Amideimide sizing for carbon fiber

Abstract

Sizing for carbon fibers with uncapped or capped linear polyamideimides. The uncapped linear polyamideimides useful as carbon fiber sizings generally contain repeating units having the general formula: ##STR1## Wherein R.sub.2 =a trivalent organic radical and generally benzenetriyl; R.sub.3 =a divalent organic radical; and n=an integer sufficiently large to provide a strong, tough coating. Useful capped, linear polyamideimide oligomers may be formed by including end caps with an unsaturated functionality (Y) containing a residue selected from the group consisting of: ##STR2## wherein R.sub.1 =lower alkoxy, aryl, aryloxy, substituted alkyl, substituted aryl, halogen, or mixtures thereof; j=0, 1, or 2; i=1 or 2; G=--CH.sub.2 --, --O--, --S--, --SO.sub.2 --, --SO--, --CO--, --CHR--, or --CR.sub.2 --; T=methallyl or allyl; Me=methyl; and R=hydrogen, lower alkyl, or phenyl. Prepregs and composites having carbon fibers sized with such polyamideimides are also described.

Dependencies are inferred from the claim text.