N-METHYLATED COPOLY(IMIDE AMIDE)S CONTAINING HEXAFLUOROISOPROPYLIDENE

A synthetic method was developed to produce N,N'-dimethylated diamines which were then used to prepare poly(imide amide)s. Thus, N,N'-dimeth yl-4,4'-bis(4-aminophenoxy)biphenyl and '-dimethyl-2,2-bis(4-aminophen yl)hexafluoropropane were condensed at 0 degrees C in dimethylacetamid e with hlorocarboxyphenyl)phthalimidyl]hexafluoropropane. The yields w ere 76-92%, viscosities 0.28-2.26 dl g(-1), water absorptions 0.16-0.3 7 wt% and thermal stabilities around 460 degrees C by thermogravimetri c analysis. The addition of the methyl group caused lower molecular we ights but superior thermal stability (isothermally) and decreased colo ur. Copyright (C) 1996 Elsevier Science Ltd.