EFFECT OF TITANATE COUPLING AGENT ON THE MECHANICAL PROPERTIES OF CALCIUM CARBONATE FILLED POLYPROPYLENE

Abstract

Composites of polypropylene filled with untreated and treated calcium carbonate (CaCO₃) have been prepared. The surface modification of calcium carbonate was done by using titanate coupling agent. The effect of this treatment on the interfacial adhesion and the dispersion of filler particles in the polymeric matrix was evaluated by performing mechanical, thermal and optical analysis. The results obtained indicate that the incorporation of non-treated CaCO₃ decreases in general the mechanical properties (except the modulus) of the composites. However, the use of treated calcium carbonate increases the amount of filler that can be incorporated in the polymeric matrix. Mechanical properties such as tensile and flexural stresses, elongation at break, modulus and impact strength are also improved. Differential thermal analyses indicate the existence of aninterface between the polymeric matrix and the treated filler particles. Micrographic analyses confirm the efficiency of surface treatment of the filler on its dispersion.