Dual-functional AP/CMC–Cu composite: synergistically enhanced catalytic decomposition and interfacial reinforcement for high-performance ammonium perchlorate-based propellants

Conventional solid combustion catalysts improve the combustion performance of composite solid propellants (CSPs) but degrade mechanical properties due to increased solid content and poor interfacial bonding. To resolve this, we propose a copper‑based multivalent synergistic catalysis strategy. Ammonium perchlorate (AP) was embedded into carboxymethyl chitosan copper (CMC–Cu) organic framework via droplet‑solution contact assembly, yielding a multifunctional AP/CMC–Cu composite. During thermal decomposition, CMC–Cu generates in‑situ Cu/CuO/Cu₂O multivalent active species that act as catalytic intermediates, accelerating electron transfer from ClO₄⁻ and reducing AP’s high‑temperature decomposition peak to 318.4 °C with a 39.4% decrease in activation energy. Meanwhile, abundant –NH₂ and –OH groups in CMC–Cu covalently cross‑link with toluene diisocyanate (TDI) in the binder, greatly enhancing AP‑binder interfacial adhesion. Propellants with CMC–Cu show a 41‑ms shorter ignition delay, 36.8% higher burning rate, tensile strength of 0.54 MPa, and adhesion index reduced to 1.24, effectively suppressing dewetting. This work offers new insights into multivalent copper catalyst design and provides a low‑cost route to AP‑based propellants with simultaneously improved combustion efficiency and mechanical performance.