Preparation and Characterization of Ethylene-Octene Copolymer/Modified Nanosilica Composites by Radiation Processing

Abstract

Modified nanosilica (M-SiO2) by coupling agent (KH570, γ-MPS) with C=C bond reinforced ethylene-octene copolymer (POE) nanocomposites were prepared by melt blend, and then irradiated by γ-rays under nitrogen. The results of the crosslinking degree measurement revealed that the crosslinking degree of POE/modified nanosilica composites depended on the modified nanosilica particle size, content and the absorbed dose. Compared with the gel fraction of neat POE which is about 1.8%, the gel fraction of POE/15-M-SiO2-20 improves significantly to 34.2% at very low dose of 40kGy. Moreover, when nanosilica particle size become smaller, the sensitization effect is more obvious at a constant loading level. In comparison to the neat POE with a tensile strength of 22.6MPa, the tensile strength of POE/15-M-SiO2-10 nanocomposites increased to 29.1MPa with an absorbed dose of 100kGy, whereas their elongation at break were gradually reduced with an increasing absorbed dose. The improvement of gel content led to the enhancement of thermal deformation performance of POE/M-SiO2 nanocomposites attributed to the formation of crosslinked network between POE and modified nanosilica by radiation.