Preparation,Characterization And Properties Of Polyethersulfone Microfiltration Modified Based On PEG Amphiphilic Copolymer

Polyethersulfone(PES)microfiltration membrane had been widely used due to its excellent mechanical strength and thermal stability.However,the intrinsic hydrophobicity of PES membrane made it easy to be contaminated during use,which affected the pure water flux of the microfiltration membrane.Surface modification of PES microfiltration membrane to improve its surface hydrophilicity had become the mainstream of current research.Among them,highly hydrophilic PEG had received extensive attention.In this paper,two novel amphiphilic copolymers based on PEG segments were designed and synthesized,and the synthesis process was discussed.Then they were used as polymer additives to modify PES microfiltration membranes,and the effects of two polymer additives on the morphology,hydrophilicity,antifouling property,mechanical properties and separation of metals of PES blended microfiltration membranes were studied.The specific research content is as follows:(1)The RAFT monomer B18C6Am containing methacrylamide and the RAFT monomer LAHEMA containing methacrylic acid were synthesized.The macromolecular chain transfer agent PPEGMA-CDB was obtained by RAFT polymerization,which used PEGMA as the monomer and CDB as the chain transfer agent.Then two amphiphilic block copolymers with different block ratios,poly(PPEGMA20-LAHEMA10-B 18C6Am10)and poly(PPEGMA20-LAHEMA15B18C6Am20)were synthesized using above materials,abbreviated as PELB1 and PELB2,respectively.The RAFT monomer,macromolecular chain transfer agent and block copolymer were characterized by NMR,FTIR.The self-assembly and response to potassium ions of two amphiphilic block copolymers were studied by TEM and UV=vis.In order to obtain a PES blended microfiltration membrane with balanced performance,PELB1 was selected as a polymer additive,and a PES/PELB blended microfiltration membrane was prepared by the immersion precipitation phase inversion method.The effect of the polymer additive PELB1 on the surface morphology,porosity,contact angle,pure water flux,BSA rejection,antifouling property,potassium ion adsorption and mechanical properties of PES blended microfiltration membranes were discussed by SEM,AFM,video optical contact angle measuring instrument,dead-end filter,conductivity meter and universal testing machine.It showed that the addition of the amphiphilic block copolymer PELB1 could reduce the contact angle of the PES blend membrane and incread the porosity and pore size,which increased the pure water flux and antifouling property of PES blended microfiltration membrane.At the same time,compared with pure PES membrane,PES blended microfiltration membrane also had better potassium ion adsorption and mechanical strength.This illustrates that the amphiphilic block copolymer PELB1 as a polymer additive could improve the hydrophilicity of PES microfiltration membranes,and provide a new way for the development of PES microfiltration membranes with better BSA antifouling and potassium ion removal.(2)Using PEGMA,LAHEMA and HAMA as monomers,CDB as chain transfer agent,three amphiphilic random copolymers with different degrees of polymerization were obtained by RAFT polymerization,named as poly(PEGMA3-LAHEMAisHAMA18),poly(PEGMA7-LAHEMA18-HAMA18),poly(PEGMA18-LAHEMA18HAMA18),abbreviated as PELH1,PELH2 and PELH3.Then use them as polymer additives to blend and modify PES microfiltration membranes.The results proved that compared with pure PES membrane,the pure water flux,antifouling performance,mechanical performance and rejection of gold nanoparticle of PES/PELH blended microfiltration membrane were significantly improved.This showed that the amphiphilic polymer PELH could simultaneously improve the hydrophilicity and mechanical properties of the PES microfiltration membrane,and give the PES membrane the ability to remove gold nanoparticles.