EFFECT OF ELECTRON BEAM IRRADIATION ON THE STRUCTURE–PROPERTY RELATIONSHIP OF ETHYLENE OCTENE COPOLYMER AND POLYDIMETHYL SILOXANE RUBBER BLENDS

Abstract

ABSTRACT The effects of electron beam irradiation on the structure–property relationship of blends can be studied based on ethylene octene copolymer (EOC) and polydimethyl siloxane (PDMS) rubber at three different blend ratios prepared with a melt mixing technique. Irradiation with 2.5 MeV electron beam accelerating energy, over a radiation dose varying from 25 to 150 kGy, causes cross-linking in both the EOC and the PDMS phases. However, cross-linking of the EOC phase without affecting the crystallinity of the EOC polymer leads to tremendous improvement in the physicomechanical properties, including the tensile strength, which improves by nearly 35% for 70:30 EOC:PDMS blends. Morphology of the blends before and after irradiation can be analyzed by scanning electron microscopy and atomic force microscopy and correlated with the physicomechanical properties. The physicomechanical properties of the individual polymer components after irradiation show that radiation cross-linking is more effective for PDMS rubber than it is for EOC. However, at higher radiation doses, chain scissions are possible in both EOC and PDMS rubber, which affect the physicomechanical properties. Through blending and subsequent radiation cross-linking, the maximum degradation temperature of EOC can be increased from 488.6 to 512.8 °C.