聚对苯二甲酸乙二醇酯的溶胀聚合

Swollen-state Polymerization of Poly(ethylene terephthalate)

以联苯 /联苯醚混合物 (2 6 :74v/v)为溶胀剂 ,研究了聚对苯二甲酸乙二醇酯 (PET)预聚体颗粒的溶胀聚合 ,探讨了影响PET溶胀的因素以及温度、催化剂 (Sb2 O3 )、试样结晶度对反应速率的影响 ,并对PET的固相聚合与溶胀聚合进行了比较。实验结果表明 ,PET溶胀后 ,分子链的自由体积增大 ,链端活动范围扩大 ,缩聚副产物扩散加快 ,从而使反应速率增加 。

In order to obtain higher molecular weight poly (ethylene terephthalate)(PET), the swollen state polymerization(SwSP) of PET in granular form was carried out in biphenyl and diphenyl ethyle mixture that is used as the swelling solvent. It was found that the swelling of PET was strongly depend on the temperature, solubility parameter of solvent, and particle size of PET. It was shown that the reaction rate was enhanced by such factors as the addition of catalyst(Sb 2O 3)to the solvent, low degree of crystallization, and high degree of swelling, i.e. the amount of impregnated solvent in swollen PET. It was considered that compared with the solid state polymerization of PET, the rapid increase in average molecular weight during SwSP can be contributed to the increase in the free volume of molecular chain, fast diffusion of condensates and increased mobility of reactive chain ends.