Al/Cr_(2)O_(3)对硝化棉热分解过程的影响

Effect of Al/Cr_(2)O_(3) on the Thermal Decomposition Process of Nitrocellulose

为了探讨Al/Cr_(2)O_(3)纳米铝热剂对硝化棉(NC)热分解过程的影响,采用差示扫描量热法(DSC)及热重/红外联用技术(TG/DTG-FTIR)研究了单组分NC和Al/Cr_(2)O_(3)/NC复合物的热分解反应过程。运用Kissinger法、Starink法、Kissinger-迭代法和Ozawa-迭代法计算得到NC及Al/Cr_(2)O_(3)/NC的表观活化能。通过FWO法、KAS法和Friedman法得到NC和Al/Cr_(2)O_(3)/NC热分解过程的动力学参数,并引入修正后的?esták-Berggren经验方程对相应热分解反应动力学模型进行重建。结果表明,Al/Cr_(2)O_(3)纳米铝热剂可使NC热分解反应的表观活化能降低33.7kJ/mol,热点火温度降低3.5℃,热爆炸临界温度降低3.0℃。Al/Cr_(2)O_(3)/NC的热分解反应过程遵循n级动力学方程f(α)=7.25α^(0.73)(1-α)^(2.12)。在Al/Cr_(2)O_(3)催化作用下,NC首先断裂O—NO_(2)键,最终释放H_(2)O、CO_(2)、CO、NO_(2)、NO、N_(2)O、HCHO和HCOOH气体产物。

To explore the effect of Al/Cr_(2)O_(3) nanothermite on the pyrolysis characteristics of nitrocellulose(NC),the differential scanning calorimetry(DSC)and the thermogravimetry/derivative thermogravimetry coupled with Fourier transform infrared spectrometry(TG/DTG-FTIR)techniques were employed to investigate the thermal decomposition processes of NC and Al/Cr_(2)O_(3)/NC.The apparent activation energies of NC and Al/Cr_(2)O_(3)/NC were calculated by Kissinger,Starink,Kissinger-iterative,and Ozawa-iterative methods.Kinetic parameters of the pyrolysis process of NC and Al/Cr_(2)O_(3)/NC were obtained by FWO,KAS,and Friedman methods,and the modified esták-Berggren empirical equation was used to reconstruct the kinetic models of their pyrolysis reactions.The results showed that the apparent activation energy,the thermal ignition temperature,and the critical temperature of thermal explosion of NC were reduced by 33.7 kJ/mol,3.5℃,and 3.0℃,respectively,with the introduction of Al/Cr_(2)O_(3) nanothermite.The pyrolysis process of Al/Cr_(2)O_(3)/NC follows the n-order kinetic equation f(α)=7.25α0.73(1-α)2.12.Under the catalysis of Al/Cr_(2)O_(3),the O—NO_(2) bond could be first ruptured during NC decomposition,and then H_(2)O,CO_(2),CO,NO_(2),NO,N_(2)O,HCHO,and HCOOH gas products were generated and released.