Effects of ester-terminated glycidyl azide polymer on the thermal stability and decomposition of GAP by TG-DSC-MS-FTIR and VST

Abstract

As a kind of energetic plasticizer, ester-terminated glycidyl azide polymer (GAPE) has a potential for being mixed with energetic binder glycidyl azide polymer (GAP) to enable the system a higher overall energy level. To determine whether the mentioned system can be put into practical use, TG-DSC-MS-FTIR was applied to characterize thermal behaviours of GAP, GAPE and 50/50 GAP/GAPE mixture, and VST was used to decide the compatibility of GAP and GAPE. It turns out that GAPE is compatible with GAP. Decomposition of the mixture can be divided into two steps, rapid decomposition with obvious heat release and self-catalysis decomposition, showing the same tendency with the decomposition of GAP and GAPE. Based on the heating rate of 2, 5, 10 and 15 °C min−1, the kinetics triplets of the three samples’ decomposition were calculated, and the decomposition mechanism was obtained. Results show that the decomposition process was governed by the decomposition of GAPE, which started with the scission of –N3. The critical temperatures of thermal explosion of GAP, GAPE and the mixture were also calculated. Substituting the critical temperature to the reaction rate equation to verify the decomposition process, the dominating role of GAPE in this decomposition of mixture was affirmed. Therefore, GAP/GAPE mixture has a promising future in high-energy propellants/explosives.