阻燃PET的热降解动力学

STUDY ON THERMODEGRADATION KINETICS OF FLAME RETARDED PET

利用双螺杆挤出机挤出造粒制备了共混型阻燃PET材料,并利用TG方法研究了PET和阻燃PET在N2气氛下以一定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,在失重20%以前,阻燃PET的活化能低于PET的活化能,当失重超过30%以后,阻燃PET的活化能超过了PET,说明阻燃剂使PET提前分解成炭,隔热、隔氧阻止了材料的进一步氧化分解;阻燃剂的加入使同一温度下PET的不同失重率所对应的时间缩短,在同一温度下阻燃PET失重一半的时间t0.5也有较大幅度的缩短,即热稳定性下降,这一点与阻燃剂能够降低PET初始分解温度、提前分解成炭有密切的关联。

The blending flame retarded PET materials was prepared by extrusion and granulation of twin-screw extruder and with a certain heating rate, the thermal decomposition kinetics behaviors of PET and flame retarded PET in nitrogen atmosphere by means of TG was studied. The relation between flame retarding property and thermal decomposition was studied. It shows that with the flame retardant added, the initial decomposition temperature of PET occurres in advance. The activation energy of flame retarded PET is below that of PET before 20% mass loss and the former surpasses the latter after 30% mass loss. The flame retardant advances PET to decompose into carbon, insulate it from heat and oxygen, and hold back its further oxidation and decomposition. The addition of flame retardant shorten the corresponding times of different decomposition rates under the same temperature, that is the decrease of thermal stability, which is closely related with the ability flame retardant, it can decrease the initial decomposition temperature and advance PET to decompose into carbon.