Studies on multistep thermal decomposition behavior of polytriazole polyethylene oxide-tetrahydrofuran elastomer

Polytriazole polyethylene oxide-tetrahydrofuran (PTPET) is an energetic propellant elastomer that is prepared using glycidyl azide polymer and trifunctional alkynyl-terminated polyethylene oxide-tetrahydrofuran. Its thermal decomposition, determined using thermogravimetic analysis, showed two mass-loss peaks largely related to the decomposition of azide groups and the main chain. Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose methods were deployed to obtain kinetic triplet parameters of PTPET thermal decomposition by the traditional model-free method; the Coats-Redfern approach was used as the model-fitting method. Kinetics analysis indicated that the mechanism of the two-step reactions were the primary-reaction of first order and the power-law phase reaction of the 2/3 order. The first decomposition stage of PTPET had an activation energy (E_a) of 113 to 116 kJ/mol while the second was 196 to 210 kJ/mol. The thermal decomposition of PTPET with different heating rates and mechanisms showed good kinetic compensation effects, the gas products being further studied with TG-FTIR.