Effects of different mass ratios on mechanical properties and impact energy release characteristics of Al/PTFE/W and Al/PTFE/CuO polymer composites

Abstract

Aluminum/polytetrafluoroethylene (Al/PTFE) is an impact‐initiated material that is extensively utilized in military and civilian applications due to its insensitivity, high energy density and ease of manufacturing. To increase both its compressive strength and energy density, Al/PTFE was doped with various amounts of W and CuO particles. These polymer composites exhibit elastoplastic properties, as well as significant strain hardening and strain‐rate hardening during compression deformation. At a strain rate of 5000 s−1, the compressive strength of the Al/PTFE/W and Al/PTFE/CuO specimens with an additive content of 30% reaches a peak of 194.1 and 189.2 MPa, which corresponds to an increase of 40.3% and 36.8%, respectively, compared with the compressive strength of Al/PTFE (138.3 MPa). The homogeneous bonding strength between the additives and PTFE and the fact that the elastic PTFE nanofibers inhibit the extension of microcracks are the main mechanical strengthening mechanisms. The reaction of the composites under high‐speed impact is violent and accompanied by sputtering sparks, and the reaction efficiency was determined using an improved drop‐hammer apparatus. As the W content increases, the impact reactivity of Al/PTFE/W decreases monotonically. However, as CuO content increases, the reaction intensity of Al/PTFE/CuO initially increases, and then decreases. At a CuO content of 30%, the energy release efficiency of Al/PTFE/CuO reaches its maximum (10.49%), which is 84.4% higher than that of Al/PTFE. TG‐DSC and XRD tests were performed to analyze the pyrolysis process and elucidate the reaction mechanism. A gas–solid chemical reaction model was developed, and the reactivity arises from multiple factors.Highlights Typical elastoplastic characteristics as well as strain hardening and strain‐rate hardening were observed. The mechanical strengthening effect of W particles is higher than that of CuO particles of Al/PTFE specimen. The addition of W particles decreases the impact reactivity, but the addition of CuO particles improves the energy density of Al/PTFE. The reaction efficiency of Al/PTFE/CuO reaches a peak of 10.49%, which increased by 84.4% compared with that of Al/PTFE.