Rational design of gradient structured fluorocarbon/Al composites towards tunable combustion performance.

Polytetrafluoroethylene/Aluminum (PTFE/Al) composite with high energy density and combustion reaction performance has received widespread attention in the field of propellants, explosives, and pyrotechnics. In order to precisely control combustion reaction and energy output performance, gradient structured PTFE/Al composite (mass and diameter gradient) has been designed and constructed through 3D printing technology. PTFE/Al ink is prepared by acoustic resonance mixing to control rheological properties (viscosity and modulus) for 3D printing technology. The largest reaction heat (7749.95 J/g) and burning rate (~130 mm/s) are achieved for gradient lines with diameter of 2.42 mm and mass ratio of 60:40 (PTFE/Al). Moreover, the progressive change from steady combustion to deflagration containing three stages of pressure output is observed for gradient structured PTFE/Al cylinder. This work reveals that gradient structure could provide new strategy to tune energy output and combustion performances, which can promote the practical application of PTFE/Al reactive materials. [ABSTRACT FROM AUTHOR]