Chain-extending nitrile end-capped polyimides
AssigneeUniversity of Notre Dame du Lac
InventorGaetano Francis D'Alelio
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Abstract
Aromatic polyimides with nitrile end groups are chain-extended (molecular weight increased) by polymerization using Lewis acid salts as catalyst. Molecular weights are increased with little or no by-product formation. These 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 nitrile compounds such as aminobenzyl cyanide and aminobenzonitrile.
Claims10
A polymeric chain-extending process comprising:
- heating at a temperature in the range of about 150.degree.-450.degree. C. a polyimide in the presence of a catalytic amount of a Lewis acid salt catalyst, said polyimide of the formula:
- ##STR21## 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
- n is a positive integer of at least one.
A polymeric chain-extending process comprising:
- heating a polyimide at a temperature in the range of about 150.degree.-450.degree. C. in the presence of about 0.15-5% by weight, based on the weight of the polyimide, of a Lewis acid salt catalyst, said polyimide of 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.sup.IV, wherein R.sup.IV is alkylene of 1 to 3 carbon atoms, ##STR29## R is ##STR30## and n is a positive integer from 1 to 20.
The polymerized product of a polyimide having the formula:
- ##STR31## wherein n is a positive integer of at least 2, said product being prepared by heating said polyimide to a temperature in the range of about 150.degree.-450.degree. C or by heating said polyimide in the presence of a catalytic amount of a Lewis acid salt catalyst to a temperature in the range of about 150.degree.-450.degree. C.
The polymerized product of a polyimide having the formula:
- ##STR32## wherein n is a positive integer of at least 2, said product being prepared by heating said polyimide to a temperature in the range of about 150.degree.-450.degree. C or by heating said polyimide in the presence of a catalytic amount of a Lewis acid salt catalyst to a temperature in the range of about 150.degree.-450.degree. C.
The polymerized product of a polyimide having the formula:
- ##STR33## wherein n is a positive integer of at least 2, said product being prepared by heating said polyimide to a temperature in the range of about 150.degree.-450.degree. C or by heating said polyimide in the presence of a catalytic amount of a Lewis acid salt catalyst to a temperature in the range of about 150.degree.-450.degree. C.
Dependencies are inferred from the claim text.