The Preparation Of Polyethersulfone Hollow Fiber And Hydrophilic Modification

The aim of the present thesis centered on improving the hydrophilic property of thepolyethersulfone (PES) porous membranes which were prepared via phase inversionprocess. Two different treatments methods which are blend and thermal oxidationtreatment are used to modify the hydrophilicity of membranes. Then the structure andproperties of membranes were characterized to verify the efficiency.As a result, when the PES’s concentration is18%, the film surface has many pores.The fiber cross-sectional shape is finger holes and mesh structure. With the increasing ofthe concentration of PES, membrane’s porous structure reduces and film structure tends tocompact, the mechanical properties improve, the water flux decreases, the dynamic contactangle decreases. After the casting solution mixed with nano-SiO2, dynamic contact angle ofthe film is significantly reduced, mechanical strength, water flux, the initial decompositiontemperature and porosity increases with the increasing of nano-SiO2content. SEM testshows that with the addition of nano-SiO2the connectivity of membrane pores change forthe better. XRD and TG tests show that PES and SiO2has good compatibility. After castingsolution continue mixing PEG, SEM displays a lot of the membrane pores on themembrane’s surface, cross-section picture shows that the connectivity of membrane poresfurther improved, but the mechanical strength decreased, FT-IR test shows that hybridmembranes have no PEG residues.Thermal oxidation treating the fibers at a temperature of85~95℃with10%(NH4)2S2O8) solution keeps15min,30min,45min, modified PES hollow membranes. The resultsshow that the pure of PES after a30min treatment, membrane pore’s distribution and the size of the aperture become uniform, through the improvement of the membrane pores thewater flux becomes higher, the mechanical properties of the membrane maintain good,dynamic contact angle of films display the contact angle is less than80which proves betterhydrophilicity of films. PES/SiO2hybrid films processed15min treatment to achieve thebest mechanical properties. After30min treatment, the film excoriated the surface andappeared crack, FT-IR test shows a carbonyl group appeared at1723cm-1. PES/SiO2hybridfilm which added PEG processed thermal oxidation treatment, the membrane pores wereclosed, the membrane pore size was less than untreated film, after30min processing,dynamic contact angle of the membranes was less than40, indicating a goodhydrophilicity.