CO_2和环氧丙烷共聚过程流变特性

Process rheology characteristics of copolymerization for CO_2 and propylene oxide

CO2与环氧丙烷共聚体系涉及高压、气体及固体颗粒催化剂的分散,传统流变检测手段难以检测聚合过程中的聚合液黏度。文章通过搅拌电流法实验研究了此复杂多相体系的过程流变特性,发现其为变黏度过程,初期黏度很低,反应后期体系黏度达到10 Pa.s以上。聚合体系在中低压下过程黏度快速增大,高压下过程黏度变化较小,这是由于随压力升高体系体积增大,体系中CO2、环氧丙烷及催化剂浓度变化导致聚合物生成速率先加快后降低。

The traditional rheology detecting method is not applicable to the copolymerization system of CO2 and propylene oxide （ PO）, for it involves gas, high pressure and particle catalyst dispersion. The process rheology characteristics of this complex, multiphase system were experimentally studied by stirring electric current method. The results show that the viscosity is very low at the beginning, while at the end it is above 10 Pa · s. Under low and middle pressures, the viscosity increases rapidly, while under high pressure, the viscosity increases a little. This is attributed to two factors： with pressure increasing, the changes of the concentrations of CO2, PO and catalyst lead to a first uprising, then descending trend in the polymerization rate; the system volume keeps increasing with pressure increasing.