Thermal Decomposition Analysis of Spin-Coated Films of Partly Protected Polyvinylphenol with the t -Butoxycarbonyl Group Using Time-Resolved IR

Abstract

Thermal decomposition of spin-coated films of partly protected polyvinylphenol with the t-butoxycalbonyl (tBOC-PVP) group has been investigated by monitoring the intensity of the carbonyl stretching peak of the tBOC group by using temperature-variable time-resolved infrared spectroscopy (TR/IR). The temperature programming method has been used for determining the activation energy (E_a) of the thermal decomposition. We compared the thermal decomposition behavior of tBOC-PVP films with that of the powders and the behavior of a 22% protected tBOC-PVP film with that of a 66% protected tBOC-PVP film. It was found that the E_a of the 22% protected tBOC-PVP film is distinctively higher than the others including the result given from thermogravimetric analysis (TG). In addition, the E_a of the 22% protected tBOC-PVP film increased up to 50 kcal/mol with the decrease of the remaining tBOC group, while the others were constant at 30 kcal/mol. Diglyme, which was used as the solvent in the 22% protected tBOC-PVP film, was residual after the temperature increased above 80 °C, and the reaction velocity of the tBOC group increased in accordance with the generation of the OH group. These results suggest that the OH group, which accelerates the thermal decomposition of tBOC-PVP, is hindered by the residual solvent in the case of the 22% protected tBOC-PVP films.