Self-healing properties of composites made of multi-monomer grafted polyethylene materials

To inhibit and repair the damage to cable insulation caused by the formation of water tree structure by micro water droplets at insulation defects in low-density polyethylene (LDPE) materials under the action of an AC electric field. In this paper, using low-density polyethylene as the matrix, we investigate the effects of graft modification and nano-doping on the growth of water trees in LDPE materials and design LDPE composite insulating materials with different components. Accelerated water tree aging experiments were carried out using the water needle electrode method to analyze the repair ability of grafted monomers on the damaged area of the water tree. Through the observation of OM, SEM, and FDS of the materials before and after aging, it is shown that the LDPE composite insulating material doped with a small amount of nano-SiO 2 has a good self-repairing property of water tree. By testing the insulation and mechanical properties of the aged LDPE composite insulation material doped with a small amount of nano-SiO 2 , it was found that both could be restored to about 90 % of the pure sample, indicating that the self-healing performance of the composite material is very excellent. The research in this paper not only improves the online service life of the cable but also provides a new idea for repairing LDPE cable insulation materials, which has good research prospects in practical applications.