Effect of Dispersant and Morphologies on Mechanical Properties of Polypropylene Composites

Abstract

Relation between morphology and mechanical properties of Polypropylene (PP)/elastomer/filler ternary composites were investigated. Polystyrene-block-poly (ethylene-butene)-block-polystyrene triblock copolymer (SEBS) or carboxylated SEBS (C-SEBS) was used as elastomer and calcium carbonate (CaCO3) having mean size about 160nm was used as filler.In the PP/SEBS/CaCO3 ternary composite, CaCO3 particles and SEBS particles were dispersed in the PP matrix separately. In the PP/C-SEBS/CaCO3 ternary composites, CaCO3 particles were encapsulated in C-SEBS and core-shell particles were formed at lower CaCO3 concentration. However, at higher CaCO3 concentration, some CaCO3 particles were dispersed in PP matrix.Modulus of the PP/SEBS/CaCO3 composites was in agreement with expanded Lewis-Nielsen's equation. On the otherhand, the modulus of the PP/C-SEBS/CaCO3 composites was in agreement with elastomer enforced Nielsen's equation.Tensile yield stress of the PP/SEBS/CaCO3 composites was in agreement with Pkanzsky's equation. However, the tensile yield stress that of the PP/C-SEBS/CaCO3 is higher than the Pkanzsky's equation, because a part of CaCO3 particles was included into the C-SEBS particles.In the PP/SEBS/CaCO3 composite, the impact strength increased with the amount of incorporated CaCO3 particles. Whereas, in the PP/C-SEBS/CaCO3 composite, the impact strength increased dependent upon the amount of CaCO3 particles dispersed in PP matrix.