Desensitization and stabilization of HMX crystals by intercalation of crosslinked graphene oxide

It is challenging to balance the energy and sensitivity for the development of energetic materials (EMs). In this paper, the HMX crystals with improved energy density but lower sensitivity have been prepared by intercalation of triaminoguanidine-glyoxal crosslinked graphene oxide (GO-TAGP). The morphologies and structure of intercalated HMX crystals depend largely on the content of GO-TAGP. Notably, the presence of a higher percentage of GO-TAGP leads to a transition of HMX crystal structure to the γ-form. It has been shown that with the constraint of GO-TAGP, HMX crystals show a significant enhancement in energy content. With intercalated 3.7 wt% of GO-TAGP, the density of modified HMX increased to 1.93 g·cm⁻³ with higher heat of explosion (5421 J·g⁻¹) and higher heat of formation (140.6 kJ·mol⁻¹) than that of neat HMX (1.89 g·cm⁻³, 5242J·g⁻¹ and 75.8kJ·mol⁻¹). Importantly, remarkably improved thermal stability of modified HMX have been achieved, disclosing an excluded polymorphic transition via DSC and the variable-temperature powder XRD technique. In specific, the modified HMX with intercalated 1.0 wt% GO-TAGP exhibits superior safety performance with the impact energy increased to 26.5 J, even 780 % higher than pristine HMX (3 J). The detonation performance of as-modified HMX was tested, achieving an enhanced detonation velocity of 9254 m·s⁻¹, whereas that of raw HMX is only 9010 m·s⁻¹. This approach could offer an efficient strategy to enhance the energy content of HMX with significantly improved thermal stability and safety performance.