FUNCTIONALIZED POLYSULFONE MEMBRANES BY HETEROGENEOUS LITHIATION

Polysulfone membranes were modified heterogeneously by lithiation, usi ng 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 w as measured by XPS and FTIR, using the carbonyl absorption band of lit hium-activated membranes that had been converted to ones containing ac yl fluoride substituents. The optimum conditions for membrane function alization were 0.2 M 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 wid e variety of functional groups.