Synthesis and Optical Characterization of High Refractive Index Polycarbonates With Thioether‐Binaphthyl Architectures

ABSTRACT Highly refractive index polymers (HRIPs) have emerged as essential materials in the field of optics. According to the Lorentz–Lorenz equation, the refractive index of polymers is influenced by the molecular structure of their constituent chain segments. In this study, a series of poly(binaphthyl thioether carbonate)s (PBNSC S ) were synthesized through melt transesterification of diphenyl carbonate (DPC) with monomers featuring high‐molar‐refractivity naphthalene rings and highly polarizable thioether structures. The structural characteristics and property profiles of the resulting PBNSC S were systematically investigated. The results demonstrate that the obtained co‐polycarbonates exhibit outstanding optical performance, with refractive indices ranging from 1.656 to 1.665, thereby surpassing conventional bisphenol‐A polycarbonate (BPA‐PC). Furthermore, these materials display favorable thermal stability and hydrophobicity, evidenced by glass‐transition temperatures ( T g ) between 105.95°C and 124.22°C, maximum thermal decomposition temperatures ( T dmax ) from 393°C to 405.8°C, and water contact angles varying between 98.85° and 111.08°. This work thus presents a promising strategy for the development of advanced co‐polycarbonates, offering new insights and opportunities for the design of high‐performance optical materials.