Effect of EPDM Content on Melt Flow, Microstructures and Fracture Behavior of Dynamically Vulcanized PP/EPDM Blends

Abstract

Polypropylene (PP)/Ethylene‐propylene‐diene terpolymer (EPDM) blends were dynamically vulcanized with dicumyl peroxide (DCP), using a two‐step method of even dispersion of DCP in EPDM at first and then cross‐linking at elevated temperature. The results showed that though both chain scission and cross‐linking occurred, the cross‐linking reaction predominated in this process and the number of EPDM particles was increased, accompanied with a reduction in particle size and uniform dispersion. Differential scanning calorimetry (DSC) results indicated the existence of PP/EPDM graft copolymer. The essential work of fracture (EWF) results showed that both the specific essential work of fracture (w e ) and the specific plastic work (w p ) increased with increasing EPDM content, the fracture toughness and plastic energy consumption (βw p ) could be improved simultaneously and the ratio of w e and βw p could be controlled by adjusting EPDM and DCP content.