Engenharia de Materiais
URI permanente desta comunidadehttps://repositorio.fei.edu.br/handle/FEI/17
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3 resultados
Resultados da Pesquisa
- Linear viscoelastic behavior of compatibilized PMMA/PP blends(2013) De Souza A.M.C.; Calvao P.S.; Demarquette N.R.In this work, the morphology and linear viscoelastic behavior of PMMA/PP blends to which a graft copolymer PP-g-PMMA has been added was studied. The copolymer concentration varied from 1 to 10 wt % relative to the dispersed phase concentration. The rheological data were used to infer the interfacial tension between the blended components. It was observed that PP-g-PMMA was effective as a compatibilizer for PMMA/PP blends. For PP-g-PMMA concentration added below the critical concentration of interface saturation, two rheological behaviors were observed depending on the blend concentration: for 70/30 blend, the storage modulus, at low frequencies, increased as compared to the one of the unmodified blend; for 90/10 blend, it decreased. For 90/10 blend, the relaxation spectrum presented an interfacial relaxation time related to the presence of the compatibilizer (τβ). For PP-g-PMMA concentrations added above the critical concentration of interface saturation, the storage modulus of all blends increased as compared with the one of the unmodified blend. Copyright © 2012 Wiley Periodicals, Inc.
- 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.