Studies on the thermal stability of polyurethanes containing pyridine: Thermogravimetric analysis

Recently, pyridine containing polyurethanes (PUPys) are attractive to fabricate supramolecular polymer networks. In this paper, thermogravimetric analysis was used to investigate thermal stability of PUPys quantitatively. The results show that the PUPys have at least two stages of degradation. The thermal stability of PUPys is better under oxygen as compared with nitrogen. PUPys based on hexamethylene diisocyanate tends to have higher onset decomposition temperature, but lower end decomposition temperature as compared with PUPys based on diphenylmethane diisocyanate (MDI). The PUPys with lower pyridine unit content have improved thermal stability at lower temperature range. The addition of rigid hard segment improves the decomposition temperature of pyridine unit, but promotes the weight loss at higher temperature range. Finally, it is proposed that the thermo-oxidative degradation of PUPys might be explained with the association of pyridine ring with hydrogen atom or hydroperoxides.