PREPARATION AND CHARACTERIZATION OF POROUS POLYSULFONE MEMBRANES WITHSPACER-BONDED N-CONTAINING GROUPS

Ultrafiltration membranes were prepared from epoxidized polysulfone by the conventional phase separation procedure. For epoxidizing, the pol ymer was first lithiated and a reaction followed with glycidyl-4-oxohe xylether providing an eight atomic spacer. The reaction of the epoxy g roup with N-containing substituents was performed heterogeneously usin g the ready membranes. The stability of the substituted membranes is v isible by the fact that they are reacted under reflux conditions for 2 4 h. The reagents were trimethyl amine, diethylamine, n-butyl amine, a nd tauric acid. Thus, positively charged, negatively charged, and neut ral membranes were obtained. The membranes were characterized via ultr afiltration using dextran solution as well as human albumin solutions. In addition, the streaming potential was measured in the presence and absence of the protein. By these measurements the obviously neutral m embranes were surprisingly identified to be positively charged. This i s related to subsequent reactions of the spacer-bonded epoxy groups wi th the amino groups. (C) 1995 John Wiley and Sons, Inc.