粉状聚酯固相缩聚反应动力学与降解行为的研究

Solid State Polymerization and Degradation of PET Powder

与固相缩聚工业生产用常规粒径聚酯相比,粉状聚酯的传质和反应均可得到增强。实验研究了不同粒径粉状聚酯(0.2～0.8 mm)在氮气氛围中的固相增黏规律,并采用模型方法对缩聚反应与降解行为进行了分析。结果表明粉状聚酯的固相缩聚反应是缩聚与降解的竞争过程,反应初期缩聚反应占主导地位,特性黏度随反应不断增加,后期降解反应占主导地位,特性黏度减小,存在一个特性黏度的最大值;粒径对固相缩聚反应影响明显,粒径的减小同时强化了缩聚与降解反应,缩聚与降解反应速率常数均增大,缩聚反应的活化能降低,降解反应活化能增大。

The solid-state polymerization（SSP） and degradation behaviour of poly（ethylene terephthalate）（PET） powder samples were investigated.The experimental data show that the polymerization and degradation reactions coexist and compete with each other during the SSP process.At the beginning of the SSP process,the polymerization reaction is dominant and the intrinsic viscosity increases with the processing of the SSP process;at the later stage of the SSP process,the degradation reaction becomes dominant and the intrinsic viscosity decreases.Therefore,during the whole SSP process,there exists a maximum intrinsic viscosity.It was also found that the powder size is a sensitive variable for SSP process of the PET;with the reduction of particle size,both the polymerization and degradation reactions are strengthened,and both the polymerization rate and degradation rate increase;however,the activation energy of polymerization decreases and that of degradation increases.