Chemically joined, phase separated self-cured hydrophilic thermoplastic graft copolymers and their preparation

Claim 1

A chemically joined, phase separated self-cured hydrophilic thermoplastic graft copolymer of: 1. at least one copolymerizable normally hydrophobic macromolecular monomer having a substantially uniform molecular weight distribution, and 2. at least one hydrophilic (water-soluble) copolymerizable comonomer or compound rendered hydrophilic forming the polymeric backbone of said copolymer, said copolymerizable normally hydrophobic macromolecular monomer forming linear polymeric sidechains of said graft copolymer, wherein: a. the polymeric backbone of the graft copolymer is comprised of polymerized units of said copolymerizable comonomers, wherein the copolymerizable comonomers are selected from the group consisting of hydroxyalkyl and hydroxyalkoxyalkyl esters of acrylic and methacrylic acids, N-hydroxyalkyl and N,N-bis-hydroxyalkyl amides of acrylic and methacrylic acids, vinyl esters of monocarboxylic acids which are rendered hydrophilic by hydrolysis of said vinyl esters subsequent to copolymerization, N-vinyl pyrrolidone, N-vinyl piperidone, N-acrylylpyrrolidone, N-acrylylpiperidine, N-acrylylmorpholine, quaternary ammonium salts of ethylenically unsaturated compounds, and mixtures thereof; b. the linear polymeric sidechains of the graft copolymer consist essentially of a polymerized hydrophobic macromolecular monomer, said hydrophobic macromolecular monomer comprising a linear polymer or copolymer having a molecular weight of at least about 2,000 and having a substantially uniform molecular weight distribution, such that its ratio of Mw/Mn is not substantially above about 1.1, said macromolecular monomer being further characterized as having no more than one copolymerizable moiety per linear polymer or copolymer chain, said copolymerization occurring between the copolymerizable end group of said hydrophobic macromolecular monomer and said copolymerizable hydrophilic comonomer; and c. the linear polymeric sidechains of the graft copolymer which are copolymerized into the copolymeric backbone are separated by at least about 20 uninterrupted recurring monomeric units of said hydrophilic polymeric backbone, the distribution of the sidechains along the backbone and the copolymerization being controlled by the reactivity ratio of the copolymerizable end groups on said hydrophobic macromolecular monomer and said copolymerizable hydrophilic comonomer.