Microscale investigations of mechanical responses of TKX-50 based polymer bonded explosives using MD simulations

Abstract

TKX-50 (dihydroxylammonium 5,5′-bistetrazole-1,1′-diolate) has high energy storage, high detonation speed, low sensitivity and low toxicity. The addition of polymer binders can provide better flexibility for TKX-50 to improve safety when they are subjected to external mechanical stimuli. In this work, four polymer binders, i.e. glycidyl azide polymer (GAP), polyglycidyl nitrate (PGN), polyethylene glycol (PEG) and polytetrahydrofuran (poly-THF), are added to TKX-50 with a mass fraction from 1% to 12%. Matrix notation calculations showed that the elastic moduli of nanocomposites TKX-50/polymers reduced with the increase of the polymer concentration. The microscopic behavior of deformation of TKX-50/polymers were studied using non-equilibrium molecular dynamics (NEMD) simulations. Dependence of tensile strength and Young’s modulus on the mass fractions and structure of polymer binders was investigated. It is found that the GAP and PGN self-crimp on the surface of TKX-50, while PEG and poly-THF are extended on the surface of TKX-50. Our results showed that polymer binders can improve the mechanical properties of TKX-50 with an order of poly-THF ≈ PEG > PGN > GAP.