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US4997904A
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Aromatic polyanhydride compositions
Assignee: Massachusetts Institute of Technology
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Filing: 1989-08-25
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Granted: 1991-03-05
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Expires: 2009-08-25
Abstract
Abstract Aromatic anhydride copolymers containing at least two aromatic diacid units, which are soluble in chloroform or dichloromethane to concentrations between approximately 0.5 to 50% weight/volume, melt at temperatures below 180° C., and have low crystallinity are disclosed. The copolymers may contain between 0 and approximately 30% aliphatic diacid units. All copolymers are insoluble in carbon tetrachloride, i.e., less than 0.1% polymer by weight/volume solvent). The desired properties are the result of adding between 10 and 90% of a second aromatic diacid, to the copolymer composition which introduces irregularity in the polymer chains that dramatically alter the polymer properties, decreasing the crystallinity and melting point and increasing the solubility in the common solvents, dichloromethane or chloroform. An additional decrease in Tg and MP, with an increase in flexibility, is obtained by adding small amount of aliphatic diacid, up to about 30%.
Inventors
- 👤 Abraham J. Domb
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 22:44
CPC Classifications
A; A61; A61K; A61K9/00; A61K9/70; A61K9/7007; A61K9/20; A61K9/2004; A61K9/2022; A61K9/2031; C; C08; C08G; C08G67/00; C08G67/04; C08L; C08L73/00; C08L73/02
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
40 words
Anhydride copolymers comprising at least two different aromatic diacid units in a molar ratio of between approximately 10:90 and 90:10, whereby said copolymers are soluble in chloroform and dichloromethane, melt at a temperature below 200° C., and possess low crystallinity.
Claim 2
Dependent Claim
40 words
Anhydride copolymers comprising at least two different aromatic diacid units in a molar ratio of between approximately 10:90 and 90:10, whereby said copolymers are soluble in chloroform and dichloromethane, melt at a temperature below 200° C., and possess low crystallinity.
Claim 3
Dependent Claim
25 words
The anhydride copolymers of claim 1 wherein at least 70% of the diacid units are aromatic diacid units and the remainder are aliphatic diacid units.
Claim 4
Dependent Claim
12 words
The anhydride copolymers of claim 1 having less than about 5% crystallinity.
Claim 5
Dependent Claim
24 words
The anhydride copolymers of claim 1 polymerized from diacids selected from the group consisting of ##STR2## wherein R is a divalent organic radical group
Claim 6
Dependent Claim
26 words
The anhydride copolymers of claim 4 polymerized from diacids selected from the group consisting of isophthalic acid, terephthalic acid, bis(carboxyphenoxyalkanes), bis(carboxyphenylalkanes), and their ring substitution derivatives.
Claim 7
Independent Claim
44 words
A method for making anhydride copolymers comprising: polymerizing at least two different aromatic diacid units in a molar ratio of between approximately 10:90 and 90:10 to form copolymers soluble in chloroform and dichloromethane, melting at a temperature below 200° C., and possessing low crystallinity.
Claim 8
Independent Claim
44 words
A method for making anhydride copolymers comprising: polymerizing at least two different aromatic diacid units in a molar ratio of between approximately 10:90 and 90:10 to form copolymers soluble in chloroform and dichloromethane, melting at a temperature below 200° C., and possessing low crystallinity.
Claim 9
Dependent Claim
28 words
The method for making anhydride copolymers of claim 6 wherein at least 70% of the diacid units are aromatic diacid units and the remainder are aliphatic diacid units.
Claim 10
Dependent Claim
24 words
The method for making anhydride copolymers of claim 6 comprising reacting diacids of the formula: ##STR3## wherein R is a divalent organic radical group.
Claim 11
Dependent Claim
31 words
The method for making anhydride copolymers of claim 8 wherein the aromatic diacids are selected from the group consisting of isophthalic acid, terephthalic acid, bis(carboxyphenoxyalkanes), bis(carboxyphenylalkanes) and their ring substitution derivatives.
Claim 12
Dependent Claim
46 words
The method for making anhydride copolymers of claim 6 wherein said polymerization reaction is effected by first reacting said diacids with acetic anhydride to form dicarboxylic acid diacetyl anhydride prepolymers and then polymerizing the prepolymers in the presence of a coordinative catalyst to form the copolymers.
Claim 13
Dependent Claim
39 words
The method of claim 6 further comprising preparing drug delivery implants by dissolving the copolymer in an organic solvent selected from the group consisting of chloroform and dichloromethane, casting the polymer solution, and removing the solvent from the polymer.
Claim 14
Dependent Claim
23 words
The method of claim 6 further comprising preparing drug delivery implants by melting the copolymer at a temperature of less than 200° C.
Claim 15
Dependent Claim
44 words
A polymer solution comprising between approximately 0.5 and 50% weight/volume of an anhydride copolymer of at least two different aromatic diacids in a molar ratio of between approximately 10 and 90 in an organic solvent selected from the group consisting of chloroform and dichloromethane.
Claim 16
Dependent Claim
44 words
A polymer solution comprising between approximately 0.5 and 50% weight/volume of an anhydride copolymer of at least two different aromatic diacids in a molar ratio of between approximately 10 and 90 in an organic solvent selected from the group consisting of chloroform and dichloromethane.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-03-04 | 1994-09-03 | 1995-03-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-03-04 | 1998-09-03 | 1999-03-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-03-04 | 2002-09-03 | 2003-03-05 | $7700.00 | Window Closed / Lapsed |