Dynamic disulfide bonds and hydrogen bonds give BAMO/THF-GAP based adhesives excellent self-healing and mechanical properties

During the storage, transportation and loading processes of composite solid propellants, micro-cracks and defects will be generated, which will shorten their service life. By developing composite solid propellants with self-repairing functions, it is expected to solve these problems. Therefore, this study proposes a novel energetic self-healing binder based on dynamic disulfide bond exchange reactions and hydrogen-bond reorganization. BAMO/THF is copolymerized with GAP matrix as the soft segment; isophorone diisocyanate (IPDI) and 2,2′-diaminodiphenyl disulfide (2-AFD) are selected as the hard segments to synthesize a series of self-repairing adhesives (PGPU). After 96 hours of high and low temperature impact, the mass change rate of PGPU samples is less than 0.01%, the tensile strength change rate is less than 6%, and the fracture elongation rate change rate is less than 4%. It has excellent mechanical stability under high and low temperature environmental impact. Among them, the toughness of PGPU-3 reaches 38.93 MJ·m -3 , and the self-repair efficiency reaches 84.47% after 16 hours of fracture at 75 °C. Based on this, self-repairing composite solid propellants are prepared, and the self-repairing efficiency of the tensile strength can reach 84.28%, and the burning rates at 1 MPa, 3 MPa, and 5 MPa pressures are 10.07 mm/s, 12.19 mm/s, and 13.82 mm/s, respectively, with excellent combustion performance. This study provides new theoretical basis and feasibility schemes for designing high-energy-density self-repairing adhesives.