Simultaneous temperature and species measurements of the glycidyl azide polymer (GAP) propellant during laser-induced decomposition

Abstract

Simultaneous temperature and species measurements were performed to experimentally investigate thermal decomposition of cured Glycidyl Azide Polymer (GAP). Experiments were conducted at atmospheric pressure in argon with heat fluxes of 50, 100, and 200 W/cm 2 delivered by CO 2 laser. A micro-probe/triple quadrupole mass spectrometer system was used to analyze species products, and thermocouples were used to measure temperature. The burning behavior was monitored by a high-magnification video system. The following major species, in descending order of abundance, were detected: N 2, HCN, CO, CH 2O, NH 3, CH 3CHO, CH 2CHCHNH, CH 3CHNH, H 2O, CH 4, and C 2H 4. The mole fraction of hydrocarbons was about 0.02, while the mole fraction of imines was 0.09. The decomposition of GAP appeared to be dominated by the condensed phase chemistry and few reactions occurred in the gas phase. A significant amount of fine solid powder was observed in the gas phase, which was believed to be imines. It was found that the species and temperature were insensitive to the heat flux level. The mole fractions of the observed species at a heat flux 100 W/cm 2 were almost the same as those at a heat flux of 200 W/cm 2, and the surface temperature was approximately 1050 K at both heat fluxes.