The importance of morphology on electrical strength of LDPE/XLPEinsulations

摘要

An attempt was made to change the morphology of LDPE/XLPE(low-density polyethylene/cross-linked polyethylene) by several methods,and the impulse breakdown strength IBDS of the samples was investigated.It was found that the thermal procedure which effectively changed themorphology of polypropylene did not alter the morphology of LDPE/XLPEsignificantly; consequently, IBDS was not influenced in this way.Monoaxial and biaxial mechanical stretches of XLPE resulted in a certainalteration of the morphologies of these samples. IBDS was enhancedduring these stretches. Removal of the lower-molecular portion from theLDPE matrix produced an increase in density and enhanced IBDS for theresultant LDPE. This suggests that this removal would give a compactlyarranged amorphous region for LDPE, and that the amorphous part in LDPEmay play the predominant role in electrical breakdown phenomena