Enhanced thermal and mechanical properties of PW-based HTPB binder using polystyrene (PS) and PS–SiO₂ microencapsulated paraffin wax (MePW)

Polystyrene (PS) microencapsulated paraffin wax (MePW) and PS–SiO₂ MePW were used to improve the form-stability of PW in hydroxyl-terminated polybutadiene-derived polyurethane (HTPB) binder. HTPB matrix containing different contents of PS MePW, PS–SiO₂ MePW, and PW were prepared. The chemical composition, crystallinity, microstructure, heat capacities, thermal stabilities, thermal reliabilities, leakage, and mechanical properties of the composites were compared using Fourier transforms infrared spectroscope, X-ray diffractometer, scanning electronic microscope, differential scanning calorimeter, thermo-gravimetric analyzer, thermal cycling test, leaking test, compression, and tensile tests, respectively. The results showed that the MePW/PW/HTPB composites were prepared without chemical reaction. The thermal stability and mechanical properties of PS–SiO₂ MePW/PW/HTPB increased more dramatically than that of PS MePW/PW/HTPB. With the increasing contents of MePWs, the PW leakage of the composites decreased, especially for PS MePW/PW/HTPB. Consequently, the MePW/PW/HTPB composites possess a potential application for PW-based polymer-bonded explosive system.