Effect of Modified Calcium Carbonate on Mechanical Properties of Polypropylene/Thermoplastic Elastomers

Abstract

Polypropylene (PP) /thermoplastic elastomer (TPE) blend samples filled with calcium carbonate (CaCO₃) were prepared. These had been modified with mono-alkyl phosphate esters. They were tested to improve modulus and impact properties of filled composites. The relations between impact properties of composites and levels of TPE content and length of alkyl chain of modifiers have been investigated. Styrene/butadiene block copolymer (SBS) was found to be the best for the improvement of impact strength. How length of alkyl chain depended on impact strength and on void fraction incorporated by drawing at filler/polymer interface of PP/SBS composites was studied. Additions of modified CaCO₃ to PP filled with 2.5-5wt% of SBS have produced major improvements not only in impact strength but also in modulus of filled composites over results with PP base resin.