Bio-inspired synthesis of RDX@polydopamine@TiO2 double layer core–shell energetic composites with reduced impact and electrostatic discharge sensitivities

Abstract To reduce the impact and electrostatic discharge sensitivities of RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine), the polydopamine (PDA) and amorphous TiO2 were used as shell materials to construct a series of RDX@PDA@TiO2 double layer core–shell energetic composites with an RDX as the inner core and amorphous TiO2 as the exterior shell; and the PDA was employed as bio-adhesive agent coated on the surface of RDX to enhance the interfacial adhesion between RDX and amorphous TiO2. Then, by the characteristics of scanning electron microscopy (SEM), flourier-transform infrared (FT-IR) spectra, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), the double layer core–shell structure of RDX@PDA@TiO2 composites was indicated; and the reaction mechanism of the depositions of amorphous TiO2 shell was proposed. Furthermore, we explored the influence of different content, morphologies of amorphous TiO2 shell and thickness of PDA on the desensitization effect of RDX@PDA@TiO2 composites. Compared with pure RDX, the RDX@PDA@TiO2-1#, -2#, -3#, -4#, -5# samples exhibited significant enhancement of 4.0 J (26.7%), 15.3 J (102.0%), 28.2 J (188.0%), 30.0 J (200.0%), 21.8 J (145.3%) of impact energy, and 0.7 (50.0%), 1.0 J (71.4%), 2.2 J (157.1%), 7.2 J (514.3%), 5.9 J (421.4%) of electrostatic discharge energy, respectively. And the prepared RDX@PDA@TiO2 composites with thicker and lager particle size of amorphous TiO2 shell leaded to better desensitization effect. This work potentially provided an alternative method for improving vulnerability and transportation safety of RDX.