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

Abstract

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 (Tg) and decom- position temperature (Td) of pure GAP were found to be 245 and 242°C, respectively. The energy released during decomposition (DHd) was measured as 485 cal/g. The effect of the heating rate on these properties was also investigated. Then, to decrease its Tg, 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 Tg and decreases the Td of GAP. The Tg of cured GAP was decreased to sufficiently low temperatures (245°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. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 538 -546, 2000