Thermal degradation mechanisms of polybenzoxazines

This chapter explains the thermal degradation processes of various Polybenzoxazines and the degradation mechanisms. The structural effects of phenols and amines on the thermal degradation of polybenzoxazines are investigated systematically. The thermal decomposition studies of polybenzoxazines are sometimes difficult because a large number of degradation products are released during the pyrolysis of polybenzoxazines; therefore, model dimmers and oligomers of polybenzoxazines are also examined to have a clear understanding of the thermal degradation mechanisms of polybenzoxazines. Here, the findings related to the thermal degradation processes of polybenzoxazines and the proposed degradation mechanisms for polybenzoxazines are summarized. This chapter explores that among the several techniques used to investigate the thermal characteristics of polymers, thermogravimetric analyzer (TGA), TGA interfaced with Fourier transform infrared spectroscopy (FTIR) or gas chromatography-mass spectrometry (GC-MS), and pyrolysis techniques coupled with FTIR, GC-MS, and MS provide information on thermal degradation products. FTIR combined with TGA or a pyrolysis technique provides information about the type and functionality of the degradation products as a function of time and/or temperature. The use of GC-MS instead of FTIR allows the separation and identification of degradation products. However, condensation of high mass pyrolysates and reactions between the decomposition products during the transport of degradation products from TGA or pyrolyzer system to FTIR or GC-MS are highly probable.