Abstract
Boric acid and other impurities on the surface of boron (B) particles can interact with hydroxyl-terminated polybutadiene (HTPB), which can weak the mechanical properties and energy release efficiency of boron-based solid rocket propellants. In this paper, solvent evaporation induced self-assembly was used to coat the surface of B particles with stearic acid (SA) and the SA@B composite particles were prepared. The effects of SA coating on the combustion performance of B particles and the mechanical properties of HTPB matrix composites were investigated. The results showed that the SA coating enhanced the oxidation efficiency of B particles in air. The heat of combustion value of the SA@B composite particles, reached up to 30.29 MJ/g. During the combustion of SA@B composite particles, there are fewer molten solid particles surrounding the flame, which enhances the stability of B particles combustion process. Furthermore, the SA coating effectively enhanced the dispersion of B particles in HTPB. At a stretching speed of 100 mm/min, the tensile strength of the SA@B/HTPB composite materials is higher than that of the B/HTPB composite materials. Moreover, when the mass loading of the SA@B composite particles reaches 50 wt%, the tensile strength of SA@B/HTPB composite materials achieves 0.63 MPa. The compatibility between B particles and HTPB can be effectively improved by surface-activated B particles with SA, which is of great significance for the storage stability of boron-based solid rocket propellants.