Pyrolysis behavior of poly[(n-propylamino/methylamino)borazine]

A processable poly[(n-propylamino/methylamino)borazine] (PPAB) has been pyrolyzed in Ar to study its thermal decomposition behavior. The structural evolution and chemical composition change during pyrolysis were characterized by chemical analysis, thermal gravimetry–mass spectrometry (TG–MS), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results indicated that the polymer-to-ceramic transition of PPAB involved two steps. Below 400 °C, the gas species were mainly methane and methylamine, while from 400 to 900 °C those were methane and n-propylamine. The PPAB displayed a ceramic yield of 52 wt% at 1000 °C and the pyrolyzed product was amorphous boron nitride (BN) with a small quantity of carbon impurity, in presence as CC and CN bonds. Moreover, for the pyrolyzed product, further heat treatment resulted in the occurrence of a transformation from amorphous to turbostratic.