In situ self-crosslinking binder system − enhances the mechanical performance gain of composite energetic materials

Abstract

To improve the mechanical properties of microscale composite energetic materials, as well as to investigate their detonation performance, we used Toluene Diisocyanate (TDI) as a self-crosslinking curing agent based on an oil-in-water emulsion binder. We then prepared performance test samples with various microscale morphologies using the Direct Ink Writing (DIW) technique. We compared the mechanical properties of composite energetic materials, such as nanoindentation, quasi-static compression, and adhesion, and examined their infrared spectra, micromorphology, pore distribution, mechanical sensitivity, detonation performance, and combustion performance. The results indicated that with the in situ self-crosslinking binder system, the elastic modulus and hardness of the material were increased to 5.213 GPa and 0.100 GPa, respectively, which corresponds to an increase of approximately 638 % and 370 % compared to the original binder system. In the compressive strength test, the maximum stress increased by 104 %, and the maximum strain increased by 311 %, while the adhesion strength was enhanced by about 37.8 %. The infrared spectroscopy analysis demonstrated changes in the molecular structure due to in situ self-crosslinking. The improved surface morphology and more uniform pore size distribution also led to enhanced detonation performance and safety performance, with a detonation velocity increase of about 7.8 %, an increase in the critical detonation corner by 10°, a reduction in the critical detonation thickness by about 60.8 %, and a decrease in the critical detonation size to 0.3 × 0.3 mm. The impact sensitivity was reduced by 12.5 %, and the friction sensitivity was decreased by 30 %. Additionally, the material exhibited faster burn rates and larger flames. These findings provide significant scientific evidence for the regulation of mechanical properties and detonation performance of microscale composite energetic materials.