a 90/10 composition using a twin screw extruder. Compatibilization effects for PETr/PP-EP were more pronounced due to ethylene segments present in both PP-EP and P(E-co-EA-co-GMA). PETr/PP-EP has shown greater dispersed phase size reduction, a more solid-like complex viscosity behavior and larger storage modulus at low frequencies in relation to PETr/PP blend. For both investigated blends, mechanical properties indicated an improvement in both elongation at break and impact strength with increasing compatibilizer content. PETr/PP-EP blends showed improved performance for the same level of compatibilizer content.
- Investigation on the use of coir fiber as alternative reinforcement in polypropylene(2010) Bettini S.H.P.; Bicudo A.B.L.C.; Augusto I.S.; Antunes L.A.; Morassi P.L.; Condotta R.; Bonse B.C.Polypropylene/coir fiber composites were prepared according to an experimental statistical design, in which the independent variables, coir fiber, and compatibilizer content, were varied. The compatibilizer used was maleic anhydride grafted polypropylene (PP-g-MA). Compatibilizer free composites were also prepared. Composites were processed in a corotating twin-screw extruder and submitted to mechanical and morphological analyses. The effects of the independent variables on the mechanical properties were assessed through tensile strength, elongation at break, flexural modulus, and impact strength. The morphological properties were assessed by scanning electron microscopy (SEM). The results indicated the need for using compatibilizers in the composites due to the incompatibility of PP and coir fiber. The variable with the strongest effect on the properties was coir content, whose increase caused increase in tensile strength, impact strength and elastic modulus, and decrease in elongation at break. The presence of PP-g-MA was fundamental to achieving the aforementioned results. The effect of increasing compatibilizer content was only observed for the elastic modulus. © 2010 Wiley Periodicals, Inc.