Thermal and mechanical reinforcement of a novel paraffin-based hydroxyl-terminated polybutadiene (HTPB) binder containing a three-dimension (3D) diurea-paraffin wax (DU-PW) for prevention of PW leakage

Leakage of paraffin wax (PW) is a major concern in the development of polymer bonded explosive (PBX) systems because it relates to the amount of PW that can be used as a desensitizer or a fuel, which, in turn, affects the mechanical performance and tolerance of PBX in high-temperature environments. Hydroxyl-terminated polybutadiene (HTPB) binders significantly contribute desirable polymer features to PBX. Thus, a three-dimension (3D) high-temperature non-flowing diurea-paraffin wax (DU-PW) composite was synthesized and creatively employed to a HTPB binder. DU-PW/PW/HTPB composites with different contents of the 3D DU-PW phase change material (PCM) were prepared through a cast molding process. The differential scanning calorimetry (DSC) results demonstrate that these composites can show high phase-change enthalpies and good thermal reliability. As observed from the scanning electron microscope (SEM) photographs, adding DU-PW can clearly reduce the number of holes caused by the leaked PW on the fracture surface of DU-PW/HTPB. Moreover, the addition of DU-PW can remarkably reduce the leakage of PW and improve the thermal stability as well as mechanical properties of the PW-based HTPB. These observations present the potential of utilizing form-stable PCM (FSPCM) to solve the problem of PW leakage in PBX systems.