Preparation and Combustion Performance of B/PVDF/Al Composite Microspheres

In order to solve the problems that boron nanoparticles (B NPs) are easy to agglomerate, low in combustion efficiency and difficult to ignite, 80 nm B NPs were doped with 50 nm aluminum nanoparticles (Al NPs) by electrospraying using 10 wt % PVDF as binders. The prepared B/PVDF/Al composite microspheres with diameter of 1 similar to 5 mu m were examined by scanning electron microscopy (SEM). Elemental maps confirmed the uniform distribution of B and Al NPs with the coating of polyvinylidene fluoride (PVDF). The thermal properties were tested by thermogravimetry-differential scanning calorimetry (TG-DSC), and the combustion process of samples in air was recorded by a high-speed camera. The results showed that PVDF can reacted with the oxide layer on the surface of Al (Al2O3) and B (B2O3) NPs to promote the combustion and energy release of B/PVDF/Al. In addition, the thermal reactivity of B/PVDF/Al increased as the Al NPs content increases. Al NPs could reduce the ignition energy of B/PVDF/Al, allowing it to burn stably in air. A thermal reaction mechanism was proposed to explain qualitatively the four-stage pattern of B/PVDF/Al decomposition observed in TG-DSC curves.