Thermal degradation of polyurethanes containing lignin studied by TG-FTIR

Abstract

Thermal degradation of polyurethanes (PUs) having various kraft lignin (KL) contents in nitrogen and also in air was studied by simultaneous thermogravimetry and Fourier transform infrared spectroscopy TG-FTIR. Changes of volatile products at various temperatures were analysed. Differences in TG curves and FTIR spectra of PUs and raw materials were observed, suggesting that the thermal degradation mechanism of PUs is different from that of raw materials. The amounts of thermal degradation products having characteristic functional groups changed according to the KL contents in the PUs. Thermal degradation in nitrogen apparently proceeded in one step, while it proceeded in two steps in air. This marked difference suggested that an oxidation reaction occurred during the thermal degradation of PUs in air. © 1998 Society of Chemical Industry