Study on the Effect of Curing Shrinkage Marks on Electrical Properties of Epoxy Composites

摘要

Curing shrinkage mark is typical curing defect which is easy to occur in the preparation of epoxy composites. In order to study the effects of this kind curing defect on the electrical properties of epoxy composites, epoxy resin samples with curing shrinkage marks on the surface were prepared. The effects of curing defects on the electrical properties of the samples were analyzed by measuring the flashover voltage, withstand voltage time, volume resistivity and surface resistivity of the samples before and after surface flashover. The research results show that the effects of curing shrinkage marks on the flashover voltages are not obvious, but they have a great influence on the withstand voltage time of the samples. When the shrinkage mark and the electrode become 90°, the withstand voltage time of the sample is the shortest. The volume resistivity and surface resistivity of the samples will decrease because of surface flashover. Before and after flashover, the volume resistivity and surface resistivity of samples with curing shrinkage marks are smaller than those without curing defects. The results show that the curing shrinkage marks will lead to the decline of the overall electrical properties of epoxy composites.