A Self-healing Power Cable Sheathing Material

During the installation and operation of the power cable, the surface is easily damaged by mechanical damage, shortening its service life, and even causing safety problems such as leakage and power failure. The current damage-repairing method is complicated and requires fault location technology to cooperate, which hinders the repairing effect. Self-healing materials are a class of smart materials that can identify breakages and repair themselves automatically. However, the performance of self-healing materials often does not meet the requirements of power cable materials. In order to meet the special requirements of cable materials for mechanical and electrical performance, specific modifications of self-healing materials are required. In this paper, a novel self-healing material (Poly-CD-PHEA) is polymerized based on the cooperation between host-guest molecules, with Poly-CD as the host molecule, HEMA-Ad as the guest molecule, single-substituted HEA as the reactive monomer. The 2-D NOESY spectra were used to verify the cooperation between Poly-CD and HEMA-Ad. The results showed that there is a significant correlation signal between the protons of the Ad functional group and the protons of $\beta-CD$, indicating that a stable inclusion complex is formed between host and guest. The thermal properties of the material were examined by TGA. The results showed that the Poly-CD-PHEA material can withstand the high temperature of 250 °C, which proves that the thermal stability of the material is good. The self-healing effect of Poly-CD-PHEA was observed by SEM and 3D digital microscope. The results showed that the wound self-healed completely after a period of time, and can complete at least 3 damage-healing processes. The self-healing efficiency of the material is close to 100%. The mechanical properties of the material after self-healing were evaluated by dynamic mechanical analysis (DMA) and tensile test. The results showed that the stress-strain of Poly-CD-PHEA can be restored by more than 80% after self-healing. The volume resistivity test was used to measure the recovery of electrical properties. The results showed that the volume resistivity is basically unchanged before and after self-healing, and both meet the requirements of GB/T 32129-2015. The shape memory effect of the Poly-CD-PHEA material was examined by a shape recovery test, and the results indicated that the material could recover to 98% of the original shape.