Wholly aromatic polyamide foam
AssigneeE. I. Du Pont de Nemours and Company
InventorWesley Memeger, Jr.
Life of this patent
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Abstract
Aromatic polyamide foams having a density of 0.025 to 0.7 g./cm..sup.3 are prepared by heating N-alkyl aromatic polyamides having at least one .beta. hydrogen atom on the alkyl groups, a plasticizer and an aromatic sulfonic acid catalyst at 250.degree. to 340.degree. C. for a length of time sufficient to remove substantially all of the N-alkyl groups.
Claims4
A wholly aromatic polyamide foam prepared by dealkylation of an N-alkyl wholly aromatic polyamide wherein either the diamine residue or the dicarboxylic acid residue is para oriented, said foam having a density of 0.025 to 0.7 g./cm..sup.3 wherein the cell walls are oriented as evidenced by a birefringence of at least 10% of the maximum possible birefringence and having substantially no residual N-alkyl groups.
Dependencies are inferred from the claim text.