Sensitivity and Stability Improvements of NEPE Propellants by Inclusion of FOX‐7

Abstract

The performances of NEPE (Nitrate Ester Plasticized Polyether) propellants containing 1,1 diamino-2,2-dinitroethylene (FOX-7) were evaluated by means of theoretical calculation, combustion, mechanical and sensitivity experiments. It was found that, by the replacement of Cyclotetramethylene tetranitramine (HMX) with FOX-7 in NEPE propellants, the density (1) was maintained to be the same 1.80 g cm À3 , whereas the combustion temperature (T c ) decreased from 3700 K to 3592 K. The meaN molecular weight of combustion gas (M c ) was slightly increased (from 27.28 to 27.48 g mol À1 ) and the theoretical specific impulse (I sp o ) was decreased from 2615 to 2560 N s kg À1 . The content of FOX-7 was in the range of 0 % to 34 % in the formulation of NEPE propellant. It was also shown that the burning rate was increased along with the elevated pressure exponents from 0.44 to 0.48. Moreover, the tensile strength of the propellants at + 20 8C and + 50 8C was improved from 0.84 and 0.68 MPa to 1.06 MPa and 0.75 MPa, respectively, while the maximum elongation decreased from 64.1~86.1 % to 32.54 5.3 %. In terms of safety, the friction sensitivity of the propellant was improved (initiation probability decreases from 100 % to 88 % under pressure of 2.45 MPa) and the impact sensitivity (H 50 ) increased from 6.74 N m to 9.31 N m (2.5 kg hammer).

Molecular dynamics simulation on TKX-50/fluoropolymer

“…With the increasing temperature, the CED values of TKX-50 and four HE-polymers gradually decrease, indicating that the energy required to overcome the intermolecular force decline. This is consistent with the experimental fact that the sensitivity of the system gradually increases as the temperature increases [21,27]. The CED value of TKX-50 is above that of four HE-polymers.…”

Ballistic Studies on Fox-7 Based Triple Base Propellant for High Calibre Gun

“…Mishra et al [3] have also studied lower vulnerability of FOX-7 based, non-aluminized and aluminized, melt cast explosive with marginal decrease in performance compared to RDX based compositions. S Karlsson [8] has reported height of 50% explosion (H 50 ) 63 -79cm in Drop hammer tests and no reaction in the friction test (>340 N). A castable composition of FOX-7 and poly-glycidyl nitrate (Poly-GLYN) has also been studied by these researchers.…”

Comprehensive Evaluation of the Accelerated Aging Law of NEPE Propellants

“…NEPE combines the advantages of the double-base propellant and composite propellant. It is a new type of propellant with excellent energy performance and mechanical properties at present and represents the development direction of high-energy solid propellants [6][7][8]. However, in the storage process, this type of propellant is prone to complex aging phenomena, causing engine failure and leading to safety risks and economic losses [9][10][11].…”