Preparation of n-Al@PVDF Composites by Electrospray Method and Study on Its Combustion Properties

Abstract

In order to improve the exothermic properties of aluminum nanoparticles, an electrostatic spraying method was employed to prepare core-shell structured n-Al@PVDF (polyvinylidene fluoride) composites. The maximum combustion pressure (pmax) and the pressure rise rate (pmax/Δt) of the composites as the main indexes were introduced to assess their combustion performance by the influence of the inner diameter of the needle, the injection rate, receiving distance, and voltage of the electrospray apparatus. Transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to study the morphology and microstructure of the composite particles, and the results were compared with the samples prepared by the mechanical mixing method. The results showed that polyvinylidene fluoride modified aluminum nanoparticles prepared by using the electrostatic spraying method had regular morphology, and the core-shell structure is visible, and the n-Al@PVDF composites had the higher maximum combustion pressure and the pressure rise rate than that prepared by the mechanical mixing method, showing better combustion performance. Moreover, different parameters in the preparation process affected the performance of the composites. The voltage had the greatest influence on the performance of the prepared samples, but the influence of needle diameter is the least. The composite particles prepared under the needle diameter of 0.60mm, injection rate of 0.5mL/h, receiving distance of 8cm and voltage of 14kV had the most regular morphology and the best combustion performance. Additionally, those composites can react more completely in the combustion process, while the stable α-Al2O3 was the primary product.