Synthesis and mechanical properties of the epoxy resin composites filled with sol−gel derived ZrO 2 nanoparticles

Highly dispersive ultrafine ZrO2 nanoparticles were obtained by a modified sol-gel process. The ZrO2 nanoparticles showed a mainly tetragonal crystalline structure with an average particles size of 11 nm and a specific surface of 53.68 m2 g−1. The ZrO2/epoxy resin nanocomposites demonstrated significantly increased mechanical properties, compared with the neat epoxy resin. The optimal mechanical properties were achieved when ZrO2 nanoparticle content is around 3 wt%. The char yield of the composites were significantly improved due to the incorporation of nanoparticles and additional crosslinkage between nanoparticles and matrix.