Synthesis of Borosiloxane/Polybenzoxazine Hybrids as Highly Efficient and Environmentally Friendly Flame Retardant Materials

A series of novel borosiloxane/polybenzoxazine hybrids were synthesized through the copolymerization of 3,3'-phenylmethanebis(3,4-dihydro-2H-1,3-benzoxazine) and phenolfunctionalized borosiloxane (BSi-OH) oligomer. The structures were characterized using nuclear magnetic resonance and fourier transform infrared. The thermal and flame retardant properties of hybrids were investigated by dynamic mechanical analysis, thermogravimetric analysis, and oxygen index instrument. The results showed that the addition of BSi-OH oligomer is not only highly efficient in environmentally friendly flame retardancy of polybenzoxazine, but also enhances its thermal property. Only 25 wt % content of BSi-OH oligomer was able to increase the glass transition temperature, 5% weight loss temperature (T-d5), 10% weight loss temperature (T-d10), and limited oxygen index (LOI) value from original 211 degrees C, 374 degrees C, 395 degrees C, and 29.5 degrees C to 244 degrees C, 408 degrees C, 448 degrees C, and 40.1, respectively. This work provides a facile and useful method for the preparation of new polybenzoxazines possessing highly efficient and environmentally friendly flame retardance as well as heat resistance. (C) 2017 Wiley Periodicals, Inc.