Convenient preparation of flexible polysulfide rubber chain-bridged polybenzoxazine

Abstract

In this work, a benzoxazine bridged by a flexible polysulfide rubber chain (BLP) was conveniently prepared through the ring-opening addition of thiol-capped liquid polysulfide rubber (LP-3) and bisphenol-A/aniline-based benzoxazine (B-a). The structure and composition of BLP were investigated by nuclear magnetic resonance (NMR) and Fourier transform infrared (FT-IR) spectra, and the structure and properties of polymerized BLP (PBLP) were characterized by FT-IR, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and thermogravimetric analysis (TGA). BLP was a highly viscous fluid at room temperature with a low curing temperature. After curing, most of the polysulfide chains were incorporated into the crosslinked PBLP through covalent bond linkages. PBLP presented excellent flexibility, outstanding thermal stability, and an extremely high char yield. The glass transition temperature (Tg) of PBLP was 80 °C, the 5% weight-loss temperature (T5%) was 270 °C, and the char yield at 800 °C was 33%. Benzoxazine bridged by a flexible polysulfide rubber chain (BLP) was conveniently prepared through the ring-opening addition of thiol-capped liquid polysulfide rubber (LP-3) and bisphenol-A/aniline-based benzoxazine (B-a). BLP was a highly viscous fluid at room temperature with a low curing temperature. After curing, the polymerized BLP (PBLP) presented excellent flexibility, outstanding thermal stability, and an extremely high char yield.