Study On Antifouling Performance Of Polysulfone With Low Temperature Plasma Surface Modification And Vapor Phase Grafting Polymerization

In order to understand the antifouling performance of low temperature plasma surface modified and vapor phase grafting polymerized polysulfone(PSF) ultrafiltration membrane in air atmosphere. The effect of the modifying conditions and surface properties were characterized by the contact angle measurement, roughness, pore size, specific surface area and surface morphology. Antifouling experiment was carried out with bovine serum albumin used as proteinlike substances. Antifouling properties of PSF such as permeability, contamination rate, and flux recovery rate were evaluated.Results show that wettability of modified PSF surface is changed. When the optimal discharge power is 8W and the optimum processing time is 30 s, the water contact angle decreases from 69° to 25°. On this basis, different grafting systems are studied and compared. And the optimum grafting polymerization is found that is the combination of plasma graft-to system and vapor phase heterogeneous polymerization system(hereafter referred to as plasma- vapor system). By means of plasma- vapor system, the water contact angle decreases to 20°. Hydrophilicity is further improved.The results of antifouling experiment show that the permeability and antifouling property is improved obviously.From the study of the mechanism of plasma, it is found that there is a positive correlation between the reaction performance of free radicals and discharge power. However, if the average kinetic energy of active particles is too strong, the phenomenon of etch will happen. When the discharge power is 8 w, the concentration and activity of free radicals is medium. And the phenomenon of etch is reduced. So it is possible to provide more oxygen free radicals for grafting polymerization.According to the characterization of membrane surface properties, the results showed that the roughness and specific surface area decreases with discharge time. The pore size increases with discharge time. In addition, there is no correlation between discharge power and roughness.