Electrical and Hydrolysis-resistance Properties of Silicone-Modified Resin/Microsphere Syntactic Foam for Composite Cross-arms Insulation Application

Herein, a type of syntactic foam, consisting of silicone-modified resin and hollow polymer microspheres, is developed and tested for the application of a composite cross-arm. The physical properties, electrical properties, and hydrolysis-resistance are tested and analyzed. Suitable microspheres can reduce the density of the syntactic foam to 46.63% of the resin. The dielectric strength of the syntactic foam decreases from 37.9 to 26.1 kV/mm with increasing microsphere content, which is still much higher than the operational requirement of 3 kV/mm. The water-absorption rate (<0.36% after 720 h) and leakage current (<24.17 μA after boiling for 300 h) show that the syntactic foams have excellent penetration resistance and hydrolysis-resistance. In summary, the syntactic foam can be used as the internal insulation material for composite cross-arms and applied to the electrical insulation field.