Effects of thioether content on thermal and optical properties of polyamides

4,4′‐Bis(4‐chloroformylphenylthio)benzene was synthesized in two steps and was reacted with diamine‐containing thioether and amide units to prepare a polyamide containing high contents of thioether groups. The intrinsic viscosities of the polyamides were 0.76–0.87 dL g −1 . These polyamides had excellent thermal properties, with glass transition temperatures of 234.8–269 °C and initial degradation temperatures of 461–469.7 °C. They showed improved solubility in polar aprotic solvents and could form moderate strength films with a tensile strength of 75.2–111.6 MPa and storage modulus of 1.0–1.3 GPa (at 220 °C). These polymer films also had good optical properties, including an optical transmittance of the aromatic polyamide film at 450 nm that was higher than 90%. Additionally, the high quantity of thioether units provided the polymers with high refractive indices of 1.700–1.704 and low birefringences of 0.007–0.008. Copyright © 2012 Society of Chemical Industry