AMINO-ACID ADDITION TO EPOXY-GROUP-CONTAINING POLYMER-CHAIN GRAFTED ONTO A POROUS MEMBRANE

By radiation-induced graft polymerization and subsequent chemical modi fication, an L-amino acid was appended onto a porous polyethylene (PE) membrane of a hollow-fiber form to prepare the pseudoaffinity porous membrane for membrane chromatography. First, an epoxy-group-containing vinyl monomer, glycidyl methacrylate (GMA), was grafted onto the PE m embrane. Second, ring opening of the produced epoxy group was induced in the presence of ten different L-amino acids. The ligand density of neutral L-amino acids of the resultant membrane ranged from 0.80 to 0. 96 mmol per g of the membrane, which corresponded to the molar convers ion due to L-amino acid addition to the epoxy group from 23 to 33%. By contrast, acidic and basic L-amino acids opened the epoxy ring at a l ower conversion of 0.62-6.3%. Regardless of the conversion, the aceton e flux of the membranes increased by 20% compared to that of the GMA-g rafted membrane, because an alkaline treatment induced swelling of the poly-GMA chains grafted onto the PE matrix.