Preparation and performance improvement of a dual‐component microcapsule self‐healing system for silicone rubber insulating material

Abstract

A key factor limiting the development of silicone rubber insulating materials is their short service life in harsh operating environments. The establishment of a self‐healing system is desired to improve the long‐term operational performance of silicone rubber and effectively extend its service life. In this study, poly(urea‐formaldehyde) microcapsules containing polydimethylsiloxane healing agents are prepared and a dual‐component microcapsule self‐healing system for silicone rubber material is established and optimised. In addition, the key factors affecting the self‐healing performance (such as microcapsule size, rupture rate, and microcapsule doping amount) are investigated. It is found that when SYLGARDTM 184 is used as the healing agent and matrix, with a 4:6 (A:B) doping ratio of dual‐component microcapsules and 20 phr doping amount, the self‐healing efficiency is approximately 51%. Furthermore, increasing the microcapsule rupture rate and the interface strength between the healing agent and the matrix can effectively improve the self‐healing performance. The relationships between key factors and self‐healing performance are theoretically revealed. Based on the relationships, the microcapsule self‐healing system can be appropriately designed. The results of this paper can provide a reference for the development of long‐life silicone rubber insulating materials.