反应挤出过程中PET扩链反应的研究

Study of the chain extension of PET during reactive extrusion

分别加入羧基加成型的双噁唑啉(BOZ)和羟基加成型的均苯四甲酸酐(PMDA)为扩链剂,考察了反应挤出前后PET特性黏度([η])和羧基值的变化情况。实验结果表明:BOZ的扩链效果不明显;PMDA能较大程度地提高PET的[η],但产品羧基值较高;BOZ和PMDA联用可得到高[η]低羧基值的产品,扩链效果最佳。当挤出机工艺条件为:反应段温度260℃、螺杆转速45 r/min、反应段压力1 kPa、BOZ和PMDA质量分数均为0.2%时,可得到[η]为0.90 dL/g,羧基值为25 mol/t的PET产品。

The chang of [ η] and carboxyl value of PET pre-and post-reactive extrusion process was studied carefully based on the feeding of 2,2-Bis （2-oxazoline） （BOZ） and Pyromellitic dianhydride （PMDA） as chain extenders. The experiments results showed that the chain extension effects of BOZ was not obvious, while PMDA can increase the [ η] of PET to a great extent, but the carboxyl value of PET was high. The PET products with high [ η] and low carboxyl value can be obtained by the combinated using of BOZ and PMDA. The chain extension results were optimum. The PET products with [ η] （0.90 dL/g） and carboxyl value （25 mol/t） can be obtained at the reactive condition as follows：the reaction stage temperature at 260, the screw rotation speed is 45 r/min, the reaction stage pressure is 1 kPa, the mass fraction of both BOZ and PMDA is 0.2%.