Curing Kinetics of Main-Chain Benzoxazine Polymers Synthesized in Continuous Flow
Zhou Zhou, Qian Si, Li Wan, Shiao‐Wei Kuo, Changlu Zhou, Zhong Xin
Abstract
Main-chain benzoxazine polymers MCBP(BPA-ddm)s were synthesized in continuous flow under various residence times of 5, 10, and 15 min. MCBP(BPA-ddm)s with high molecular weight above 5000–10 000 g mol–1 and high purity over 93% oxazine ring-closed ratio were obtained, which were characterized using Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance spectroscopy, and size exclusion chromatography. In situ FTIR spectroscopy and differential scanning calorimetry were performed to understand the curing reaction and kinetics of MCBP(BPA-ddm)s, suggesting a typical thermally driven self-catalyzed ring-opening polymerization profile with an apparent activation energy of 82–118 kJ mol–1, which follows first-order curing kinetics regardless of the molecular weight.