膨胀阻燃聚丙烯的热降解动力学研究

Kinetic Study on Thermal Degradation of Intumescent Flame Retardant Polypropylene

利用双辊混炼机制备了共混型阻燃聚丙烯(PP)材料,并用热重(TG-DTG)方法研究了PP、PP/MPP和PP/MPP/PER在N2气氛下以不同升温速度时的热降解动力学行为,以此探讨阻燃性能与热降解行为的关系。试验发现,加入阻燃剂后材料的初始分解温度提前。利用Kissinger法和Flynn-Wall法求取了材料的活化能,发现两种方法求取的结果相一致。添加阻燃剂后,材料的活化能明显提高,说明阻燃剂使PP提前分解成炭,产生隔热、隔氧作用,阻止了PP的进一步氧化分解。采用Crane方程求得材料热降解反应级数均接近1。

For the purpose of exploring the relation between flame retarding property and thermal degradation, the intumescent flame retardant polypropylene composites were prepared by using two-roll mill, and with different heating rate, the thermal degradation kinetics behaviors of PP and flame retardant PP composites in nitrogen atmosphere by means of TG were studied. It was found that with flame retardant agent added, the initial decomposition temperature of PP occurred in advance. The thermal degradation of materials were simulated by Kissinger and Flynn-Wall methods, activation energies obtained by the two methods were similar, and the activation energy of flame retardant PP was higher than that of PP. It showed that the flame retardant agents induced PP to decompose into carbon ahead of time, insulate it from heat and oxygen, and hold back its further oxidation and decomposition. The reaction order was close to 1 according to the Crane theory.