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SYNOPSISUltrafiltration membranes were prepared from mixtures of poly (phenyl sulfone) ( Radel R5000) and poly(viny1 pyrrolidone) (PVP) dissolved in 1-methyl-2-pyrrolidinone (NMP) .The effects of the casting solution composition on membrane performance and morphology are presented. Radel R5000 membranes showed higher productivity for a given pore size when compared to other polysulfone membranes. The biphenyl group in Radel R5000 makes it more rigid in comparison to other polysulfones. This may result in more ordered packing, which resulted in the higher productivities and smaller pore sizes observed in the membranes.

SYNOPSISPolysulfone membranes were modified heterogeneously by lithiation, using n -butyllithium and low concentrations of tetrahydrofuran (THF). The effects of various conditions of reactant concentration, temperature, and time were determined quantitatively. The degree of substitution was measured by XPS and FTIR, using the carbonyl absorption band of lithium-activated membranes that had been converted to ones containing acyl fluoride substituents. The optimum conditions for membrane functionalization were 0.2M n-butyllithium in hexane at room temperature. The reaction rate increased substantially in the presence of 2% THF. The surface-lithiated membranes can be derivatized, potentially with a wide variety of functional groups.

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