Reinforcement of EPDM/SmBO3 and EPDM/ATO Composites by Four Polyolefins: Assessment of Branch Content and Crystallinity

From Van Gurp plot, it was found that low-density polyethylene possesses long branches. The larger number of short branches would consume more peroxide and lower the maximum toque (MH) in cure curves. Rheological studies show the complex viscosity of polypropylene (PP) is the highest among four polyolefins. But PP would undergo beta-scission, which would consume peroxide and also lower the MH. Moreover, the acidic Sb-doped SnO2 (ATO) would retard the cure and descend the chemical crosslink points, which would facilitate the motion of ethylene chain and enhance the crystallinity of polyolefin in ethylene-propylene-diene monomer composites.