Ultraviolet light irradiated high‐efficiency crosslinking and insulating properties of LLDPE / EPDM blends

Ultraviolet light (UV) irradiation crosslinked linear low‐density polyethylene (LLDPE)/ethylene propylene diene monomer (EPDM) composites with different blending ratios were prepared using benzophenone (BP) as photoinitiator and triallyl isocyanurate (TAIC) as crosslinking agent. The irradiation time was determined, the effects of rubber‐plastic ratio on the crystallization behaviors, mechanical properties, crosslinking properties and electrical properties of LLDPE/EPDM composites were investigated. The results show that with the increase of EPDM content, the crystalline structure of LLDPE/EPDM composite become looser and the crystallinity decreased. The blending of EPDM and LLDPE results in two different aggregation states of the same crystalline form. With the increase of LLDPE content, the crosslinking efficiency, tensile strength, and energy storage modulus show a significant upward trend. When two polymers simultaneously exist in the material, if the difference between the contents of two polymers is large, the breakdown strength of the composite is relatively lower. The relaxation polarization of LLDPE/EPDM at low frequencies increases with the content of EPDM, thus leading to the increase of loss factor at low frequencies. A novel UV crosslinked modified EPDM insulating material with high production efficiency and improved insulation performances has been developed for use as an insulating layer for flexible power cables.