Preparation And Hydrophilic Modification Of Poly(Ether Sulfone) Microporous Membrane Via Phase Separation Method

In this work, Poly(ether sulfone)(PES),which is widely used polymer with excellent physical and chemical properties,was used as membrane material.Nonsolvent induced phase separation (NIPS) and thermally induced phase separation(TIPS)methods were employed to prepare PES microporous membrane.Meanwhile, amphiphilic brush-like copolymer P(MMA-γ-PEGMA)was used as additive to modify the hydrophilicity ofthe PES membrane. The structure and performance of the membrane were characterized in order to verify the influence of different conditions on the preparing process.In this paper, we mainly focused on three research projects:Firstly, sulfone A and ester B were used as diluent mixture, the phase behavior of the ternary system of PES/sulfone A/ester B was determined.Then. PES flat membrane was achieved via combined TIPS and NIPS, along with DMAc as the coagulation bath. Secondly, on the basis of PES flat membrane preparation, we obtained PES hollow fiber membrane with coagulation bath containing sulfone A in it. The effects of sulfone A and ester B ratio in the diluent mixture,sulfone A concentration in the coagulation bath as well as the temperature of coagulation bath,on the structure and performance of membrane have been investigated.Furthermore, because of the hydrophobicity of PES.amphiphilic brush-like copolymer P (MMA-γ-PEGMA)was synthesized by radical copolymerization between MMAand PEGMA.The effect of amphiphilic copolymer on the surface hydrophilicity of PES membrane was also studied.Based on the research in this paper, we can draw four major conclusions as follows:(1) The ratio of sulfone A and ester B in the diluent mixture had significant influence on the miscibility of PES.and the critical ratio of these two solvents is4:3.The compatibility of PES increased as the increase of the content of sulfone A in the diluent mixture.(2)The mechanism of the phase separation could be changed by the variation of coagulation bath temperature in the experiment.At temperature upon cloud point. NIPS occurred only;on the contrary, both NIPS and TIPS would happen, if the temperature was below cloud point.(3)InNIPS,the composition of diluent mixture and coagulation bath affected the exchange rate of solvent and nonsolvent in the system essentially. While in TIPS,composition of diluent mixture mainly influenced the compatibility of PES.and the change of coagulation bath altered polymer concentration on the interphase.(4) The introduction of amphiphilic brush-like copolymer P (MMA-γ-PEGMA)remarkably improved the surface hydrophilicity of PES hollow fiber membrane.An amount of20wt%copolymer-added generated a decrease of water contact angle to below40°after40seconds,and the inside-out and outside-in water flux was716.6L/(m2·h) and633.7L/(m2·h) respectively.