PPESK纺丝液相分离行为与气体分离膜结构性能的关系

以含二氮杂萘酮结构的聚芳醚砜酮(PPESK)为制膜材料纺制了中空纤维气体分离膜,通过浊点滴定和线性浊点关联式(LCP关系式)计算,对PPESK三元纺丝液体系的相分离行为进行了研究,得到了PPESK三元纺丝液体系相图的相平衡曲线;并由PPESK/N,N-二甲基乙酰胺(DMAc)/γ-丁内酯(GBL)和PPESK/DMAc/丙酸(PA)体系相分离数据计算了PPESK的θ溶剂中GBL和PA与DMAc的比例.结果表明,在PPESK/DMAc/PA和PPESK/DMAc/H2O体系中,浊点滴定实验得到的相平衡曲线与依据LCP关系式计算得到的相平衡曲线吻合;体系热力学性质稳定的纺丝液体系易于制备出结构致密、选择性高的中空纤维气体分离膜;非溶剂添加剂(NSA)/DMAc混合溶剂的θ组成对膜性能有至关重要的影响,NSA/DMAc高于θ组成时,膜性能发生突变,NSA/DMAc低于θ组成时,制得的膜性能良好;力学性能测试表明PPESK中空纤维膜具有良好的机械强度.

RELATIONSHIP BETWEEN THE PHASE SEPARATION OF PPESK SPINNING SOLUTION AND THE STRUCTURE AND PERFORMANCE OF MEMBRANE FOR GAS SEPARATION

Poly(phthalazinone ether sulfone ketone)(PPESK) hollow fiber membrane for gas separation was prepared by dry/wet phase inversion technique in water.T he cloud point titration method and the calculation based on linearized cloud po int (LCP) curve correlation were employed in the research of the phase separatio n of PPESK ternary spinning solution.In the PPESK/N,N_dimethylacetamide (DMAc )/g amma-butyrolactone (GBL) and PPESK/DMAc/propionic acid (PA) systems,the theta c om position of nonsolvent additive (NSA)/DMAc solvent mixture was determined accor ding to Elias's method.The results showed that the experimental cloud points and the calculated binodal lines based on LCP had a good agreement in the systems o f PPESK/DMAc/PA and PPESK/DMAc/water.From the thermodynamics stability of spinn ing solution and the final performance of hollow fiber membrane,conclusion coul d be drawn that higher the thermodynamics stability of spinning solution was,hi gher the gas selectivity of ultimate membrane was.The theta composition of NSA/ DMAc solvent mixture played a very important role in the membrane forming.When the NSA content of spinning solution was lower than its content at theta composi tion,the performance of membrane was excellent,but when the NSA content was hi gher than the theta composition,the performance of membrane droped sharply.The PPESK hollow fiber membranes had fine mechanical properties.