Thianthrene-containing polyamides

Thianthrene-containing polyamides have also been prepared by reacting thianthrene-2,7-dicarboxylic acid chloride with aromatic and aliphatic diamines at low-temperature. The polymerization of thianthrene-2,7-dicarboxylic acid chloride and 1,4-phenylenediamine yielded 81% polyamide with an inherent viscosity of 0.75 dL/g, although no other polymers or characterization results were discussed. 

Thianthrene-containing polyamides were also prepared by converting thianthrene-containing polyketones to polyamides by Schmidt and Beckmaim rearrangements. These polymers derived had lower inherent viscosities relative to those prepared by the low-temperature reaction of diamines and diacid chlorides. 

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

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