Thermal characterization of glycidyl azide polymer (GAP) and GAP-based binders for composite propellants

Differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) were used to investigate the thermal behavior of glycidyl azide polymer (GAP) and GAP-based binders, which are of potential interest for the development of high-performance energetic propellants. The glass transition temperature (T-g) and decomposition temperature (T-d) of pure GAP were found to be -45 and 242 degrees C, respectively. The energy released during decomposition (Delta H-d) was measured as 485 cal/g. The effect of the heating rate on these properties was also investigated. Then, to decrease its T-g, GAP was mixed with the plasticizers dioctiladipate (DOA) and bis-2,2-dinitropropyl acetal formal (BDNPA/F). The thermal characterization results showed that BDNPA/F is a suitable plasticiser for GAP-based propellants. Later, GAP was crosslinked by using the curing agent triisocyanate N-100 and a curing catalyst dibuthyltin dilaurate (DBTDL). The thermal characterization showed that crosslinking increases the T-g and decreases the T-d of GAP. The T-g of cured GAP was decreased to sufficiently low temperatures (-45 degrees C) by using BDNPA/F. The decomposition reaction-rate constants were calculated. It can be concluded that the binder developed by using GAP/N-100/BDNPA/F/DBTDL may meet the requirements of the properties that makes it useful for future propellant formulations.