| abstract |
The present invention provides crosslinked ampholytic copolymers that are highly absorbent to aqueous electrolyte solutions. The polymers of the present invention comprises polymers formed by the copolymerization of an effective amount of each of the following components to produce a polymer which is highly absorbent to aqueous electrolyte solutions: n (a) an ampholytic ion pair monomer comprising n (i) an ammonium cation 2-methacryloyloxyethyltrimethylammonium and n ii a sulfonate anion selected form the group consisting of 2-acrylamido-2-methylpropane sulfonate, 2-methacryloyloxethane sulfonate, vinyl sulfonate, styrene sulfonate and combinations of two or more thereof; n (b) at least one comonomer selected from the group consisting of acrylamide, methacrylamide, acrylonitrile, acrylic acid, methacrylic acid, alkali salts of acrylic acid, alkali salts of methacrylic acid, 2-methacryloyloxyethyltrimethylamine, 2-acrylamido-2-methylpropane sulfonic acid, alkali salts of 2-acrylamido-2-methylpropane sulfonic acid, akali salts of 2-acrylamido-2-methylpropane sulfonic acid, 2-methacryloyloxyethane sulfonic acid, alkali salts of 2-methacryloyloxyethane sulfonic acid, N-vinyl-2-pyrrolidone and combinations of two or more thereof; and n (c) at least one crosslinking agent which has at least two polymerizable olefinic functionalities wherein the olefinic functionalities are suitable for crosslinking. n The invention also provides a method of using the polymers of the present invention for absorbing aqueous electrolyte solutions comprising the step of contacting the polymers of the present invention with the aqueous electrolyte solution. |