Study on Microcapsules for Self-healing System of Silicone Rubber Insulating Material

The pollution flashover resistance of silicone rubber insulating material is better than that of other insulating materials, but it is prone to aging (e.g., cracks and microcracks) during long-term use, and as a result its service life is limited. Using microcapsule self-healing technology, the extrinsic self-healing polymer materials have the ability to realize the automatic repair of machanical micocracks. The combination of microcapsule self-healing technology and silicone rubbuer insulating material makes it possible to repair microcracks and delay the aging process of silicone rubber. In this study, methyl hydrogen siloxane was selected as the representative of polydimethylsiloxane (PDMS) healing agent, poly (ureaformaldehyde) (PUF) microcapsules were obtained by in-situ polymerization. Furthermore, the influence of emulsifier on the preparation effect of microcapsule was considered. On this basis, the obtained microcapsule was analyzed by optical microscope, scanning electron microscope, Fourier infrared spectroscopy and thermogravimetric analysis. Test results show that poly (ethylene-alt-maleic anhydride) (EMA) + polyvinyl alcohol (PVA) has the best preparation effect of microcapsule. The microcapsule samples with regular shape and intact coating were successfully prepared. Microcapsules had good thermal performance unber 222°C. The analysis results show that microcapsules have the potential to be used in self-healing silicone rubber insulating material system.