Study on Self-Healing Technology of Epoxy Resin for Insulator Core Rods

Epoxy resin insulation materials are prone to micro-damage such as scratches and electrical treeing, which can lead to a decline in insulation performance and threaten the safe operation of the entire system. Microcapsule-based self-healing technology is one of the most promising solutions to address the micro-damage issues of epoxy resin. However, research has shown that when the microcapsule doping concentration exceeds 3 wt%, the mechanical strength decreases significantly, while a too low doping concentration affects the healing efficiency. This paper focuses on epoxy resin used in insulator core rods and addresses the contradiction between “low microcapsule introduction” and “high healing efficiency.” This work synthesizes magnetically targeted UV-sensitive microcapsules suitable for self-healing insulator core rods. During the curing process of the epoxy resin, the microcapsules can be directionally guided by a magnetic field to distribute in areas prone to damage, thereby ensuring repair efficiency while reducing the quantity of microcapsules used. The microcapsule shells possess UV-shielding properties, ensuring the stability of the internal repair core material. When damage propagates to the capsules, the core material flows out and cures under UV light, completing the repair of the damage. Additionally, larger-scale self-healing epoxy rod specimens were fabricated, demonstrating excellent self-healing performance against mechanical scratch damage and electrical treeing damage. In comparison, composite materials without microcapsules exhibited a reduction in tensile strength and breakdown strength to 69.06% and 74.77%, respectively, after mechanical damage. Post-repair, the mechanical strength recovery rate reached 91.6%, and the breakdown strength recovery rate achieved 90.4%.