Influence of CaCO₃ and Elastomer Incorporation on Impact Properties of PP/Elastomer/CaCO₃ Ternary Composites

Abstract

Influences of elastomer and filler incorporation on impact properties for polypropylene (PP)/elastomer/filler ternary composites were investigated. Calcium carbonate (CaCO₃) particles with a diameter in the range from 120 to 1200 nm were used as filler and polystyrene-block-poly(ethylene-butene)-block-polystyrene triblock copolymer (SEBS) was used as elastomer. In the PP/SEBS/CaCO₃ ternary composite, CaCO₃ particles and SEBS particles were dispersed in the PP matrix separately. In the case that the SEBS volume fraction is below 0.12, the impact strength increased gradually with a decrease of the CaCO₃ particle size. In the case that the SEBS volume fraction is above 0.17, the addition of CaCO₃ particles with a diameter in the range from 120 to 900 nm improved the impact strength. However, the addition of those of 1200 nm never improved the impact strength. The toughening mechanism of the PP/SEBS/CaCO₃ composite was found to be the release of the concentrated strain by the void formation around the CaCO₃ particles.