Silica sol nanoparticles hybridized allyl phenolic resins for improving mechanical and thermal performance

In order to improve the mechanical and thermal performance of traditional phenolic resins, nonpolar silica sol nanoparticles with different particle sizes were introduced into allyl phenolic resins with the presence of solvents. A series of allyl phenolic resins with various etherification degrees were designed and synthesized to investigate phase separation phenomenon between sol nanoparticles and allyl phenolic resins. Cured organic-inorganic hybrid samples for performance evaluation were then prepared under the pressure of 1 MPa and pressureless conditions at 250 °C, respectively. SEM observation results reveal that parameters of particle size, etherification degree, and pressure have remarkable influence on phase separation behaviors. Mechanical test and thermal stability evaluation using TGA, muffle furnace and butane torch burning tests prove that both mechanical performance and thermal stability of allyl phenolic resin could be extensively enhanced through the introduction of silica sol nanoparticles. This study provides fundamental understandings about functions and phase separation behaviors of silica sol nanoparticles in the phenolic resin matrix.