Brittle-ductile transition in polypropylene filled with glass beads

The effect of surface treatment of glass beads with a silane coupling agent and the filler content on the notched Izod impact properties of the filled polypropylene (PP) composites has been investigated. It was found that the impact fracture energy of the composites, E-IC, increased with increasing the volume fraction of glass beads, phi(f); the influence of surface treatm ent of glass beads on E-IC was insignificant; the brittle-ductile transitio n (BDT) phenomenon occurred when phi(f) was about 10%. A modified percolati on model for BDT in thermoplastic-rigid particle blends is proposed under t he basis of predecessors' work. The results show that the BDT of the compos ites in impact can be considered as a percolation process. (C) 1999 Elsevie r Science Ltd. All rights reserved.