Reaction mechanism, insensitivity and mechanical property of PTFE–Mg–W composites with magnesium particles surface modification

This paper aims at enhancing impact insensitivity of polytetrafluoroethylene (PTFE)–Mg–W without sacrificing bulk of energy released in the reaction and optimizing mechanical properties of PTFE–Mg–W by magnesium surface treatment. The reaction energy results indicate that the reaction energy of PTFE–Mg–W (modified 1 min) in oxygen decreases slightly to 7905 J·g⁻¹ compared with that of PTFE–Mg–W (unmodified) which is 8533 J·g⁻¹. Under impact condition (impact velocity between 16.232 and 17.726 m·s⁻¹), compared with PTFE–Mg–W (unmodified), the initiation time before ignition of PTFE–Mg–W (modified 1 min) delays 50 μs; the absorbed energy needed for ignition of PTFE–Mg–W (modified 1 min) increases by 67.9%. This increase in impact insensitivity of PTFE–Mg–W can be contributed to the formation of passivated layers of magnesium particles after modification which effectively weakens the total interface area among reactive components and partly contributes to the loss of released energy of PTFE–Mg–W after magnesium modification. The quasi-static and dynamic compression results show that PTFE–Mg–W (modified 1 min) possess the highest strength and the best ductility.