Fabrication and characterization of surface modified HMX@PANI core-shell composites with enhanced thermal properties and desensitization via in situ polymerization

Abstract

To reduce the sensitivities and improve the thermal properties of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), a compact polyaniline (PANI) coating composites were fabricated via in situ polymerization on the surfaces of HMX modified with (3-Aminopropyl) trimethoxysilane (APTES) in this study. In-depth characterizations of the core–shell composites including FESEM, AFM, XPS, Raman spectra, XRD, HPLC, DSC and sensitivities test confirmed the successful PANI coating and the effective explosion performance optimization. The results indicated that the nano PANI were compactly coated on the surfaces of HMX crystals with low contents, and the APTES modification was vital to the coating of PANI which could increase -NH2 groups on the surfaces of HMX and form in situ points for polymerization. The chemical structures and polymorphs of the energetic crystal didn’t change during coating, and the PANI shell can stabilize the polymorphs and enhance the thermal decomposition of HMX. Furthermore, the sensitivities of core-shell composites reduced significantly by comparing with pure explosive, attributing to the buffering and isolation effect, and good conductivity of PANI shell.