US4026833A
Expired / Lapsed
US
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Chain-extending polyimides with aromatic polyisocyanates
Assignee: University of Notre Dame
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Filing: 1975-03-14
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Granted: 1977-05-31
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Expires: 1995-03-14
Abstract
Abstract Aromatic polyimides with anhydride end groups are chain-extended (molecular weight increased) by reacting them with aromatic polyisocyanates such as tolylene-2,4-diisocyanate. These polyimides can be shaped and formed prior to chain-extending. Thermally stable, polyimide foams are formed by the reaction.
Inventors
- 👤 Gaetano Francis D'Alelio
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 06:15
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1057; C08G73/1064; C08G18/00; C08G18/06; C08G18/28; C08G18/40; C08G18/64; C08G18/6415; C08G18/6438; C08G73/1003; C08G73/1067; C08G73/1071; Y; Y10; Y10S; Y10S525/00; Y10S525/925; Y10S525/928
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
103 words
A polymeric chain-extending process comprising: reacting at a temperature of about 150°-450° C. a polyimide of the formula: ##STR22## 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, n is a positive integer of at least 1, with at least one mole, per mole of polyimide, of an aromatic polyisocyanate of the formula Ar(NCO) m wherein Ar is an aromatic organic radical and m is a positive integer of 2-5.
Claim 2
Dependent Claim
103 words
A polymeric chain-extending process comprising: reacting at a temperature of about 150°-450° C. a polyimide of the formula: ##STR22## 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, n is a positive integer of at least 1, with at least one mole, per mole of polyimide, of an aromatic polyisocyanate of the formula Ar(NCO) m wherein Ar is an aromatic organic radical and m is a positive integer of 2-5.
Claim 3
Dependent Claim
11 words
The process of claim 1 wherein n is at least 4.
Claim 4
Dependent Claim
30 words
The process of claim 1 wherein the isocyanate is a diisocyanate selected from the group consisting of tolylene diisocyanate, xylylene diisocyanate, benzylene diisocyanate, phenylene diisocyanate, naphthylene diisocyanate and diphenylene diisocyanate.
Claim 5
Dependent Claim
25 words
The process of claim 1 wherein at least one mole of polyisocyanate is used per mole of polyimide an n is from 1 to 20.
Claim 6
Dependent Claim
53 words
The process of claim 1 wherein Ar' is selected from the group consisting of ##STR23## and Ar is selected from the group consisting of ##STR24## and multiples thereof connected to each other by R IV , wherein R IV is alkylene of 1 to 3 carbon atoms, ##STR25## --O--,--S--,--CH=CH--, and --SO 2 --.
Claim 7
Dependent Claim
120 words
A polymeric chain-extending process comprising: heating a polyimide at a temperature in the range of about 150° to 400° C. with about 1-5 moles of an aromatic diisocyanate per mole of polyimide, said diisocyanate selected from the group consisting of tolylene diisocyanate, xylylene diisocyanate, benzylene diisocyanate, phenylene diisocyanate, naphthylene diisocyanate and diphenylene diisocyanate and said polyimide having the formula: ##STR26## wherein Ar' is selected from the group consisting of ##STR27## and Ar is selected from the group consisting of ##STR28## and multiples thereof connected to each other by R IV , wherein R IV is alkylene of 1 to 3 carbon atoms, ##STR29## --O--, --S--, --CH=CH--, and --SO 2 -- and n is a positive integer of 4 to 20.
Claim 8
Dependent Claim
120 words
A polymeric chain-extending process comprising: heating a polyimide at a temperature in the range of about 150° to 400° C. with about 1-5 moles of an aromatic diisocyanate per mole of polyimide, said diisocyanate selected from the group consisting of tolylene diisocyanate, xylylene diisocyanate, benzylene diisocyanate, phenylene diisocyanate, naphthylene diisocyanate and diphenylene diisocyanate and said polyimide having the formula: ##STR26## wherein Ar' is selected from the group consisting of ##STR27## and Ar is selected from the group consisting of ##STR28## and multiples thereof connected to each other by R IV , wherein R IV is alkylene of 1 to 3 carbon atoms, ##STR29## --O--, --S--, --CH=CH--, and --SO 2 -- and n is a positive integer of 4 to 20.
Claim 9
Dependent Claim
19 words
A cross-linked polymeric foam prepared by the process of claim 1 wherein m is a positive integer at 3-5.
Claim 10
Dependent Claim
19 words
A cross-linked polymeric foam prepared by the process of claim 2 wherein m is a positive integer of 3-5.
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) | 1980-05-30 | 1980-11-29 | 1981-05-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-30 | 1984-11-29 | 1985-05-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-30 | 1988-11-29 | 1989-05-31 | $7700.00 | Window Closed / Lapsed |