Synthesis of sulfur-containing poly(thioester)s with high refractive indices and high Abbe numbers

Abstract

New poly(thioester)s (PTE)s containing sulfide and alicyclic units in polymer chains with high refractive indices and high Abbe numbers have been developed as thermoplastics. The PTEs were synthesized by the polycondensation reaction of 2,5-bis(sulfanylmethyl)-1,4-dithiane (BMMD) with 1,3-adamantanedicarbonyl dichloride (ADC) or cyclohexanedicarbonyl dichloride (CDC). Tough, flexible, and transparent amorphous polymer films were obtained. All polymers showed good thermal stability such as 5% weight-loss temperatures in the range 301–307 °C under nitrogen, and glass transition temperatures (T_g) in the range 65–110 °C. Poly(BMMD/ADC) and poly(BMMD/CDC) showed high refractive indices of 1.6149 and 1.6217, Abbe numbers of 32.1 and 30.0, respectively, and high transparency in the visible region.