Optimizing Mechanical Performance in Woven Basalt Fibers/Epoxy Composites: Using Silane Coupling Agents to Modify Epoxy Resin for Fiber-Matrix Interface

Abstract

This study reveals that incorporating silane-coupling agents such as KH560, KH590, KH570, and KH550 into the resin matrix can improve the epoxy mechanical performance as well as the interfacial interaction between basalt fibers and modified epoxy. The increasing silane contents slightly increased thermal stability and char yields. The study also found that amino-silane coupling agents, particularly KH550, demonstrated better thermal stability enhancement. Pure epoxy had a Tg of 91.4 °C, while epoxy had modified with 9wt% KH550 exhibited the highest Tg of 98.7 °C. For instance, at 6 wt% concentration of KH560, KH590, KH570, and KH550, the flexural strength of the epoxy matrix increased by 69.4%, 57.6%, 83.4%, and 84.7%, respectively. When the content of KH590, KH570, and KH550 is 9 wt%, the tensile increases by 77.6, 49.0, and 79.6%, respectively. The W-BFs/epoxy composite flexural strength enhanced by 65.3, 81.5, and 74.5%, respectively. The compatibilizing agent would react with the silicon hydroxyl groups on the surface of the basalt fibers, as well as with the epoxide in the resin. This would create a Si-O-Si new bond, which would make the connection between the modified epoxy and the basalt fibers stronger. This process is favored for its cost-effectiveness and user-friendly operation.

Graphical Abstract