Abstract Thermal decomposition behavior and decomposition mechanism of diisopropyl azodicarboxylate (DIAD) were characterized and analyzed by C80 micro-calorimetery and STA-FTIR-MS system. And thermal hazard of DIAD was assessed by using self-accelerating decomposition temperature (SADT) as the evaluation index. The results show that only one exothermic peak appeared in decomposition process, and that the onset temperature and peak temperature increase with heating rate, whereas the released reaction heat at the heating rates remained approximately constant at 945.67±23.45 kJ/kg. Based on C80 data, the calculated activation energy of DIAD decomposition ranges from 45 kJ/mol to 77 kJ/mol by Friedman method, while the reaction progress in the range of 0.10–0.90. During thermal decomposition process of DIAD, there is only one stage of weight loss, which starts at about 80 ℃, reaches to the maximum rate of weight loss at 138 ℃, and end up at about 150 ℃. The thermal decomposition mechanism of DIAD can be mainly summarized as the route that the C O single bond breaks at first, then C C breaks, and the N N bond breaks subsequently, then the C O bond or the C N bond breaks, final products such as H2O, CO2 etc. appear from further dissociation and oxidation of molecular ionic fragments at last. According to the above-metioned results, the calculated SADT of DIAD is 89.0 ℃ based on Semenov model, when packed in 25kg standard package.

中文翻译：

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偶氮二甲酸二异丙酯的热分解机理及热危害评价

摘要 采用C80微量热仪和STA-FTIR-MS系统对偶氮二甲酸二异丙酯(DIAD)的热分解行为和分解机理进行了表征和分析。并以自加速分解温度（SADT）为评价指标，对DIAD的热危害进行评价。结果表明，分解过程中仅出现一个放热峰，且起始温度和峰温随升温速率升高而升高，而在升温速率下释放的反应热基本保持在945.67±23.45 kJ/kg。根据 C80 数据，通过 Friedman 方法计算出的 DIAD 分解活化能为 45 kJ/mol 到 77 kJ/mol，而反应进程在 0.10-0.90 范围内。在DIAD的热分解过程中，只有一个失重阶段，80℃左右开始，138℃达到最大失重率，150℃左右结束。DIAD的热分解机理主要可以概括为CO单键先断裂，CC断裂，NN键随后断裂，然后CO键或CN键断裂，最终产物如H2O、CO2等最终由分子离子碎片的进一步解离和氧化而出现。根据上述结果，当采用25kg标准包装时，基于Semenov模型计算出的DIAD的SADT为89.0℃。NN键随后断裂，然后CO键或CN键断裂，最终分子离子碎片进一步解离和氧化，出现H2O、CO2等最终产物。根据上述结果，当采用25kg标准包装时，基于Semenov模型计算出的DIAD的SADT为89.0℃。NN键随后断裂，然后CO键或CN键断裂，最终分子离子碎片进一步解离和氧化，出现H2O、CO2等最终产物。根据上述结果，当采用25kg标准包装时，基于Semenov模型计算出的DIAD的SADT为89.0℃。