非线性等转化率的微、积分法及其在含能材料物理化学研究中的应用Ⅶ. HHTDD的热分解

Differential and integral isoconversional non-linear methods and their application in physical chemistry study of energetic materials:Ⅶ. Thermal decomposition of HHTDD

目的揭示2,4,6,8,10,12-六硝基-2,4,6,8,10,12-六氮杂三环[7.3.0.0^(3.7)]十二烷二酮-5,11(HHTDD)的放热分解动力学行为和对热抵抗能力。方法用高灵敏布鲁顿玻璃薄膜压力计研究空、高温低装填密度条件下HHTDD的熟分解过程。由热分解气体的标准体积(V_H)对时间(t)的关系曲线,得到HHTDD在不同温度下热分解反应的初速(W_0)、极大速度(W_(max))、诱导期(t_(in))、半分解期(t_(1/2))、极大速度到达时间(t_(max))、极大速度常数(k_(max))和平均叠合系数(k_(dh))。用非线性等转化率微、积分法所得的表观活化能E_α校验由lgx(x=W_0,W_(max),t_(in),t_(1/2),t_(max),k_0,k_(max),k_(dh))-1/T关系得到的表观活化能E_a。借助不同加热速率(β)下非等温DSC曲线离开基线的初始温度(T_0),onset温度(T_e),峰顶温度(T_p),Kissinger法和Ozawa法求得的热分解反应的表观活化能E_K和E_O)和指前因子(A_K),微量热法确定的比热容(C_p),以及密度(ρ),热导率(λ)和分解热(Q_d,取爆热之半)数据,Zhang-Hu--ie-Li公式,Hu-Yang-Liang-Xie公式,Hu-Zhao-Gao公式,Zhao-Hu-Gao公式,Smith方程,Friedman公式和Bruckman-Guillet公式,计算HHTDD在β→0时的T_0,T_e和T_p值(T_(00),T_(e0)和T_(p0))、热爆炸临界温度(T_(be)和T_(bp))、绝热至爆时间(t_(TIad))、撞击感度50%落高(H_(50))和热点起爆临界温度(T_(cr))。结果 E_α与各特征值所得的对应E_a间的相对误差在±5%以内。得到了评价HHTDD热安全性的结果:T_(SADT)=T_(e0)=456.91K,T_(SADT)=T_(p0)=460.30K,T_(be0)=467.58K,T_(bp0)=470.03K,t_(TIad)=10.7s,H_(50)=20.40cm,T_(cr)=441.30K。结论 HHTDD有好的对热抵抗能力。

Aim To expose the kinetic behaviour of exothermic decomposition and the heat-resistance of 2, 4, 6,8, 10, 12-hexanitro-2, 4, 6, 8, 10, 12-hexaazatricyclo[ 7.3.0. 0^3＇ 7 ] dodecane-5, 11-dione （HHTDD）. Methods The thermal decomposition processes of HHTDD under the conditions of vacuum and low loading density at high temperature are studied by using a highly sensitive Bourdon glass membrane manometer. The characteristic data, initial decomposition rate （W0）, maximum decomposition rate （Wmax）, induction period（ tin ）, half decomposition period（ t1/2 ）, time to maximum decomposition rate （tmax）, initial rate constant （k0）, maximum rate constant （kmax）, average overlap coefficient（kdh ） at different temperatures for the thermal decomposition reaction of HHTDD are obtained from the obtained standard volume of gas evolved （Vn） vs. time （t） curves. The values of apparent activation energy Ea obtained by differential and integral isoconversional non-linear methods are used to check the validity of the values of apparent activation energy E, obtained by plotting lg （ x = W0, Wmax, tin, t1/2, tmax, k0, kmax, kdh） against 1/T. With the help of the initial temperature （ T0 ）, at which DSC curves deviates from the basline, the onset temperature （To） and maximum peak temperature （Tp） from the non-isothermal DSC curves of HHTDD at different heating rates （β）, the thermal decomposition activation energy （ Ek and E0 ） and pre-exponential constant（Ak） obtained by Kissinger＇s method and Ozawa＇s method, the values of specific heat capacity（Cp） obtained by microcalorimetry, density（ρ） and thermal conductivity（A）, the decomposition heat （Qd, taking half-explosion heat）, Zhang-Hu-Xie-Li＇s formula, Hu-Yang-Liang-Xie＇s formula, Hu-Zhao-Gao＇s formula, Zhao-Hu-Gao＇s formula, Smith＇s equation, Friedman＇s formula and Bruckman-Guillet＇s formula, the values（ T00, TEo and TP0） of TC, Te and Tp corresponding to β→4）, thermal explosion temperature （ Tbe0 and Tbpo ）, adiabatic time-W-explosion （ tTlesd ）, 50% drop height （Hs0） of impact sensitivity, critical temperature of hot-spot initiation （Tot）, of HHTDD are calculated. Results The relative error between the values of Eα and E. corresponding to each characteristic datum is within ＋5%. The following results of evaluating the thermal safety of HHTDD are obtained： TSADT = Te0 =456. 91 K, Tsadt = Tp0 =460. 30 K, Tbe0 =467.58 K, Tbp0 = 470. 03 K, tTlad = 10. 7s ,H50 = 20. 40 cm, Ter, = 441.30 K. Condusion HHTDD has good heat-resistance ability.