Synthesis And Composite Membrane Preparation Of Sulfonated Copoly(Phthalazinone Ether Sulfone)

Copoly(phthalazinone ether sulfone)(PPBES)(DHPZ:BP=6:4) is a good engineering plastic with high-glass transition temperature(273℃),good solubility,hydrophilicity,chemical resistance and mechanical properties.However,in order to make it more widely used, homogeneous sulfonation method was used in this research to develop its characters. Sulfonation is one of the effective methods to improve hydropobic character of copolymer. Sulfonated copoly(phthalazinone ether sulfone)(SPPBES) has excellent hydrophilicity and heat resistance to prepare nanofiltration membrane.With sulfuric acid as sulfonating agent,homogeneous sulfonation method was used to prepare SPPBESs(DHPZ:BP=6:4) with various sulfonation degree(SD).The effects of sulfonation process(the concentration of sulfuric acid,reaction temperature and time,and concentration ratio of PPBES/sulfuric acid) on SD of polymers were investigated.The SPPBES was characterized by FT-IR,¹H-NMR spectra and TGA.The water uptake,swelling ratio,oxidative resistance and solubility of SPPBES were also studied.The experimental results showed that SD increased as the increase of the concentration of sulfuric acid,reaction temperature and time,and decreased as the increase of concentration ratio of PPBES/sulfuric acid.SD of SPPBESs were controlled between 0.37～1.04.FT-IR and ¹H-NMR spectra confirmed that sulfuric acid groups were introduced into the polymer chain successfully. SPPBES is soluble in NMP,DMAc,DMSO,DMF and so on.It was found that water uptakes and swelling ratios of SPPBES increased as the increase of SD and temperature,and oxidative resistance decreased as SD and temperature increased.TGA indicated that SPPBES had good thermo-stability.SPPBES composite nanofiltration membrane was prepared with PPESK UF membrane as substrate and SPPBES as coating layer.Studies were focused on components of coating solution and preparation technics.According to experiment results,the composite membrane presented excellent properties when SD of SPPBES was 0.90,components of coating solution were:the polymer concentration was 2.0wt.%,mixed EGME,H₂O and ethanol(4:1:1) was the solvent,the addition of glycerin as cross-linking reagent was about 15wt.%,the addition of DMAc as aprotic solvent was 5wt.%,and the quantity of LiCl as inorganic additive was 1wt.%,and about thirty minutes heat-treating at 90℃.The water flux of the composite membrane was 66L/(m²Â·h),and 1g/L Na₂SO₄ solute rejection rate could be 86%when operation pressure was 1.0MPa at room temperature.