The United States of America As Represented by the Secretary of

Edward I Stout

William McKee Doane

George F Fanta

Baruch S Shasha

Starch-based superabsorbents are extended by blending with highly modified, low molecular weight starches. The dextrinized starches synergistically interact with the superabsorbents thereby permitting dilution without a commensurate reduction in the water absorbency. While the principal utility of the blends is the absorption of aqueous fluids, when hydrated they yield soft, smooth gels useful as high-quality thickening agents.

Modified starches as extenders for absorbent polymers

Absorbent compositions comprising graft copolymers of starch are prepared by a simplified method of synthesis. By using a mixture of a nonionic acrylic monomer and an anionic sulfonic acid-substituted acrylic monomer, highly absorbent compositions are prepared without the need for an alkaline saponification step. These compositions are also characterized by their ability to absorb large amounts of aqueous fluids under highly acidic conditions.

Highly absorbent polyhydroxy polymer graft copolymers without

Absorbent compositions comprising graft copolymers of acrylonitrile and starch, or related polyhydroxy polymers, are prepared by improved methods of synthesis. Mixing the acrylonitrile with selected water-soluble acrylic comonomers enables unexpected improvements including reduction of the saponification time, total elimination of the base-saponification step, elimination of the starch gelatinization step, preparation of products which absorb large amounts of aqueous fluids under highly acidic conditions, and preparation of products which absorb over 5000 times their weight of deionized water.

Highly absorbent graft copolymers of polyhydroxy polymers,

A simple and selective technique for the oxidation of thiols resulted in high yields of the corresponding disulfides. The reaction is tailored so that all byproducts are either volatile or insoluble and the end product recovered easily in essentially pure form. A nonexclusive, irrevocable, royalty-free license in the invention herein described, throughout the world for all purposes of the United States Government, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.

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Peoria, IL, United States of America

Edward I Stout