Balanced Optimization of Hexanitrostilbene‐Based Polymer‐Bonded Explosive Properties via Micronization and Coating

ABSTRACT To address the poor inherent formability of hexanitrostilbene (HNS) that arises during micronization to achieve a low shock initiation threshold, this study explored a “micronization‒coating” synergistic strategy based on fluororubber, aiming to achieve a balanced optimization of safety, formability, and low initiation threshold of HNS within a mature and process‐compatible fabrication framework. First, HNS‐II was processed via recrystallization and mechanical ball milling to prepare ultrafine HNS‐IV with purity of 99.89%, of 0.435 µm, and specific surface area of 18.538 m 2 ·g −1 . A solution‐suspension method was subsequently used to facilitate the formation of 2 wt.% fluororubber (F2602) coating layer on HNS‐IV through interfacial interactions dominated by weak hydrogen bonding, van der Waals forces, and electrostatic attraction, yielding HNS‐IV‐based polymer‐bonded explosive (PBX). The characterization results revealed that the ultrafine and coated products retained good thermal stability. Compared with HNS‐II, ultrafine HNS‐IV exhibited comparable mechanical sensitivity, whereas the coated product HNS‐IV/F2602 showed an 8.00 J increase in impact energy and a 12% decrease in friction sensitivity, indicating improved safety after coating. Moreover, the coated product maintained excellent initiation performance. The shock initiation threshold of HNS‐IV/F2602 was only 0.169 J, indicating no significant desensitization compared with that of HNS‐IV (0.158 J). Furthermore, the coating significantly improved the formability of ultrafine HNS, increasing the compressive strength of HNS‐IV/F2602 from 4.268 MPa (HNS‐IV) to 18.597 MPa. This study confirms the effectiveness of the “micronization‒coating” synergistic strategy in achieving balanced, multidimensional performance enhancements of insensitive high explosives.