POLYVINYL PYRROLIDONE-GRAFTED COATINGS ON PREFORMED POLYMERS

摘要

2097088 9210533 PCTABS00013 In an improved method for producing a surface graft of a hydrophilic polymer upon a preformed solid or semi-solid polymer substrate having hydroperoxide groups along its surface, n-vinyl pyrrolidone is utilized as the surface-grafting monomer, the substrate is selected to be insoluble in n-vinyl pyrrolidone, and the polymerization is carried out in aqueous alkaline conditions utilizing a combination of metal salts to provide a variable valence metal ion in a reduced state capable of oxidizing to suppress homopolymerization of the monomer in the solution. When the substrate is at least partially soluble in the n-vinyl pyrrolidone, an ethylenically unsaturated monomer having a higher reactivity with the substrate than n-vinyl pyrrolidone is added to the alkaline polymerization solution as a ''seeding'' monomer. Addition of the ''seeding'' monomer results in a surface-grafted copolymer effectively externalized from the substrate.