Energy and combustion performance of Al/PVDF composite films: Vapor-grown carbon fiber as a new additive

Vapor-grown carbon fibers (VGCF) have received significant attention due to their excellent properties, including low density, high specific modulus, super specific strength, and large specific surface area. To investigate the impact of VGCF on the energy and combustion performance of the aluminum (Al)/polyvinylidene fluoride (PVDF) metastable intermolecular composite (MIC) system, the composite films of Al/PVDF with varying VGCF contents were prepared using the spin-coating method. The micromorphology, crystal structure, mechanical property, energy, and combustion performance of the films were analyzed. The results demonstrate that the addition of VGCF greatly enhanced the system's performance, particularly in terms of hydrophobicity and tensile properties. Furthermore, the participation of VGCF also promoted gas generation during the combustion process, leading to an increase and subsequent decrease in reaction heat release and burning rate within a specific range. The optimal range for VGCF addition in composite films was determined to be 0.8 %–1.2 %. When the addition amount is 0.8 %, the heat release of total reaction, heat release of fluorination reaction, and burning rate reached maximum values of 4773 J·g⁻¹, 4551 J·g⁻¹, and 77.2 mm·s⁻¹, respectively. Compared with VGCF-0, the heat release increased by 687 J·g⁻¹ and 848 J·g⁻¹, respectively, and the combustion rate increased by nearly 13 %. When the addition of VGCF reached 2.0 %, a new product, Al₄C₃, appeared, deviating from the original performance trend and enhancing energy release and combustion performance. This study provides valuable insights for the application of VGCF as an additive in MIC materials.