Novel graft copolymers and process for the preparation thereof

Abstract

The present invention relates to novel graft copolymers and to a novel process for the preparation thereof. The polymeric compositions provided by the present invention comprise the reaction product of an ethylenically unsaturated monomer and a carboxylated cellulose ester having an acid number of at least about 5, an inherent viscosity of from about 0.01 to about 1.00 and wherein the anhydroglucose units thereof have ring substituents comprising by weight based on total polymer weight, of from about 0.05 to about 20% hydroxyl groups, from about 0.5 to about 44% acetyl groups, from 0 to about 54% butyryl groups, from 0 to about 47% propionyl groups, from about 0.4 to about 4.0% total carboxyl groups wherein from about 20% to about 100% of these carboxyl groups are non-saponifiable backbone, and wherein the material has a lactone level of from about 4.52.times.10.sup.-15 to about 6.13.times.10.sup.-4. Preferred carboxylated cellulose esters include carboxylated cellulose acetate, carboxylated cellulose acetate propionate, carboxylated cellulose acetate butyrate, and mixtures thereof. Preferred ethylenically unsaturated monomers include acrylic monomers, such as acrylic acid, methacrylic acid, acrylic acid esters, methacrylic acid esters, etc., acrylamides, methacrylamides, and vinyl monomers, such as vinyl aromatic compounds (e.g., styrene, divinylbenzene vinyltoluene, vinylnaphthalene, etc.), vinyl acetate, vinyl chloride, vinyl bromide, vinylidene chloride, vinylidene fluoride, tetrafluoroethylene, etc. The process of the present invention comprises reacting an ethylenically unsaturated monomer and a carboxylated cellulose ester at polymerization temperature (e.g., about 10.degree. to 250.degree. C.) in the substantial absence of an additional initiator.