基于DSC试验的DCP自加速分解温度的推算

Self accelerating decomposition temperature (SADT) calculation of dicumyl peroxide by using DSC tests

采用差示扫描量热仪(DSC)对小尺度过氧化二异丙苯(DCP)的热分解过程进行试验研究,利用基于等转化率Friedman微分法对热分析试验所得数据进行动力学分析,得出DCP的反应活化能的均值为160.82 kJ·mol^(-1)最后运用热爆炸理论对25 kg标准包装条件下的自加速分解温度(SADT)进行推算。结果表明,利用等转化率Friedman微分法计算所得的动力学参数在整个反应进程中并不是常数,表明DCP的热分解反应是一个固态的复杂反应过程。多重扫描速率下计算所得的动力学参数较单个扫描速率法可信度更高,推算所得DCP的SADT值与美式全尺寸试验值基本一致。

Dicumyl peroxide is usually employed as a source of free radicals, hardener, linking agent and initiator for polymerization. Due to its unstable and reactive nature, DCP has caused many thermal explosions and runway reaction incidents. In order to elucidate its thermal hazard characteristics, DCP was tested by using DSC analyzer with small sample mass, and the thermal data obtained from different scanning rate were analyzed by the isoeonversional Friedman method. The apparent activation energy Ea and pre-exponential factor A which depend on the reaction conversion are not constant, indicating that the decomposition mechanism of DCP is complex. The average apparent activation energy is 160.82 kJ. mol-1. Self-accelerating de- composition temperature （SADT） is the lowest ambient temperature at which the temperature increase of a chemical substance is at least 6 K in a specified commercial package during a period of seven days or less. The SADT is a very important parameter for assessing the safety management of reactive substances in storage, transportation and use. SADT is determined generally by one of four testing methods recom-mended by the UN orange book, and can be analytically and numerically evaluated by using experimental instruments. In the present study, DSC was used to investigate the decomposition of DCP. Based on the value of kinetic parameters, self-accelerating decomposition temperature （SADT） of 25 kg standard package was computed according to the thermal explosion theory. The results showed that the values of activation energy and pre-exponential factor of DCP obtained by using isoconversional Friedman method were more precise and reli-able compared to the single scanning rate method. Based on the calculation of these kinetic parameters, SADT can be rapidly evaluated. The value of SADT is in good agreement with the value of United States tests.