US4400496A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Water-soluble graft copolymers of starch-acrylamide and uses therefor
Assignee: University of Florida
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Filing: 1980-09-22
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Granted: 1983-08-23
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Expires: 2000-09-22
Abstract
Abstract Graft copolymers having starch as the central chain with grafted side chains of acrylamide or acrylamide-acrylic acid, and a process for preparation of such copolymers in the presence of Ce+4 or other redox initiators. These copolymers are employed in preparing highly viscous aqueous solutions that are particularly useful in oil recovery from subterranean wells.
Inventors
- 👤 George B. Butler
- 👤 Thieo E. Hogen-Esch
- 👤 John J. Meister
- 👤 Huey Pledger, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:59
CPC Classifications
C; C08; C08F; C08F251/00
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
31 words
Water-soluble graft copolymer comprising a backbone molecule of water-soluble starch with branch chains grafted thereto of polymerized acrylamide units or a mixture of polymerized acrylamide units and polymerized acrylic acid units.
Claim 2
Dependent Claim
31 words
Water-soluble graft copolymer comprising a backbone molecule of water-soluble starch with branch chains grafted thereto of polymerized acrylamide units or a mixture of polymerized acrylamide units and polymerized acrylic acid units.
Claim 3
Dependent Claim
15 words
The graft copolymer of claim 1 wherein all of said branch chains are polymerized acrylamide.
Claim 4
Dependent Claim
37 words
The graft copolymer of claim 1 which has the property of increasing the viscosity of water from 2 to 1000 times that of pure water when dissolved in water at concentrations of 0.001 to 2.0 weight percent.
Claim 5
Dependent Claim
14 words
The graft copolymer of claim 1 having a molecular weight of 300,000 to 20,000,000.
Claim 6
Dependent Claim
26 words
The graft copolymer of claim 3 in which the molecular weight is 1,000,000 to 5,000,000 and each starch molecule has 1-18 of said grafted branch chains.
References Cited (Backward Citations)
US3095391A
Cited
US3332897A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-08-22 | 1987-02-21 | 1987-08-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-22 | 1991-02-21 | 1991-08-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-22 | 1995-02-21 | 1995-08-23 | $7700.00 | Window Closed / Lapsed |