Theoretical study on the hydrogen addition reactions to bismaleimide in the ultra-violet radiation cross-linking process of polyethylene

Theoretical investigation on the multiple-channel addition reactions of hydrogen in polyethylene to bismaleimide in the Ultra-violet (UV) radiation cross-linking process is accomplished by density functional theory. Their energetic information of the nineteen reaction channels at B3LYP/6-311 + G(d,p) level is obtained. Two types of electrophilic addition reaction, one is the 4-position hydrogen in 4-methylheptane to C of C=C groups in bismaleimide and the other one is the 4-position hydrogen in 4-methylheptane to O of C=O groups in bismaleimide, are identified. The effects of introducing the heteroatom O and/or the benzene ring among both ends of the two maleimide rings have been evaluated. The results show that the addition reaction potential barrier height to O in C=O groups is lower than that of the C in C=C groups in the conjugative bismaleimide system.The founding of the addition reaction channel to O in C=O groups could clear further the mechanism of grafting bismaleimide to polyethylene.