Kinetic of Deep High-Temperature Decomposition of Model and Commercial AP-Based Composite Solid Propellants

Abstract

The kinetics of fast high-temperature decomposition is quantitatively studied for a number of model and commercial heterogeneous polymer–ammonium perchlorate systems using original nonisothermal kinetics methods employing DTA, TGA and DSC instruments. Maximum temperatures corresponding to the determined kinetic parameters reach 400–450^ˆC, which are quite close to those in the solid propellant reaction zone near the burning surface. Data presented in this chapter can be used for the analysis of combustion patterns and mechanisms of solid propellants, while the results of earlier works on the kinetics of low-temperature decomposition are only useful for assessing the stabilities of the propellants during long-term storage. This is also confirmed by comparing the corresponding kinetic constants. For example, the activation energies for the low-temperature decomposition of the majority of the studied solid propellants are close to 120 kJ mol^-1*, which corresponds to the decomposition of AP. The activation energy of the second stage of the high-temperature decomposition of almost all AP–polymer mixtures is twice as high. An explanation of this quite general effect is presented. An excellent correlation between the obtained kinetic constants of high-temperature reactions and the ignition parameters and the rates of subatmospheric burning for the studied solid propellants is discussed.