Interaction Effects of Three Major Crosslinking Byproducts on Space Charge Accumulation in Polyethylene

Abstract

In order to quantitatively analyze the interaction effects of crosslinking byproducts on charge characteristics in crosslinked polyethylene (XLPE), samples are prepared by soaking additive-free untreated polyethylene in three major byproducts, namely acetophenone (A), cumyl alcohol (C), and a-methylstyrene (M), and space charge measurement under relatively low electric fields of 3, 5, 7, and 10 kV/mm is carried out. The results show that the effect of C on space charge accumulation is comparable with that of A per unit byproduct content, and M exhibits the weakest effect. It is related to the different dissociation degrees of byproducts under different electric fields. An exponential fitting formula is proposed to clarify the significant synergistic and the antagonistic effects of the byproducts on charge accumulation. The synergistic effects on charge accumulation is obvious in LDPE-MC (LDPE soaked in the blend of M and C) at 3,7, and 10 kV/mm, but not at 5 kV/mm, and the LDPE-AC (LDPE soaked in the blend of A and C) shows the same rule at 5, 7, and 10 kV/mm, except for 3 kV/mm. The LDPE-AM (LDPE soaked in the blend of A and M) has antagonistic effects on charge accumulation at 5, 7, and 10 kV/mm, and shows a trend from synergistic effects to antagonistic effects at 3 kV/mm. For LDPE-ACM (LDPE soaked in the blend of A, C and M), synergistic effects are dominant at 3, 5 and 7 kV/mm, then antagonistic effects are obvious at 10 kV/mm. The different rule on space charge accumulation may be due to the discrepant charge injection under different electric fields according to the results of charge distribution with individual byproducts.