聚对苯二甲酸乙二酯固相缩聚的研究

聚对苯二甲酸乙二酯(PET)薄膜经固相缩聚反应后,用凝胶色谱法测定产物的分子量、分子量分布和环状齐聚物含量.结果发现,PET在180—240℃之间的固相缩聚反应除了在220℃以上略有偏离外,基本遵循二级动力学规律。反应活化能为24.29kcal/mol,与熔融聚合反应活化能接近;反应速度常数比相应温度下后者的速度常数(外推值)大;分子量分布略有加宽;环状齐聚物含量随反应温度提高和反应时间的延长而逐步减少.

Study on Solid Phase Polymerization of Polyethylene Terephthalate

Polyethylene terephthalate(PET) films were polymerized in solid phase, the molecular weight,molecular weight distribution (MWD)and cyclic oligomer content of the products were determined by GPC. It shows that except for a little deviation occurring above 220℃, the solid phase polymerization reaction of PET films follows basically second order relationship at 180—240℃, the reaction activation energy is 24.29kcal/mol(101.68kJ/mol), which is close to that of melt polymerization of PET. But the rate constants seem abnormally high when compared with those obtained at similar temperature in the melt, MWD is a little broader and the amount of cyclic oligomers in PET samples decreases gradually as temperature increases and as reaction time prolongs during solid phase polymerization.