Synergistic enhancement of ammonium perchlorate in LP/PVA-based electrically controlled solid propellants: In-depth insights into thermal decomposition kinetics and combustion behavior

Lithium perchlorate/polyvinyl alcohol (LP/PVA)-based electrically controlled solid propellants (ECSPs) exhibit significant potential for novel controllable propulsion; however, their complex thermal decomposition behavior restricts practical application. To overcome these limitations, this study introduces ammonium perchlorate (AP) as a synergistic oxidative modifier. Herein, the thermal decomposition characteristics and non-isothermal kinetics of LP/AP/PVA-based ECSPs were systematically investigated. Simultaneous thermal analysis reveals that the addition of AP transforms the slow, multi-step decomposition of the LP/PVA-based ECSP into a single, vigorous stage. This leads to a more concentrated energy release and concurrently decreases the main decomposition peak temperature from 326.17 °C to 259.5 °C. Kinetic analysis via the model-free isoconversional Kissinger-Akahira-Sunose (KAS) method demonstrated that the average activation energy (Ea) was significantly reduced from 169.24 kJ/mol for the pristine LP/PVA-based ECSP to 111.08 kJ/mol for its optimized LP/AP/PVA counterpart. The variation trend of Ea reveals a fundamental shift in the rate-limiting step: from a diffusion-controlled process hindered by a physical barrier of char layer and molten salt, to a chemical reaction-controlled process accelerated by AP. Based on these findings, a novel “acid-catalyzed and radical-synergistic initiation” mechanism is proposed: HClO 4 generated from AP decomposition induces the dehydration of the PVA backbone at the early stage, while ·OH radicals provide a low-energy-barrier reaction pathway. Consequently, the combustion performance was enhanced, evidenced by a 142.1% increase in burning rate, a 21.9% reduction in ignition delay, and a 13.1% decrease in the required electrical energy for ignition. This work not only presents an effective strategy for tuning ECSP performance but also provides fundamental kinetic insights into the synergistic enhancement effect, offering experimental support for the design of novel ECSP formulations.