Synthesis Of Amphiphilic Material And Their Application In Modification Ultrafiltration Membranes

Polyethersulfone(PES) ultrafiltration membranes have good chemical stability, highstrength and broad pH range. So it has become one of the most widely used polymermembrane materials. However, one issue with PES is its high hydrophobicity, which severelylimits its long-term applicability. Hydrophilicity modification is helpful to change itshydrophobicity. In this paper, the amphiphilic copolymers PES-co-PEG was designed andsynthesized in order to improve the hydrophilicity of the PES membranes. Poly(ethyleneglycol)(PEG) is widely employed in the synthesis of amphiphilic copolymers viapolycondensation due to its low cost and hydrophilicity. Compared to the other amphiphiliccopolymers which have been reported, the copolymers PES-co-PEG, whose hydrophobicbackbone identical with the PES in molecular structures, guarantee the good compatibilitybetween PES and PES-co-PEG.In this paper, bisphenol S, dichloro-diphenyl sulfone and polyethylene glycol withdifferent molecular weight were used as the main material to synthesize a series of differentchain length of amphiphilic polymer PES-co-PEG. GPC,1HNMR, TG and FTIR wereconducted to characterize PES-co-PEG. The influence of reaction condition such as ratio ofthe reactants, solvent of polymerization reaction, reaction temperature and time, molecularweight of PEG were investigated. Results showed that the best reaction effect was usingPEG2000as reactants. The optimum technological conditions were as follows: usingtetramethylene sulfone as solvent, reaction temperature230C and reaction time at least8h.Then the copolymers PES-co-PEG were added to polyethersulfone casting solution forimproving membrane properties. Experiment was tested to research the modification effect ofamphiphilic polymer PES-co-PEG with different molecular weight PEG and the modificationeffect of different ratio of PES-co-PEG in the blend membranes. Differential scanningcalorimetry (DSC) was used to examine the mixing compatibility between the amphiphilicpolymer PES-co-PEG and PES. Scanning electron microscopy was used to observe the crosssection morphology of polyethersulfone and the blend ultrafiltration membranes. The contactangle meter was used to study the ultrafiltration membrane surface hydrophilicity. Andmultipurpose X-ray photoelectron spectroscopy was conducted to measure the surface elemental composition of ultrafiltration membranes. Static protein adsorption isothermexperiments and anti-pollution experiment were tested to compare the anti-pollution of thepure polyethersulfone membrane and blend membranes in the practical application.Finally, guangming milk was selected as pollutants to filter with pure polyethersulfonemembrane and blend membranes for a period of time. Then different cleaning methods wereused to clean the ultrafiltration membrane. In this way we could compare the effect ofdifferent cleaning methods and the cleaning effect of different ultrafiltration membranes.Besides, we need select the best cleaning method to compare the cleaning effect of themembranes blended with different amphiphilic polymer PES-co-PEG.