Graft reaction of styrene-acrylonitrile onto metallocene-based polyethylene-octene elastomer and its toughening effect on SAN

摘要

Metallocene-Based Polyethylene-Octene-graft-styrene/acrylonitrile (POE-g-SAN) was synthesized by grafting styrene (St) and acrylonitrile (An) onto POE elastomer. The reaction. was carried out in toluene using benzoyl Peroxide as initiator at 75 degrees C. Various weight ratios of monomers, weight ratios of POE to monomers, initiator concentration, reactant concentration, and reaction time were studied to investigate their effects on the graft copolymerization. The graft copolymer were identified and characterized by FT/IR spectroscopy and H-1 NMR. The chain structure of the graft copolymer was investigated by glass transition temperature using differential scanning calorimetry (DSC). The results showed that St/An was grafted on the POE chains, and the graft branches effected the crystallization of POE chains and made the melt temperature and the fusion heat be lower. In addition, according to the research on mechanical properties of the SAN/POE-g-SAN blend, a remarkable toughening effect of POE-g-SAN on SAN resin was found. By means of scanning electron microscopy (SEM), the toughening mechanism is proposed to be crazing initiation from rubber particles and shear deformation of SAN matrix.