Thermal degradation behavior and kinetics of polybenzoxazine based on bisphenol-S and aniline

The thermal degradation behavior of polybenzoxazine based on bisphenol-S/aniline was studied by Fourier transform infrared spectroscopy, thermogravimetry-mass spectrometry, thermogravimetry, and differential thermal analysis. The degradation reaction begins with the detachment of Schiff base, then the scission of aromatic C-S bond, followed by the cleavage of Mannich bridge structure. The scission pathways of the aromatic C-S bond in argon and air are similar, while the degradation pathways of the Mannich bridge structure in both atmospheres are different. The degradation of PBS-a shows two weight loss stages in nitrogen and air, respectively, and the kinetic parameters of the degradation in the first stage were obtained with Flynn-Wall-Ozawa and Coats-Redfern methods. The most probable kinetic mechanism function is a three-dimensional diffusion model in the initial stage in both nitrogen and air. (C) 2011 Elsevier B.V. All rights reserved.