The influences of silane coupling agents on the heat and moisture resistance of basalt fibre‐reinforced composites

Abstract

Abstract Basalt fibre composite materials have shown good application prospects in electrical equipment, but their reliability can be affected by damp‐heat ageing. In this work, the interface, mechanical, and electrical properties of basalt fibre composites treated with three coupling agents via damp‐heat ageing were compared. Molecular simulations were conducted to reveal the damp‐heat ageing mechanism of the composites. The results show that γ‐aminopropyl triethoxy silane (KH‐550) and γ‐glycidoxy propyl trimethoxy silane (KH‐560) perform better as coupling agents as they form bonds with the matrix resin, compared with γ‐methacryloxy propyl trimethoxy silane (KH‐570). After the damp‐heat ageing treatment, the hydrolysis of the defects of the amino groups in the interface of the KH‐550‐treated sample can weaken its mechanical properties and insulation properties greatly. The interface layer of the KH‐560‐treated sample is mostly composed of carbon–oxygen single bonds and methylene groups with its interface structure more stable, which endows the sample with better stability of its mechanical and insulating properties. Therefore, KH‐560 is a more suitable coupling agent for processing basalt fibres to be used in electrical equipment.