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AssigneeAmerican Hospital Supply Corporation
InventorsKenneth G. Mayhan, Robert A. Janssen, William J. Bertrand
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A process for modifying the surface characteristics of a pre-formed polymeric substrate to impart hydrophilicity, hydrophobicity, or other desired properties thereto, by peroxidizing the surface of the substrate and then allowing the active sites along the polymer chains to generate free radicals which induce graft polymerization of a suitable ethylenic monomer (or other ethylenically-unsaturated compound) onto the surface of the substrate is described. Such graft copolymerization is undertaken in the presence of variable valence metal ions in a reduced state under acidic conditions and at selected reaction times and relatively low temperatures, and in the presence of squarate ions (diketocyclobutenediol) to control the physical characteristics of the surface graft and to restore the metal ions to their lower valence state without at the same time producing deleterious by-products.
A process for producing a graft copolymer which comprises the graft polymerization of an ethylenically-unsaturated compound, in solution, with a substantially insoluble pre-formed solid or semi-solid polymeric substrate having peroxide groups, including hydroperoxide groups, along the polymer chains thereof, wherein the improvement comprises carrying out said polymerization in the presence of a variable valence metal ion in a reduced state capable of oxidizing to convert free hydroxyl radical to hydroxyl ion and thereby suppress homopolymerization of said monomer in said solution, said solution also containing squaric acid (diketocyclobutenediol and its ionized form) in a concentration sufficient to reduce said metal ion from its oxidized state and of complexing with said ion in its reduced state.
A process for producing a graft copolymer which comprises the graft polymerization of a water-soluble ethylenically-unsaturated compound, in aqueous solution, with a substantially insoluble pre-formed solid or semi-solid polymeric substrate having peroxide groups, including hydroperoxide groups, along the polymer chains thereof, wherein the improvement comprises carrying out said polymerization in the presence of a variable valence metal ion in a reduced state capable of oxidizing to convert free hydroxyl radical to hydroxyl ion and thereby suppress homopolymerization of said monomer in said solution, said variable valence metal ion being selected from the group consisting of the ions of cobalt, manganese, iron, tin, molybdenum, and indium in their reduced states, said solution also containing squaric acid in a concentration sufficient to reduce said metal ion from its oxidized state and of complexing with said ion in its reduced state.
Dependencies are inferred from the claim text.