Theoretical study on the reaction mechanism of a new XLPE insulation material without cross‐linking byproducts: An alternative to peroxide cross‐linking

Abstract

AbstractObjectiveDesign a new cross‐linked polyethylene (XLPE) insulation material without cross‐linking by‐products (an alternative to peroxide cross‐linking). Investigate the process of covalent bonds forming and reaction mechanism of four reaction systems.MethodTheoretical calculation of the reaction potential energy information of the eleven reaction channels is used density functional theory at B3LYP/6‐311+G(d,p) level.ResultsThe calculation results show that the epoxy and reactive functional groups between two poly‐ethylene copolymers can react in situ, form covalent bonds, and realize a network XLPE. This reaction process is cross‐linking byproduct‐free. The reactivity of carboxylic acid functional group is stronger among four reaction systems considered.DiscussionThe reaction Gibbs energy barriers of synergistic reaction are lower than that of step by step reaction. The reaction channel of attacking tertiary carbon site CH on epoxy is more kinetically favorable than that of attacking secondary carbon site CH2 on epoxy.ConclusionThe cross‐linking of epoxy and reactive functional groups between two polyethylene copolymers in situ would be beneficial to avoid forming cross‐linking byproducts of peroxide cross‐linking process, which is a promising method for design thermoplastic insulation materials for power cables.