Thianthrene-Containing Polymers: Polyimides Aramids, and Polybenzoxazoles
Polymers and High Performance Materials
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.
ACS Symposium Series
Johnson, R. A.,
Mathias, L. J.
(1996). Thianthrene-Containing Polymers: Polyimides Aramids, and Polybenzoxazoles. ACS Symposium Series, 624, 403-420.
Available at: https://aquila.usm.edu/fac_pubs/5470