Study On Polyether Sulfone/modified Hydroxyapatite Mixed Matrix Membrane

Polyether sulfone(PES)is widely used for polymeric ultrafiltration and microfiltration membranes because of its toughness,good thermal resistance and chemical inertness.Hydroxyapatite(HAP)is an inorganic material and has good biocompatibility and biological activity.Besides,HAP has good adsorption to protein.However,all properties of HAP,especially the adsorption properties can be tailored by modifying the composition with ionic substitutions because the lattice parameter,crystallinity and grain size are changed.Then the surface of home-made doped-substituted hydroxyapatite nanoparticles were surface grafted with some organic polymer,which improve the surface properties,suspension stability and the compatibility between inorganic particles and polymer.In this study,strontium-substituted HAP nanocrystals were synthesized by ultrasonic method.The home-made Sr-HAP nanoparticles were surface grafted with acrylic acid(AAc)by low temperature plasma technology.The PES/Sr-HAP-AAc mixed matrix membranes(MMMs)were prepared by phase separation process.Polyvinylpyrrolidone(PVP)was used as pore-forming additive and dimethyl acetamide(DMAc)was used as solvent.The article contents are as follows:1.The effects of different synthesis conditions on structure and performance of Sr-HAP were studied by ultrasonic method.The chemical compound,crystalline phase,morphology,particle size distribution surface and area were characterized by FTIR,XRD,TEM,Particle Size Analyzer and BET.The effects of different Sr contents,reaction time,reaction temperature,PEG contents and sintering temperature on protein adsorption were studied.The results show that the best synthesis conditions for biggest adsorption capacity(81.4 mg BSA/g Sr50)to target protein are 50%Sr content,4h reaction time,60? reaction temperature,6%PEG contents and 60?sintering temperature.The shape of Sr50 is short rod-like.The length of Sr50 is about 30?40 nm and the diameter is about 10 nm.2.The effects of plasma processing conditions and graft conditions on structure and performance of Sr-HAP-AAc were studied by ultrasonic method.The chemical compound,grafting rate and suspension stability were characterized by FTIR,TG and Camera.The effects of different plasma treatment time,treatment power,treatment pressure,time exposed in the air,grafting time and grafting temperature on protein adsorption are studied.The results show that the best plasma treatment and grafting conditions are 9min treatment time,250W treatment power,60Pa treatment pressure,3min time exposed in the air,5h grafting time and 40? grafting temperature.The grafting rate of Sr-HAP-AAc reached 17.3%,the adsorption(95 mg BSA/g Sr-HAP-AAc)of Sr-HAP-AAc to target protein was improved obviously.3.The PES/Sr-HAP-AAc monolayer MMMs and double layer MMMs were prepared by phase separation process.The structure and properties of MMMs were also studied.The suitable conditions for preparing 0.22mm thickness monolayer MMMs are 60%Sr-HAP-AAc inorganic fillers,60%DMAc coagulation bath,15%PES,80%DMAc solvent and 5%PVP K90,the adsorption capacity to BSA was 53.3 mg BSA/g MMMs.The double layer MMMs were prepared by choosing 10%pure PES as upper casting solution and the 0.22mm thickness monolayer MMMs as lower casting solution,the adsorption was 48.6 mg BSA/g MMMs.The MMMs properties were investigated by scanning electron microscope(SEM)observations,pure water flux,the shrinkage rate,porosity and mean pore size.The adsorption rate and repetition adsorption ability of MMMa were discussed too.