Molecular weight degradation stabilized polymeric compositions
AssigneeAllied Colloids Limited
InventorDavid Farrar
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Abstract
Polymeric compositions are stabilized against molecular weight degradation by the inclusion in the composition of an inhibitor which is preferably an ethylenically unsaturated compound. The invention is of particular value when the polymer is a polymer of (meth)acrylamide in which the amount of contamination of the polymer with free (meth)acrylamide monomer is extremely low and the inhibitor has LD.sub.50 above 400.
Claims24
A polymeric composition comprising a blend formed by mixing a preformed polymer of (meth)acrylamide and containing residual free (meth)acrylamide monomer with viscosity-degradation inhibitor, characterized in that the amount of free (meth)acrylamide monomer is below 0.1% by weight of the polymer and the LD.sub.50 of the inhibitor is above 400 mg/kg in rats and the oral inhibitor is an ethylenically unsaturated monomer which in the composition does not undergo any substantial reaction with said polymer.
A method of making a composition that comprises a blend of a viscosity-degradation inhibitor and a preformed polymer formed by polymerization of a water soluble ethylenically unsaturated monomer or monomer blend, characterized in that the inhibitor is an ethylenically unsaturated monomer which in the composition does not undergo any substantial reaction with said polymer and is added to the polymer either by imbibing an aqueous solution of the inhibitor into solid gel particles of the polymer before or after drying, or by mixing an aqueous solution of the inhibitor into a dispersion of the polymer in particulate form in a non-aqueous liquid.
A polymeric composition comprising a blend formed by mixing viscosity-degradation inhibitor with a preformed polymer formed from water soluble ethylenically unsaturated monomer or monomer blend characterized in that the inhibitor is an allylic monomer which in the composition does not undergo any substantial reaction with said polymer.
A polymeric composition comprising a blend formed by mixing viscosity-degradation inhibitor with a preformed polymer formed from water soluble ethylenically unsaturated monomer or monomer blend characterized in that the inhibitor is an ethylenically unsaturated monomer which in the composition does not undergo any substantial reaction with said polymer and the polymer is formed from monomers that consist essentially only of ethylenically unsaturated cationic or anionic monomers.
Dependencies are inferred from the claim text.