Space charge distribution in low-density polyethylene with blocking layer

Charge carriers injected from the electrode and charge carriers generated in the bulk contribute space charge in low density polyethylene (LDPE). However, it is sometimes difficult to separate their contributions. In this paper, a fluorinated ethylene propylene copolymer (FEP) film was used as a blocking layer. It was effective to separate injected carriers and bulk-generated carriers. The electrode materials used were aluminum and semiconductive (SC) polymer. Charge carriers were mainly injected from the SC electrode into a specimen of Al/LDPE/SC and they formed homo space charge. A blocking FEP film suppressed the carrier injection and it gave information about the behavior of bulk-generated carriers. From these results, we discussed the contributions of injected carriers and bulk carriers to space charge in LDPE.