Ultrafine RDX (cyclotrimethylene trinitramine, C₃H₆N₆O ₆) particles were prepared by ultrasonic assisted spray method, and the RDX-based composites with various polymer binders were obtained by water suspension method. The binders in composites are as follows: ACM (AR-12, AR-14, AR-71), VitonA and F2602. The binding energies between crystal surfaces of RDX and the binders were calculated, which show that the binding energies of RDX and ACM are higher than those of RDX and other binders. Then the crystal morphologies, crystal structures, thermal decomposition properties and mechanical sensitivities of raw RDX, ultrafine RDX and the RDX-based composites were characterized. Finally, the static mechanical properties of the RDX-based composites were tested and the detonation pressures of samples was calculated. The results show that there are different degrees of improvement in the combination properties of RDX after coating by the polymers, and AR-71 is the most suitable binder for coating RDX.

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A kind of liner suitable for HTPE propellant was developed by constructing HTPE and HTPB blend adhesive system. The effects of different solid fillers and crosslinker on the mechanical properties, adhesive properties, and ablation resestance and migration resistance of the liner were investigated. The surface mophology of the liner was observed by SEM. The results show that when the blending ratio of HTPE and HTPB is 1:5, 7 % molecular sieves, 7 % silica and chain extender TMP were added respectively, the tensile strength of the liner reaches 2.30 MPa at 20 ℃, and the fracture elongation is 203 %, the linear ablation rate is 0.59 mm･s^-1, the pull-off strength of the shell⁄insulator⁄liner⁄propellant reaches 0.90 MPa, and the mobility of nitrate ester plasticizer is 4.3 %.

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In this study, to mitigate blast wave in a specific direction, additional high walls were installed over a standard blast wall and their blast mitigation performances were experimentally investigated. A blast wave generated by an explosion of 1.00 g pentaerythritol tetranitrate pellets was measured by pressure transducers mounted on a steel plate simulating the ground surface. An I-shaped wall and rectangular C-shaped walls, which had lateral components, were used as the additional walls. The walls were made of steel plates in order to avoid deformation. As compared to the I-shaped wall, the C-shaped wall reduced the peak overpressure more behind the wall near the explosion point; however, it intensified the blast wave more on the opposite side of the wall. When the C-shaped wall was distanced from the explosive, the blast pressure behind the wall was mitigated for the entire distance, and the pressure increment on the opposite side caused by the reflected shock wave was suppressed. The results indicated that the high C-shaped wall additionally placed far from the explosive was effective in protecting objects in the specific direction from the blast wave.

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Blast wave mitigation from a straight tube using a metal foam plate (MF) was evaluated to examine effects of such a plate on a tube floor by measuring the blast pressures outside the tube. MF were installed on the floor of a straight, 330-mm-long square tube with a 30×30 mm² cross-section. The 5-mm-thick MF layer did not contact the test explosive. One tube end was closed. A specially designed small detonator that contained 100 mg lead azide was ignited near the closed tube end as the test explosive. The MF mitigated the blast wave. The MF, installed for whole length, absorbed approximately 40 % of the explosive energy. The results underscored that specially designed materials and a tube or tunnel interior surface structure can mitigate blast pressure remarkably.

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