Abstract
The preparation of the phenolic resin/silica hybrid organic-inorganic nanocomposite is via sol-gel process. The coupling agent was used to improve the interface between organic and inorganic phase. Effects of nanocomposite structure on the physical and chemical properties were discussed.The reaction of coupling agent and resin forms covalent bonds. The structure of the covalent bonds was identified by Fourier-transform infrared (FT-IR) spectroscope. The silica network was characterized by solid-state 29Si nuclear magnetic resonance (29Si solid-state NMR). Results revealed that Q4 (tetra-substituted siloxane bond) and T3 (tri-substituted siloxane bond) are the major microstructures. The size of silica particle in the phenolic resin was characterized by scanning electron microscope (SEM). The particle size of inorganic silica in the modified-system is less than 100 nm. The hybrid nanocomposites exhibits excellent transparence.Thermal properties and mechanical properties show significant difference between the conventional composite and nanocomposite. The modified hybrid composite exhibits promising thermal properties. The 5% weight loss temperature increased from 281℃ to 350℃. The flexural strength increased by 6~30%. The L.O.I. of the nanocomposite can reach 35 and the U.L. value is 94V-0. Hence, the materials possess excellent flame-retardant properties.