Preparation and Characterization of Polysulfone-PolyvinylPyrrollindone based membranes

Desalination,70(1966)265-275265ElsevierSciencePublishersB.V.,Amsterdam-PrintedinTheNetherlandsPREPARATIONANDCHARACTERIZATIONOFPOLYSULFONE-POLYVINYLPYRROLIDONEBASEDMEMBRANES.S.MUNARIl,A.BOTTINOl,G.CAPANNELL12,P.MORETTIlandP.PETITBONI1InstituteofIndustrialChemistry,UniversityofGenoa,CorsoEuropa30,I-16132Genoa(Italy)2InstituteofIndustrialChemistry,UniversityofMessina,ContradaPapardo,I-98100Messina(Italy)SUMMARYMicroporouspolysulfonemembraneswerepreparedfromcastingsolutionsofpolysulfone,solventandpolyvinylpyrrolidoneasadditive.Themembraneswerecharacterizedbyscanning-electronmicroscopeobservations,porositymeasurementsandultrafiltrationtests.Theeffectofuolyvinvlpvrrolidoneanditsmolecularweightontheviscosityofthecastingsolutionsandthepropertiesofthemembranesisdiscussed.INTRODUCTIONBecauseofitschemicalresistanceandthermalstabilitypolysulfone(PS)isextensivelyusedformembranepreparation[1,2].PSmembranesarepreparedbyphaseinversionprocess.N,N-dimethylacetamide,N,N-dimethylformamide,dimethylsulfoxideandN-methyl-2-pyrrolidonearegenerallyusedassolvents.Duetothelowmolecularmassofthepolymer,PSsolutionsarecharacterizedbylowviscositiesandconsequently,aredifficulttocast.Toovercomethisproblemitiscommonpracticetoaddpolyvinylpyrrolidone(PVP)tothePSsolution[1,3-81.ThishydrosolublepolymerdissolvesinthesolventsmentionedaboveandiscompatiblewithPS[3].InspiteofthewideuseofPVPasadditive,fewpapers[3,5-71supplyinformationontheinfluenceofconcentrationandmolecularmassonthepropertiesofthemembranes.Wehaverecentlystartedaresearchtoincreaseknowledgeonthissubject.Inthispaperthestructure,ultrafiltrationperformanceandporosityofPS/PVPbasedmembranesarediscussedwithrespecttothebothPS/PVPratiointhesolutionandthemolecularmassoftheadditive.EXPERIMENTALMaterialandsolutionsPolysulfone(UDELP-3500)wassuppliedbyAmocoChemicals.Polyvinyl-pyrrolidonewithnominalaveragemolecularmass(Mw)of25,000(25K)and750,000(750K),respectively,wereobtainedbyServa.ReagentgradeN,N-OOll-9164/88/$03.5001968ElsevierSciencePublishersB.V.266dime