PET-PEG嵌段共聚物的热性能和流变性

THERMAL AND RHEOLOGICAL PROPERTIES OF PET-PEG COPOLYMERS

酯交换法合成了一系列不同PEG含量的PET-PEG嵌段共聚物,并以差示扫描量热分析法(DSC)研究了这些嵌段共聚物及纯PET的热性能。用毛细管流变仪研究了不同温度和不同长径比条件下它们的流变性能。发现PET和PET-PEG嵌段其聚物均为切力变稀流体,且随切变速率增大,非牛顿指数变小。粘流活化能E_(?)在PEG含量为15wt％时有极小值,在PET含量为30wt％时有极大值。

Polyethylene glycol (PEG) of low molecular weight was successfully introduced into polyethylene terephalate (PET) to polymerize PET-PEG block copoly-mer. And the samples with different PEG contents were studied using differential scanning calorimeter (DSC) and capillary rheometer. The DSC curves and the rheological properties of PET-PEG copolymers under different temper-ature (when the ratio of length to diameter (L/D) was 50) and at different L/D at 270C were obtained. It was found that the contents of PEG had great influence on PET-PEG copolymcrs' properties. The copolymers had lower viscosity at higher shear rate and relatively lower non-Newton index compare with the pure PET which indicated that the copoly-mers had larger elasticity. Activation energy for flow was changed with the PEG contents and it reached the maximum at 30 wt% PEG contents while the minimum at 15 wt% PEG contents. Some suggstions were given for the spinning practice based on the melt rheological properties.