Crystallization Characteristics and Electrical Properties of UV Crosslinked LLDPE/EPDM Blends

Ultraviolet (UV) irradiated cross-linking technology has the advantages of high efficiency and low power consumption. In order to employ the UV cross-linking technology in manufacturing ethylene propylene diene monomer (EPDM) rubber cable insulation layer, linear low density polyethylene (LLDPE) was melt-blended into EPDM to improve its mechanical property and UV cross-linking efficiency. LLDPE/EPDM composites with different contents of LLDPE were prepared. The crystallization characteristics and electrical properties of UV crosslinked LLDPE/EPDM blends were investigated. Compared with the unreinforced EPDM, the mechanical properties of LLDPE/EPDM composites were significantly higher. The results of SEM show that EPDM inhibits the crystallization of LLDPE and make the crystalline grains smaller. With the increase of LLDPE addition, the isolated LLDPE crystal structure gradually changes to a continuous crystal form, and its AC breakdown strength generally increases. The results of DSC and XRD show that the blending of EPDM and LLDPE do not produce a new crystal form but there were two aggregation states of the same crystal form in the LLDPE/EPDM composites.