The trapping characteristic of low density polyethylene in the presence of crosslinking by-products

摘要

The by-products of dicumyl peroxide (DCP) from the crosslinking process such as acetophenone, cumyl alcohol and ?-methylstyrene are said to be the sources of space charge formation in XLPE cable due to deep traps in the chemicals. However, by using space-charge experimental approach, it appeared that these chemicals show a different trapping nature. This paper is intended to present this approach. Additive-free low density polyethylene (LDPE) was used as base material so that each chemical can be tested individually. Space charge measurement was done using the pulse electroacoustic (PEA) method. All results were compared to the clean LDPE to identify the contribution of the chemicals to the trapping characteristic. The data collected supported that although the chemicals introduce charge in the insulator, the charge decay is extremely fast especially in the presence of ?-methylstyrene. It is believed that the chemicals modify the trapping characteristic of LDPE so that more shallow traps are formed in the insulator.