Synthesis, characterization, thermal properties and flame retardance of novel phenolic resin/silica nanocomposites

Novel phenolic/silica hybrid ceramers were synthesized by the sol-gel process. FTIR and Si-29 NMR were used to characterize the structure of the hybrids. The results revealed that Q(4), Q(3) and T-3 are the major microstructures. That is, network structures were formed. SEM, TEM and Si mapping revealed that the hybrids were nanocomposites. The thermal properties were investigated by thermogravimetric analysis (TGA). The char yields of the hybrids increased with TEOS content. T-d5 (the degradation temperature at 5% weight loss) of the hybrid that contained 20 wt.% TEOS was 290 degreesC. The T-d5 of the hybrid rose to 312 degreesC as the TEOS content was increased to 80 wt.%. TEOS inorganic components enhance the thermal stability of the hybrids. The limiting oxygen index (L.O.I.) and the UL-94 test revealed that the hybrid ceramer possesses excellent flame retardance. (C) 2003 Elsevier Ltd. All rights reserved.