Preparation of cation-exchange fibers with high protein-binding capacities by pre-irradiation induced emulsion graft polymerization

To raise the adsorption capacity of cation-exchange fiber for protein, two methods of pre-irradiation grafting using either a solution or an emulsion of glycidyl methacrylate (GMA) were compared. The epoxy group of poly-GMA grafted onto a commercially available 6-nylon fiber was converted into a sulfonic acid group by reaction with sodium sulfite. Lysozyme solution (pH 9.0) was passed through a bed charged with one of the cation-exchange fibers at a space velocity of 60 h⁻¹. At a degree of GMA grafting of 81-87%, the 10% dynamic binding capacity of the bed charged with the fiber prepared by the emulsion grafting was four-fold that of the bed prepared by the solution grafting. The graft chain formed near the periphery of the fiber by the emulsion grafting is considered to contribute to the rapid capture of protein.