Thianthrene-Containing Polymers: Polyimides Aramids, and Polybenzoxazoles

Document Type

Article

Publication Date

1996

Department

Polymers and High Performance Materials

Abstract

Thianthrene and thioether-containing aromatic dicarboxylic acids were readily synthesized by nucleophilic aromatic substitution. Polyamides obtained from the diacids displayed good thermal stabilities and solubilities enhanced over typical aramids. Films displayed good toughness and flexibility, consistent with high molecular weight and low crystallinity.

Thianthrene-2,3,7,8-tetracarboxylic dianhydride was prepared starting from dichlorophthalic acid, making the N-phenylimide and forming the thianthrene ring with either thioamides or sodium sulfide. Polyimides were synthesized by the low temperature formation of poly(amic acid) solutions which were cast into films and then thermally cyclized. Flexible diamines gave creasible films while rigid diamines gave brittle films, with excellent thermal stability. Polymer solubility was not enhanced by incorporating the bent thianthrene structure.

New thianthrene-containing PBOs were synthesized by the polycondensation reaction of thianthrene dicarbonyl chlorides with biso-aminophenols in PPA. The PBOs exhibit high glass transition temperatures and good thermal stabilities. No solubility improvements were observed but films were transparent and tough.

Publication Title

ACS Symposium Series

Volume

624

First Page

403

Last Page

420

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