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Non‐Isothermal Decomposition Kinetics, Heat Capacity, and Thermal Safety of 2‐Nitroimino‐5‐Nitro‐Hexahydro‐1,3,5‐Triazine (NNHT)
Author(s) -
Zhang JiaoQiang,
Gao HongXu,
Ma HaiXia,
Fei JingYin,
Zhao FengQi,
Wang BoZhou,
Hu RongZu,
Xu KangZhen,
Song JiRong,
Zhang Hai
Publication year - 2011
Publication title -
propellants, explosives, pyrotechnics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.56
H-Index - 65
eISSN - 1521-4087
pISSN - 0721-3115
DOI - 10.1002/prep.200900099
Subject(s) - heat capacity , thermodynamics , thermal decomposition , isothermal process , adiabatic process , chemistry , isothermal microcalorimetry , kinetic energy , analytical chemistry (journal) , enthalpy , physics , organic chemistry , quantum mechanics
The kinetic equation describing the thermal decomposition reaction of NNHT obtained by TG‐DTG data, integral isoconversional non‐linear method and integral method of treating TG‐DTG curves is ${{\rm{d}}\alpha /{\rm{d}}t = 10^{12.86} (1 - \alpha {\rm{)}}^{{3 \over 2}} {\rm{e}}^{ - 1.5849 \times 10^4 /T} }$ . The specific heat capacity ( C p ) of NNHT was determined with the continuous C p mode of the microcalorimeter. The equation of C p ( T ) was obtained. The standard molar heat capacity of NNHT was 218.41 J mol −1 K −1 at 298.15 K. With the help of the onset temperature ( T e ) and maximum peak temperature ( T p ) from the non‐isothermal DTG curves of NNHT at different heating rates ( β ), the apparent activation energy ( E K and E O ), and the pre‐exponential constant ( A K ) of the thermal decomposition reaction obtained by Kissinger’s method and Ozawa’s method, C p obtained by microcalorimetry, density ( ρ ) and thermal conductivity ( λ ), the decomposition heat ( Q d , taking half‐explosion heat), Zhang‐Hu‐Xie‐Li’s formula, Smith’s equation, Friedman’s formula, Bruckman‐Guillet’s formula, and Wang‐Du’s formulas, the values ( T e0 and T p0 ) of T e and T p corresponding to β →0, thermal explosion temperature ( T be and T bp ), adiabatic time‐to‐explosion ( t TIad ), 50 % drop height ( H 50 ) of impact sensitivity, critical temperature of hot‐spot initiation ( T cr ), thermal sensitivity probability density function [ S ( T )] versus temperature ( T ) relation curves for spheroidic NNHT with radius of 1 m surrounded with ambient temperature of 300 K , peak temperature corresponding to the maximum value of S ( T ) versus T relation curve ( ${T_{S(T){\rm{max}}} }$ ), safety degree (SD), and critical ambient temperature( T acr ) of thermal explosion of NNHT are calculated. The following results of evaluating the thermal safety of NNHT are obtained: T SADT = T e0 =453.34 K, T SADT = T p0 =454.86 K, T be =462.68 K, T bp =467.22 K, t TIad =1.03 s, H 50 =17.69 cm, T α =461.4 K. SD=72.74 %, P TE =27.26 %, and T acr =321.96 K.