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利用动态热失重法(TGA)研究了一种新型的膨胀型无卤阻燃高抗冲聚苯乙烯(HIPS)热降解反应动力学及阻燃机理,通过对Kissinger模型和Coat-Redern(C-R)模型求解的热降解反应的动力学参数对比,最终确定反应的动力学参数.其中,反应级数n的确定是通过一般反应对Ea/RTmax取值范围的限定,利用最大热降解速率所对应的失重率αmax与n的关系,确定其取值.并采用TGA-FTIR及Py-GC/MS对材料气相产物及热裂解产物进行了阻燃机理的研究.研究表明,两种反应的热降解反应动力学参数基本一致,其中阻燃HIPS的平均表观活化能小于纯HIPS,说明在HIPS分解之前,无卤阻燃剂已经开始分解,释放的难燃气体(氨气及其衍生物、水蒸气等)在气相中起到阻燃的作用.同时阻燃剂的添加,促使反应向链转移反应飘移,使燃烧产物中非单体化合物增加,而在凝聚相中形成的致密的炭层结构也起到阻燃的效果.
The thermal degradation kinetics and flame retardant mechanism of a new type of intumescent halogen-free flame-retardant high impact polystyrene (HIPS) were studied by using dynamic gravimetric method (TGA). The Kissinger model and Coat-Redern (CR) Kinetic parameters of the thermal degradation reaction solved by the model, and finally determine the kinetic parameters of the reaction, in which the reaction order n is determined by the general reaction Ea / RTmax range of values, the maximum thermal degradation rate corresponding to Weight loss rate αmax and n to determine its value.And the flame retardant mechanism of the gas phase products and pyrolysis products were studied by TGA-FTIR and Py-GC / MS.The results showed that the thermal degradation reaction The kinetic parameters are basically the same. The average apparent activation energy of flame-retardant HIPS is less than that of pure HIPS, indicating that the halogen-free flame retardants have started to decompose before the HIPS decomposition. The released flammable gases (ammonia and its derivatives, water vapor Etc.) play the role of flame retardant in the gas phase.At the same time the addition of flame retardant, to promote the reaction to the chain transfer reaction drift, so that the non-monomeric compounds in the combustion products increased, and in the condensed phase formed dense carbon layer structure Play a flame retardant effect.