YIELD BEHAVIOR OF POLYPROPYLENE FILLED WITH CACO3 AND MG(OH)2 .1. ZERO INTERFACIAL ADHESION

The composition dependence of tensile yield stress (σyc), and the effects of filler particle shape and surface treatment were investigated for polypropylene (PP) filled with CaCO3 or with Mg(OH)2. Poor adhesion between PP and CaCO3 accounted for a decrease of σyc with increasing σf. In spite of the poor adhesion between PP and Mg(OH)2, σyc either slowly decreased with increasing Vf or remained constant up to Vf = 0.25. Surface treatment of the fillers facilitated better dispersion in PP. On the other hand, σyc was reduced due to the lower thermodynamic work of adhesion (WA). The semiempirical one‐parameter equation proposed by Turczanyi, Pukanszky, and Tüdüs (TPT) was considered plausible and was employed in the study of the effects of matrix‐filler interaction. Copyright © 1990 Society of Plastics Engineers