US4055543A
Expired / Lapsed
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Chain-extending Schiff base terminated polyimides and method of preparation
Assignee: Individual
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Filing: 1975-05-27
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Granted: 1977-10-25
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Expires: 1995-05-27
Abstract
Abstract Aromatic polyimides with Schiff base end groups are chain-extended (molecular weight increase) by heating the polyimides, preferably in the presence of Lewis acid salts as catalyst. Molecular weights are increased with little or no by-product formation. The polyimides can be shaped and formed prior to the polymerization. The aromatic polyimides appropriate for chain-extending are formed by the reaction of aromatic dianhydrides, aromatic diamines and a Schiff base monoamine such as p-amino-benzylidene-aniline, p-amino-benzylidene-4-vinylaniline and p-aminobenzylidine-4-ethynylaniline.
Inventors
- 👤 Gaetano Francis D'Alelio
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:54
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1067; C08G73/1071; C08G73/1003; C08G73/1007; C08G73/101; C08G73/1057; C08G73/106; C08G73/1064
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
96 words
A polymeric chain-extending process comprising: heating a polyimide, at a temperature in the range of about 150°-450° C, of the formula: ##STR9##wherein Ar' is a tetravalent aromatic organic radical, the four carbonyl groups being attached directly to separate carbon atoms and each pair of carbonyl groups being attached to adjacent carbon atoms in the Ar' radical, Ar is a divalent aromatic organic radical, R is a hydrocarbon radical of 1 to 12 carbon atoms, and R" is a hydrocarbon radical of 1 to 12 carbon atoms, and n is a positive integer of at least one.
Claim 2
Dependent Claim
96 words
A polymeric chain-extending process comprising: heating a polyimide, at a temperature in the range of about 150°-450° C, of the formula: ##STR9##wherein Ar' is a tetravalent aromatic organic radical, the four carbonyl groups being attached directly to separate carbon atoms and each pair of carbonyl groups being attached to adjacent carbon atoms in the Ar' radical, Ar is a divalent aromatic organic radical, R is a hydrocarbon radical of 1 to 12 carbon atoms, and R" is a hydrocarbon radical of 1 to 12 carbon atoms, and n is a positive integer of at least one.
Claim 3
Dependent Claim
17 words
The process of claim 1 wherein R is an aromatic radical and n is at least 4.
Claim 4
Dependent Claim
9 words
The process of claim 1 wherein R" is ##STR10##
Claim 5
Dependent Claim
50 words
The process of claim 1 wherein Ar' is selected from the group consisting of Ar is selected from the group consisting of ##STR11##multiples thereof connected to each other by R IV , wherein R IV is alkylene of 1 to 3 carbon atoms, ##STR12##--O--, --S--, --CH═CH--, and --SO 2 --.
Claim 6
Dependent Claim
18 words
The process of claim 1 wherein heating is at a temperature in the range of about 200°-300° C.
Claim 7
Dependent Claim
25 words
The process of claim 1 wherein the heating is conducted in the presence of about 0.15 -3% by weight of a Lewis acid salt catalyst.
Claim 8
Dependent Claim
47 words
The process of claim 6 wherein the Lewis acid salt catalyst is at a concentration of about 0.15-3% by weight of the polyimide, and the salt is selected from the group consisting of AlCl 3 , SbCl 5 , ZnCl 2 , ZnSO 4 and copper salts.
Claim 9
Dependent Claim
95 words
A polymeric chain-extending process comprising: heating a polyimide at a temperature in the range of about 150°-450° C. in the presence of about 0.15-3% by weight, based on the weight of the polyimide, of a Lewis acid salt catalyst, said polyimide of the formula: ##STR13##wherein Ar' is a tetravalent aromatic organic radical, the four carbonyl groups being attached directly to separate carbon atoms and each pair of carbonyl groups being attached to adjacent carbon atoms in the Ar' radical, Ar is a divalent aromatic organic radical, ##STR14##n is a positive integer from 1 to 20.
Claim 10
Dependent Claim
95 words
A polymeric chain-extending process comprising: heating a polyimide at a temperature in the range of about 150°-450° C. in the presence of about 0.15-3% by weight, based on the weight of the polyimide, of a Lewis acid salt catalyst, said polyimide of the formula: ##STR13##wherein Ar' is a tetravalent aromatic organic radical, the four carbonyl groups being attached directly to separate carbon atoms and each pair of carbonyl groups being attached to adjacent carbon atoms in the Ar' radical, Ar is a divalent aromatic organic radical, ##STR14##n is a positive integer from 1 to 20.
Claim 11
Dependent Claim
50 words
The process of claim 8 wherein Ar' is selected from the group consisting of ##STR15##Ar is selected from the group consisting of ##STR16##multiples thereof connected to each other by R IV , wherein R IV is alkylene of 1 to 3 carbon atoms, ##STR17##--O--, --S--, --CH═CH--, and --SO 2 --.
Claim 12
Dependent Claim
35 words
The process of claim 8 wherein the Lewis acid salt catalyst is selected from the group consisting of AlCl 3 , SbCl 3 , SbCl 5 , ZnCl 2 , ZnSO 4 and copper salts.
Claim 13
Dependent Claim
10 words
A cross-linked polymer prepared by the process of claim 1.
Claim 14
Dependent Claim
10 words
A cross-linked polymer prepared by the process of claim 5.
Claim 15
Dependent Claim
10 words
A cross-linked polymer prepared by the process of claim 8.
Claim 16
Dependent Claim
10 words
A cross-linked polymer prepared by the process of claim 10.
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) | 1980-10-24 | 1981-04-25 | 1981-10-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-10-24 | 1985-04-25 | 1985-10-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-10-24 | 1989-04-25 | 1989-10-25 | $7700.00 | Window Closed / Lapsed |