Highly Refractive Polyimides Derived from Efficient Catalyst-Free Thiol-Yne Click Polymerization

Polyimides (PIs), owing to their inherent high refractive index and excellent physical properties, are required in advanced optical applications. They are traditionally synthesized through conventional two-step polycondensation, followed by high-temperature or chemical imidization, inevitably increasing energy consumption, environmental pollution, and production duration. Herein, for the first time, we synthesized PIs consisting of vinylene sulfide linkages via an efficient catalyst-free thiol-yne click polymerization, which would be accomplished within 2 h at 25 degrees C by simply mixing the dithiols and bisimide-containing diynes in THF, affording PIs with tensile strength ranging from 106.3 to 114.9 MPa, glass transition temperature up to 238 degrees C, thermal decomposition temperature as high as 381 degrees C, and desirable solubility, so that it was easily cast from solution into tough films. Moreover, the BPADA-TBT PI film demonstrates good optical performance, with its refractive index exceeding 1.70 at 633 nm and transmittance above 81% at 450 nm, making it a potential candidate in advanced optical applications.

Automated summary

In this study, polyimides with vinylene sulfide linkages were synthesized efficiently through a catalyst-free thiol-yne click polymerization method. These PIs exhibited high tensile strength, glass transition temperature, thermal decomposition temperature, and good solubility, making them promising candidates for advanced optical applications.