Preparation And Improvement Anti-Fouling Property And Blood Compatibility Of Polyethersulfone Ultrafiltration Membrane By Blending Comb-Like Amphiphilic Copolymer SMA-MPEG

Polyethersulfone (PES) ultrafiltration (UF) membrane has become one of the most widely used polymer membrane materials due to its good chemical stability, high mechanical strength, good heat resistance and wide pH range. While its further development and application were restricted by its hydrophibicity,. In order to improve its anti-fouling ability and blood compatibility, comb-like amphiphilic copolymer (SMA-MPEG) was used as the modification agent. SMA-MPEG was synthesized by esterification reaction of styrene maleic anhydride (SMA) and methoxy polyethylene glycol (MPEG). PES membranes were prepared by an immersion precipitation phase inversion method using DMAc as solvent and SMA-MPEG as hydrophilic modification agent.Firstly, the effect of SMA-MPEG750 amount added into the casting solution on the structure and properties of PES UF membrane was investigated. The membrane surface was characterized by Attenuated total reflection Fourier transform infrared spectrometer. The results confirmed that the amphiphilic copolymer had embedded into PES membrane. Scanning electron microscope observation indicated that the structure of modified PES membrane did not change obviously. The water contact angle (CA) test indicated that the hydrophilicity of the modified membrane increased with the content of amphiphilic copolymer modifier in the casting solution increasing. The ultrafiltration performance of the membranes was investigated by dynamic filtration bovine serum albumin (BSA)) and extracellular polymeric secretions (EPS) solution. The permeation flux and anti-fouling properties of modified membrane were improved obviously. And the membrane modified with 2 wt% SMA-MPEG750 displayed the highest permeation flux and the best antifouling properties. The blood compatibility of the membranes was also evaluated by protein adsorption, platelet adhesion and hemolysis test. The results revealed that the modified membranes had good blood compatibility featured by the lower platelet adhesion, protein adsorption and a little hemolysis.Secondly, the modification effect of SMA-MPEG with different hydrophilic MPEG chain length on the PES/SMA-MPEG blending membrane was further researched. MPEG with different molecular weight 350,500,750 and 1000 were chosen to graft onto SMA backbone to synthesize four amphiphilic copolymers. Four amphiphilic copolymers were blended with PES respectively under the same condition to prepare PES/SMA-MPEG modified membranes. The results suggested that some amphiphilic copolymer molecules acted as pore-forming agent and some amphiphilic copolymer molecules acted as hydrophilic modification agent in the immersion precipitation phase inversion process. Meanwhile, the longer the hydrophilic MPEG chain length was, the higher the water flux of modified membranes would be. However, PES membranes modified with SMA-MPEG750 presented the best hydrophilicity, anti-fouling ability and blood compatibility due to the amount of amphiphilic copolymer enriched on membrane surface was relative more and the hydrophilic chain in copolymer was relatively longer compared with other amphiphilic copolymer molecules.