Thermally Induced Healing of Electrically Insulating Ethylene–Octene Copolymers

We report on electrical insulating materials that not only have sufficient mechanical toughness to survive use conditions but also possess the ability to undergo thermally induced self-repair when damaged. By controlling the cross-link density, a modified ethylene–octene copolymer (EOC) is able to retain its self-healing abilities while also being used at temperatures greater than the original, unmodified polymer. Specifically, an EOC cross-linked with 0.25 wt % dicumyl peroxide affords a material ability to recover 61% of its critical fracture energya value similar to thermoplastic EOC. Furthermore, as shown by dielectric spectroscopy, the cross-linked EOC retains good electrically insulating properties.