SC–CO2-assisted rubber dispersion and dynamic vulcanization in blending of PP/EPDM thermoplastic olefin

Abstract

Supercritical CO2 (SC–CO2), as a green medium, was induced in the traditional way of preparing polypropylene/ethylene–propylene–diene terpolymer (EPDM) thermoplastic olefin (TPO) by dynamic vulcanization using a twin-screw extruder. The morphology observation suggested that the SC–CO2 not only promoted the rubber dispersion, but also facilitated the rubber dynamic vulcanization; therefore, the crosslinked EPDM particles were more densely distributed in the TPOs prepared with SC–CO2, and existed as a stronger viscoelastic phase restricting the mobility of polymer chains, increasing the complex viscosity and storage modulus and promoting the mechanical properties.