Compatibility of Polyvinyl Chloride- Polyvinyl Alcohol and Structure and Properties of Their Composite Porous Membranes

Polyvinyl chloride -polyvinyl alcohol ( PVC -PVA ) composite porous membranes were prepared by solution filming , the compatibility of PVC -PVA was analyzed from the perspective of mixing enthalpy and inter -molecular interactions. The pore morphology , hydrophilicity , filtration performance and mechanical properties of the composite porous membranes were analyzed by scanning electron microscopy ( SEM ), contact angle measurement and plate ultrafiltration membrane test , etc. The research results show that hydrogen bonds and dipole interactions could be formed among macromolecules in PVC -PVA composite system , the mixing enthalpy show a trend of first increasing and then decreasing with the increase of the mass fraction of PVA in polymers , and PVC -PVA is generally partially compatible. Compared with pure PVC membrane , the " finger like pore " feature of the cross -section of PVC -PVA composite membrane became weaker , while the " sponge pore " feature became apparent , and the pure water flux of the composite prous membrane was increased , the pollution resistance was improved , and the mechanical toughness was enhanced. When the mass fraction of PVA in polymers was 9% , the pure water flux of the composite membrane was about 4 times that of pure PVC membrane , the retention rate of PEG100000 was 80% , the strength was 3.5 MPa , and the elongation at break was 26% , the composite has a good application prospect in the field of water treatment.