Transparent self-extinguishing silica-epoxy nanocomposites based on Novolac resin

Sol-gel chemistry was used to synthesize transparent fire-resistant silica-epoxy nanocomposites based on Novolac resin. Unlike conventional systems, this approach forms well-dispersed amorphous silica nanoparticles, maintaining high transparency (~80% transmittance). A small amount of phosphorus-based additive allows to achieve self-extinguishing without any dripping and achieve UL94-V0 rating during vertical burning tests. The nanocomposites also show significantly reduced heat release rate, demonstrating improved fire safety. Compared to traditional hybrid systems based on bisphenol A diglycidyl ether, this method avoids particle crystallization and opacity at higher filler loadings. Overall, it offers a scalable and efficient strategy for developing multifunctional high-performance materials for advanced applications.