添加剂PEG对CPVC/PVB共混膜性能的影响

Effects of additive PEG on the properties of CPVC/PVB blended membranes

探讨了聚乙二醇(PEG)分子量(400、600、1000、1500、2000、4000和6000)对氯化聚乙烯/聚乙烯醇缩丁醛(CPVC/PVB)超滤膜微观结构及其性能(纯水通量、截留率、机械强度和耐污染性能)的影响。结果表明:PEG分子量小于6000时,CPVC/PVB共混膜断面的指状大孔被疏松的多孔结构取代,PEG达到6000时,膜断面出现指状大孔结构,其微观结构与未加添加剂时的微观结构基本一致;PEG分子量为400和600时,CPVC/PVB共混膜表面为多孔结构,随着PEG分子量的增大,膜表面趋于致密。添加不同分子量PEG,均能使CPVC/PVB共混膜的水通量和耐污染性能大幅提升,其中PEG4000和PEG6000提高最多,但膜的截留率和机械性能略有下降。经过比较PEG6000作为添加剂,CPVC/PVB共混膜的性能较优。

Effect of additive PEG molecular weights on the microstructures and properties of CPVC/PVB blended membranes was discussed in this paper. It was found that the finger-like macrovoids structure in the microstructures of CPVC/PVB blended membranes cross section was replaced by porosity microstructure when the molecular weight was less than 6000. The finger-like macrovoids structure reappeared when the molecular weight was up to 6000 and the cross section microstructure was close to that of CPVC/PVB blended membranes which were free of additive. The microstructure of membrane surface was porosity structure when the molecular weight was 400 and 600, respectively. With the increase of molecular weight, the microstructure of membrane surface tended to be dense. All the PEGs increased the permeability and antifouling properties of CPVC/PVB blended membranes remarkably. Among them PEG 4000 and PEG 6000 increased much more. However, the retention and mechanical property declined a little. PEG 6000 as an additive could make CPVC/PVB blended membranes have better membrane properties.