Synthesis Of Phenolphthalein Polyethersulfone Copolymers And Application In Water Treatment Membrane

Phenolphthalein polyethersulfone（PES-C）is a kind of high performance engineering,which has been widely used in aerospace,water treatment membrane,gas separation membrane,ion exchange membrane,reinforcing and toughening materials,conductive material matrix and other fields.However,PES-C is hydrophobic as a membrane material which results in membrane pollution in operation,reducing the separation efficiency and shortening the service life of membrane.Therefore,at the aim of improving the hydrophilicity of PES-C,two different types of carboxyl-phenolphthalein polyethersulfone（PESC-COOH）and amino-phenolphthalein polyethersulfone（PESC-NH₂）copolymers were prepared by introducing carboxyl group and amino group onto the side chain of PES-C,and were used in the study of water treatment membrane.1.A series of carboxylated phenolphthalein polyethersulfone copolymers（PESC-COOH）with different components were synthesized from phenolphthalein,phenolphthalein and difluoro diphenylsulfone by SN₂ polycondensation via adjusting the molar ratio of phenolphthalein to phenolphthalein.The polymer structure was determined by ¹H NMR and FT-IR.The introduction of carboxyl group improved the hydrophilicity of the polymer.Ultrafiltration membranes were prepared with PESC-COOH by the method of impregnation precipitation phase transformation.The effects of four factors including carboxyl content,polymer concentration,additive type and content on the ultrafiltration performance were investigated.When the carboxyl content was 30%and the polymer content was 15%,the pure water flux reached the maximum(399 L·m^-2·h^-1);the filtration effect of Tween80 was better than that of PEG1000.The BSA rejection of ultrafiltration membrane is not affected by the content of carboxyl group,polymer concentration,additive type.2.A series of aminated phenolphthalein polyethersulfone copolymers（PESC-NH₂）with different components were synthesized from phenolphthalein,5,5’-diamino-4,4’-dih-ydroxydiphenylsulfone and difluorodiphenylsulfone by SN₂ polycondensation via adjusting the molar ratio of phenolphthalein to 5,5’-diamino-4,4’-dih-ydroxydiphenylsulfone.The polymer structure was confirmed by ¹H NMR and FT-IR.The introduction of carboxyl group improved the hydrophilicity of the polymer.Ultrafiltration membranes were prepared with PESC-NH₂ through the method of impregnation precipitation phase transformation.The effects of four factors including carboxyl content,polymer concentration,additive type and content on the ultrafiltration performance were investigated.When the amino content was 40%and the polymer concentration was 15%,the pure water flux reached the maximum,and the filtering effect of Tween80 is better than that of PEG1000.