Polyanhydrides, 5. Thermotropic poly(ester anhydrides) derived from monoalkylthioterephthalic acids, hydroquinone and 4-hydroxybenzoic acid

✍ Scribed by Hans R. Kricheldorf; Angelika Domschke

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 507 KB
• Volume: 195
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.1994.021950311

✦ Synopsis

Abstract

Monoalkylthioterephthalic acids and their acyl chlorides were prepared via nucleophilic substitution of diethylbromo‐ or diethyl chloroterephthalate with thiols. Various poly(ester anhydrides) were synthesized by polycondensation of alkylthioterephthaloyl chloride with silylated 4‐hydroxybenzoic acid and silylated hydroquinone. The resulting poly(ester anhydrides) were characterized by elemental analyses, inherent viscosities, IR spectroscopy, differential scanning calorimetry (DSC) and wide‐angle X‐ray scattering (WAXS) measurements, optical microscopy and ^13^C NMR cross polarization/magic angle spinning (CP/MAS) spectroscopy. For the chain packing of these monosubstituted poly(ester anhydrides) a sanidic type of layer structure with a “back‐to‐back array” of the main chains is proposed. The alkyl side chains form ordered domains with predominantly all‐trans conformations. In most cases, three endotherms are observable in the DSC heating traces corresponding to the melting of the side chains and to reversible transitions into two different liquid‐crystalline phases.