Polyurethane Blend Membranes Of The Separation Performance

The studies on the Polyurethane/Polyacrylonitrile(PU/PAN),PU/Cellose acetate (PU/CA ) , PU/Polysulfone (PU/PS ) blendmembrane and their separation properties were fulfilled in thispaper.The studies on the compatibility of blend systems were carriedout firstly. The resu1ts showed that the PU/PAN, PU/CA, PU/PSblend systems were partially compatible and the compatibility wasrelated to the composition of systems. The compatibility of systemsturned into bad with the increase of PAN,CA and PS weight contentand the addition of Polyethylene glycol (PEG).The relationship between composition of the casting solution,membrane preparation technology together with post-treatmentprocess and the performance and structure of flat membrane wasstudied. The resuIts showed that the water flux decreased andretention increased with the increase of the total concentration ofblend system. The water flux increased and retention decreased withthe increase of PAN,CA,PS content in PU/PAN,PU/CA and PU/PSblend membrane. This is also true with the increase of PEG content.The water flux decreased and retention increased with the increaseof the heat treatment temperature of PU/PAN and PU/PS blendmembrane. But the water flux of PU/CA blend membrane got themaximum with the heat treatment temperature of 60℃ anddecreased rapidly with the heat treatment temperature of l00℃.The formation of the interfacial micro-void and its influence tothe membrane properties were studied. The results showed that theinterfacial micro-void was caused by interfacial separation and thecontent and the size were related to the compatibility of blendsystems. The content of interfacial micro-void was high bychoosing appropriate b1end system and through particularpost-treatment process. In particular conditions, the effect ofmembranes caused by the interfacial micro-void was more important． The pressure memory e蚀ct andthe temperature memory effectof the blend membranes were also studied．The results showed thatthe memory effect of＊the water flux of＊the blendmembranes wastightly related to tile shape memory function ofPU and the strtlctureofinterfaclal micro－void．The accuracy ofthepressure memoryeffect and tile temperature memory effect of the blend membranesturffed worse wltll tile decrease of the content of PU and theInterfaclal micro－void In blend systems． Withthebase offlatmembrane study,the blend hollownbermembranes(PVDF／PU,CA／PU)were successfully fabricated．Andtheir structure andpropertywere analyzedhere．The results showedthattlle properties con刊rmedto the lat membrane．The water luxofthePVDF／PU,CA／PUmembranes Increasedandretentlondecreased wltll tile lllcrease of the content of PU．The water fluxIncreased and retention decreased with the addition of PEG． The utlllzatlon In the treatment ofphosphorlzed water ofPUblend membranes was studied．The results showed that thepercentage of＊thetage removal ofT－P reached 99％and got good effectby adopting the 'nethod of chemical and membranous treatment.