Preparation of hierarchical core-shell Al-PTFE@TA and Al-PTFE@TA-Fe architecture for improving the combustion and ignition properties of aluminum

Due to the dense oxide film on the surface of aluminum powder, the combustion efficiency of aluminum powder is reduced and the ignition temperature is increased. The addition of polytetrafluoroethylene (PTFE) and the use of ball milling can effectively improve the ignition and combustion properties of aluminum powder. However, the Al-PTFE composite prepared by ball milling usually limits the combustion efficiency of aluminum due to its low PTFE content. In addition, the presence of the F element on the surface of the Al-PTFE particles makes Al-PTFE and HTPB adhesives produce interface effects, making it difficult for Al-PTFE composites to be used in composite propellants. Herein, through simple tannic acid (TA) self-aggregation and the self-assembly reaction of TA with iron ions, the Al-PTFE@TA and Al-PTFE@TA-Fe composites with hierarchical core-shell structure are prepared. Scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and thermogravimetry and differential scanning calorimetry (TG-DSC) are uesd to characterize these composites. The experimental results show that the establishment of TA and TA-Fe interface layer can effectively decrease the ignition temperature of Al-PTFE composite in the oxygen. In addition, Al-PTFE@TA and Al-PTFE@TA-Fe can effectively inhibit aluminum agglomeration compared with Al-PTFE during the combustion process. [Display omitted] •Al-PTFE@TA and Al-PTFE@TA-Fe with hierarchical core-shell structure are prepared.•Al-PTFE@TA and Al-PTFE@TA-Fe can inhibit aluminum agglomeration.•Al-PTFE@TA and Al-PTFE@TA-Fe have the lower ignition temperature.