A facile approach towards optically isotropic, colorless, and thermoplastic polyimidothioethers with high refractive index

A series of novel optically isotropic, transparent, and thermoplastic polyimidothioethers (PITEs) with high refractive index were prepared via Michael polyaddition from commercially available bismaleimides and dithiols. These polymers were readily soluble in various organic solvents and showed useful thermal stability associated with high glass-transition temperatures. In addition to the useful thermal processing window up to 190 °C, these PITEs also exhibit a high refractive index and ultra-low birefringence of 1.6763 and 0.0002, respectively.