Thermal degradation of PBO fiber investigated by TGA-DTA/FTIR and Py-GC/MS

PBO fiber is so far the most high-temperature resistant polymer fiber. In this paper, the thermal degradation of PBO fiber under inert gas and air were studied using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and thermogravinietric analysis coupled with Fourier transform infrared spectroscopy (TGA-DTA/FTTR). From room temperature to 1000 degrees C, the residue rate of PBO fiber was 76.5% in nitrogen. The results of Py-GC/MS showed that the repeating unit of molecular chain was the most pyrolysis fragment, and CO2 and benzene also kept great yields in all pyrolysates. After 650 degrees C, the volatiles, including HCN, NH3, NO2, NO, CO, CO2, H2O and aromatic compositions can be found by TGA-DTA/FTIR in nitrogen. But in air, PBO almost lost mass all when the temperature reached 1000 degrees C. Only several little molecular volatiles, such as CO2, NO2, HCN, H2O, etc were searched during degradation by the means of TGA-DTA/FTIF, especially after 650 degrees C, thermal degradation happened intensively and CO2 was produced importantly.