Investigation of deformation mechanism of impact polypropylene

Polypropylene (PP) is one of the most important plastics widely used due to its heat resistance, high stiffness and good processability. However, the application of PP is often limited by its poor impact resistance. In industry, in reactor copolymerization of ethylene-propylene (EP) following PP homo polymerization is an economic and efficient way of toughening PP where the product is impact copolymer of polypropylene (ICP). Yet the mechanism of PP toughening is still elusive which may involve several energy adsorbing mechanism upon deformation. Here we investigate the cavitation formation process upon deformation in ICP using ultra-small angle X-ray scattering (USAXS), where cavity size and shape evolution were monitored upon deformation. Different ICP systems with varying EP fraction and compositions were studied, aiming to correlate the micro-structure developed upon deformation with the molecular attributes of different ICP systems.