Polyurethane thermal effects studied using two-dimensional correlation infrared spectroscopy

摘要

Two-dimensional (2D) correlation infrared spectroscopy was used to investigate the thermal effects of polyurethane. Five structure transitions were observed at around 65 ℃, 150 ℃, 190 ℃, 235 ℃ and 265 ℃ using moving windows two-dimensional correlation spectroscopy (MW2D). 65 ℃ and 150 ℃ were the glass transition temperature of hard segments (HS) and viscous flow temperature, respectively. 190 ℃, 235 ℃ and 265 ℃ were three thermal degradation temperatures of HS. It was proved that MW2D was sensitive to the polymer structure transitions. The overlapped NH and C=O absorbance bands were identified and analyzed by generalized two-dimensional correlation infrared spectroscopy (2DCOS). The evolvements of the different types of NH and C=O during the transitions were obtained. The results showed 2DCOS could improve the analytical ability of in-situ FITR. Both the two 2D correlation methods are helpful for the polymer degradation mechanism studies.