US3976552A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Water-soluble graft polymers produced by an outwardly dry radiation polymerization process
Assignee: United States Department of Agriculture
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Filing: 1975-08-13
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Granted: 1976-08-24
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Expires: 1995-08-13
Abstract
Abstract A method was discovered of graft polymerizing water-soluble monomers with starch under conditions which are outwardly dry appearing. Conversion of monomer to polymer is nearly quantitative; and, since excess water is not present, there is no need for separate isolation and drying steps.
Inventors
- 👤 George F. Fanta
- 👤 Robert C. Burr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 10:12
CPC Classifications
C; C08; C08F; C08F251/00; C08L; C08L1/00; Y; Y10; Y10S; Y10S522/00; Y10S522/911
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
142 words
A method of preparing starch graft copolymers comprising the steps of: a. preparing a concentrated aqueous solution containing from about 20 to 50 percent of a water-soluble monomer selected from the group consisting of acrylamide, N,N,N-trimethylaminoethyl methacrylate methyl sulfate, methacrylamide, acrylic acid, 2-hydroxy-3-methacryloyloxypropyltrimethylammonium chloride, or mixtures of the same; adding starch to the solution resulting from step (a) in sufficient quantities to absorb all of said solution and to give a reaction mass having an outwardly dry or slightly damp appearance, said starch being present in an amount such that the ratio of starch to monomer on a dry weight basis is from 1:1 to 20:1; c. purging the starch-monomer mixture resulting from step (b) with an inert gas; and d. irradiating the purged mixture resulting from step (c) with gamma rays from cobalt-60 to a total dose of about 0.1 Mrad.
Claim 2
Independent Claim
142 words
A method of preparing starch graft copolymers comprising the steps of: a. preparing a concentrated aqueous solution containing from about 20 to 50 percent of a water-soluble monomer selected from the group consisting of acrylamide, N,N,N-trimethylaminoethyl methacrylate methyl sulfate, methacrylamide, acrylic acid, 2-hydroxy-3-methacryloyloxypropyltrimethylammonium chloride, or mixtures of the same; adding starch to the solution resulting from step (a) in sufficient quantities to absorb all of said solution and to give a reaction mass having an outwardly dry or slightly damp appearance, said starch being present in an amount such that the ratio of starch to monomer on a dry weight basis is from 1:1 to 20:1; c. purging the starch-monomer mixture resulting from step (b) with an inert gas; and d. irradiating the purged mixture resulting from step (c) with gamma rays from cobalt-60 to a total dose of about 0.1 Mrad.
Claim 3
Dependent Claim
22 words
A method as described in claim 1 wherein the reaction mass of step (b) contains from about 24 to 73 percent water.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-08-24 | 1980-02-23 | 1980-08-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-24 | 1984-02-23 | 1984-08-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-24 | 1988-02-23 | 1988-08-24 | $7700.00 | Window Closed / Lapsed |