Preparation and characterization of energetic composite films with mutual reactions based on B/PVDF mosaic structure

Abstract

In this study, to solve the boron oxide (B2O3) formed on the boron (B) surface, which reduces the reactivity and energy release. The energetic composite films with mutual reactions of B as fuel and polyvinylidene fluoride (PVDF) as oxidant are designed, based on the mosaic structure. Then, samples with different contents of B are successfully prepared by the novel synergistic emulsification and transient freezing methods. The morphology and composition results show that B is embedded in PVDF films, which makes the energetic composite films have excellent hydrophobicity and oxidation resistance. Interesting, the thermal analysis results show that in the low-temperature stage, the addition of B advances the initial decomposition temperature of PVDF; in the high-temperature stage, the gas product hydrogen fluoride (HF) of PVDF decomposition has a pre-ignition reaction (PIR) with B2O3, which destroys the shell of B2O3 and accelerates the oxidation of internal active B. And the heat release of 50 % B content is the highest (3845.4 J/g). Furthermore, the ignition and combustion results show that all samples can be ignited smoothly and easily. But the combustion performance is greatly affected by the content of B. Finally, the reaction mechanism of samples is preliminarily obtained by molecular model through the characterization of combustion products. These results show that composite films with mutual reactions based on B/PVDF mosaic structure have an excellent prospect for application in thermite with fluoropolymer.