STRUCTURE AND PROPERTY OF RADIATION CROSSLINKED LOPE-EPDM BLENDS

The regularity of radiation crosslinking and the radiation effect on thestructure and property of LDPE (low density polyethylene)-EPDM (copolymerof ethylene-propylene) blends are reported in this paper. The results show that radiation crosslinking effect on LDPE/EPDM blendsis either similar to pure LDPE or EPDM, depending upon which one is the main component in the blends. When the content of LDPE is higher than that ofEPDM, crosslinking of the blend is close to pure LDPE. The relationship betweenS+S~(1/2) and 1/R does not comply with Charlesby-Pinner's equation. While forblends rich in EPDM, a linear relationship is observed at high doses. The higherthe content of EPDM in the blend, the easier is the blend to be crosslinkedbecause of the presence of unsaturated bond in EPDM. The crystalline extent and density of the blend increases with increasingLDPE content in the blends. No obvious change of crystalline extent is observedin the dose range used. There is a close relationship between mechanical property and composition ofthe blends. The tensile strength (T_s) increases with increase in LDPE content,whereas the elongation (E%) shows a reverse effect. The effect of radiation doseon T_s is insignificant. However the elongation (E%) is seriousely affected.