Construction of boron-based double-layer core-shell structure composites and their combustion energy release characteristics

Abstract

Although boron (B) powder has a high energy density, the high boiling point oxide layer (B2O3) on the surface seriously hinders the combustion of internal B particles, which further limits the use of B powder. In order to solve this issue, polydopamine (PDA) was used as a sandwich layer (sandwich layer used to connect solid-liquid interface) between the original B powder and liquid perfluoropolyether (PFPE), and then a double-layer core-shell structure B@PDA@PFPE was prepared through the electrostatic self-assembly method. Herein, PDA not only helps remove naturally occurring B2O3, but also provides more active sites and improves the reactivity of B and PFPE. The results indicate that the B@PDA@PFPE has excellent combustion flame and energy release characteristics due to the superior dispersion and reactivity of PFPE. Compared to that of the original B powder, the results of thermal decomposition and combustion heat of B@PDA@PFPE with 30%PFPE discloses that the oxidation temperature drops by about 19.5 ℃, the combustion efficiency rises by about 22.3 %, and the flame expansion rate and flame temperature rise by approximately 40 times and 95.6 ℃, respectively. Therefore, the construction of double-layer core-shell structure effectively promotes the combustion of B powder. This work provides a new strategy for the application of B powder.