TB_Membranes_Processing_Guide

TechnicalBulletinSpecialtypolymerSProcessingGuideforPolymerMembranesOverthelastthirtyyears,theuseofporouspolymermembraneshasachievedasignificantpositionasacost-effectivemeansofnon-destructivelyseparatingcomponentsfromfluidmixtures.Membranetechnologypossessesanumberofattractivefeaturesinthatitcanbecarriedoutcontinuouslyundermildoperatingconditionsandrequireslittlespace.Itisalsoenvironmentallyfriendlyinthatenergyconsumptionisgenerallyverylowandfew,ifany,additivesarerequired.Itisbothacleaningandcleantechnology.Solvayofferstheindustry’sbroadestselectionofhigh-performancepolymersformembranes,including:•Solef®polyvinylidenefluoride(PVDF)•Halar®ethylenechlorotrifluoroethylene(ECTFE)•Udel®polysulfone(PSU)•Veradel®polyethersulfone(PESU)•Radel®polyphenylsulfone(PPSU)Thesematerialsareusedextensivelytomanufactureisotropicandanisotropicporoushollowfiberandflatsheetmembranesfortheentirerangeofthefiltrationspectrumfrommicrofiltration(MF)toreverseosmosis(RO).Dense-filmgaspurificationmembranesarealsoreadilypreparedwiththesematerials.ExcellentchemicalresistanceoveralargepHrange,hydrolyticstability,highstrengthandbroadagencycertificationsmakethesepolymerswell-suitedformembranesusedindemandingend-useenvironments.Typicalapplicationareasincludewaterpurification,wastewatertreatment,pharmaceuticalproduction,andbloodpurificationalongwithavarietyofindustrialprocessseparations,suchasfoodandbeverageprocessing,electropaintrecoveryandgasseparation.Manyoftheprocessesusedtomakeseparationmembranesrequiredissolvingthepolymerinasolvent.BecauseSolef®PVDF,Udel®PSU,Veradel®PESUandRadel®PPSUaresolubleinconventionalsolvents,theycanbesolventcastbytheDiffusion-InducedPhaseSeparation(DIPS)process.ThisprocessisalsoreferredtoasaNon-solvent-InducedPhaseSeparation(NIPS).TheDIPSprocessishighlysensitivetospinningprocessvariablesanddopesolutionvariability,makingitessentialtocloselycontrolboththemembranecastinganddopepreparationprocesses.Thiscanonlybeaccomplishedbyusinghigh-qualitypolymerswithminimallot-to-lotvariab