Electrical Strength Tests of a Self-healable Copolymer Based on Ethylene and Anisylpropylene

The paper deals with a novel self-healable polymer synthesized by scandium-catalyzed copolymerization of ethylene and anisylpropylenes. The electrical strength of the material was characterized according to the standard IEC 60243 and was carried out with an AC voltage increase of 1 kV/s at the industrial frequency of 50 Hz five consecutive times. It was found that electrical breakdown caused minor cracks and more significant light gaps between darker regions, which indicated a shrinkage of the material. Moreover, it was also noticed that the increased electric field intensity caused such an energy load on the material, which led to a fast ignition of material in the region of contact with the test electrodes. At first, discharge activity was initiated, causing significant heating of the material, and then, the burning occurred at the electric field strength varied from 32 to 43 kV/mm. These values proved that the tested self-healing material is relatively stable in an oxidizing atmosphere. It was further found that the forming conductive channel is actively treated with "healing plugs" continuously formed during the electrical breakdown tests. The results so far allow us to consider self-healable copolymers based on ethylene and anisylpropylenes as a perspective group of insulation materials.