Polyvinyl pyrrolidone-grafted coatings on preformed polymers
First Claim
1. A process for producing a graft copolymer which comprises the graft polymerization of ethylenically unsaturated compounds, in solution, with a substantially insoluble preformed solid or semi-solid polymeric substrate having hydroperoxide groups along the polymer chains thereof, in the presence of a variable valence metal ion in a reduced state capable of oxidizing to suppress homopolymerization of the ethylenically unsaturated monomer in said solution, wherein the improvement comprises:
- utilizing n-vinyl pyrrolidone as the ethylenically unsaturated monomer, selected a substrate insoluble in n-vinyl pyrrolidone, carrying out the polymerization under aqueous alkaline conditions, and utilizing a combination of at least two metal salts to provide the variable valence metal ions, said at least two metal salts being sufficiently soluble under alkaline conditions in aqueous solution to inhibit homopolymerization of the ethylenically unsaturated monomer.
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Abstract
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.
32 Citations
27 Claims
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1. A process for producing a graft copolymer which comprises the graft polymerization of ethylenically unsaturated compounds, in solution, with a substantially insoluble preformed solid or semi-solid polymeric substrate having hydroperoxide groups along the polymer chains thereof, in the presence of a variable valence metal ion in a reduced state capable of oxidizing to suppress homopolymerization of the ethylenically unsaturated monomer in said solution, wherein the improvement comprises:
utilizing n-vinyl pyrrolidone as the ethylenically unsaturated monomer, selected a substrate insoluble in n-vinyl pyrrolidone, carrying out the polymerization under aqueous alkaline conditions, and utilizing a combination of at least two metal salts to provide the variable valence metal ions, said at least two metal salts being sufficiently soluble under alkaline conditions in aqueous solution to inhibit homopolymerization of the ethylenically unsaturated monomer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A process for producing a graft copolymer which comprises the graft polymerization of ethylenically unsaturated compounds, in aqueous solution, with a preformed solid or semi-solid polymeric substrate having hydroperoxide groups along the polymer chains thereof, in the presence of a variable valence metal ion in a reduced state capable of oxidizing to suppress homopolymerization of the ethylenically unsaturated monomer in said solution, wherein the improvement comprises:
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utilizing n-vinyl pyrrolidone as the ethylenically unsaturated monomer; carrying out the polymerization under alkaline conditions in aqueous solution in the presence of a seed ethylenically unsaturated monomer having a higher reactivity with the substrate than n-vinyl pyrrolidone the monomer being present in an amount sufficient to effect surface grafting of N-vinyl pyrrolidone and prohibit graft internal reaction; and utilizing a combination of at least two metal salts to provide the variable valence metal ion, the metal salts being sufficiently soluble under alkaline conditions in aqueous solution to inhibit homopolymerization of the ethylenically unsaturated monomer. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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Specification