US4448657A
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Methods employing magnetic fields for controlling emulsion polymerization
Assignee: TURRO NICHOLA J
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Filing: 1981-10-23
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Granted: 1984-05-15
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Expires: 2001-10-23
Abstract
Abstract Emulsion polymerization with initiators that produce triplet radical pairs is controlled by the application of a magnetic field. Both the rate of polymerization and the molecular weight of the polymer can be controlled. Emulsion polymerization with oil-soluble initiators is enabled to proceed to high conversions at convenient rates and to produce polymers having molecular weights comparable to or higher than those achievable with conventional water-soluble initiators.
Inventors
- 👤 Nicholas J. Turro
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 18:20
CPC Classifications
C; C08; C08F; C08F2/00; C08F2/46; C08F2/48; C08F2/12; C08F2/16; C08F2/22; Y; Y10; Y10S; Y10S522/00; Y10S522/91
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
75 words
A method of controlling an emulsion polymerization reaction comprising employing as an initiator for the reaction an oil-soluble photoinitiator which produces triplet radical pairs, irradiating the photoinitiator to produce such triplet radical pairs, providing for the photoinitiator a plurality of loci of polymerization initiation having the restricted dimensionality of microscopic reaction vessels, and applying a magnetic field having a strength of at least about 100 Gauss and sufficient to afford significant enhancement of polymerization initiation.
Claim 2
Independent Claim
75 words
A method of controlling an emulsion polymerization reaction comprising employing as an initiator for the reaction an oil-soluble photoinitiator which produces triplet radical pairs, irradiating the photoinitiator to produce such triplet radical pairs, providing for the photoinitiator a plurality of loci of polymerization initiation having the restricted dimensionality of microscopic reaction vessels, and applying a magnetic field having a strength of at least about 100 Gauss and sufficient to afford significant enhancement of polymerization initiation.
Claim 3
Dependent Claim
17 words
The method of claim 1, wherein said microscopic reaction vessels are provided by a micelle-forming surfactant solution.
Claim 4
Dependent Claim
22 words
The method of claim 1, wherein the photoinitiator is selected from the group consisting of benzyl ketone, benzoin, 1,1'-azoethane, and 4,4'-di-t-butyldibenzyl ketone.
Claim 5
Dependent Claim
17 words
The method of claim 3, wherein the emulsion polymerization is one of styrene, methylmethacrylate, and acrylic acid.
Claim 6
Dependent Claim
30 words
The method of claim 1, comprising adjusting the strength of the magnetic field to control the molecular weight and the rate of formation of a polymer produced by said reaction.
Claim 7
Dependent Claim
18 words
The method of claim 1, wherein said applying comprises applying a magnetic field of 5,000 Gauss or less.
Claim 8
Dependent Claim
16 words
The method of claim 6, wherein the magnetic field is in the range of 100-1,000 Gauss.
Claim 9
Dependent Claim
17 words
The method of claim 1, wherein the magnetic field is applied with a spatially varying field strength.
Claim 10
Dependent Claim
19 words
The method of claim 1, wherein said irradiating comprises irradiating with light which varies spatially in a predetermined manner.
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) | 1987-05-15 | 1987-11-14 | 1988-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-05-15 | 1991-11-14 | 1992-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-05-15 | 1995-11-14 | 1996-05-15 | $7700.00 | Window Closed / Lapsed |