Conjugation-Disruption Strategy Enables Colorless, Chemically Recyclable, and High-Refractive-Index Optical Plastics Cross-Linked by Dynamic Thiourethanes

Developing high-refractive-index polymers (HRIPs) that simultaneously exhibit high optical transparency, mechanical robustness, and excellent sustainability remains a formidable challenge. Herein, we report a conjugation-disruption strategy to fabricate colorless and chemically recyclable HRIPs with high mechanical robustness and efficient chemical recyclability, denoted as PTU-4. Synthesized via the copolymerization of 4,4′-thiobisbenzenethiol (TB), hexamethylene diisocyanate, and phenol-functionalized triazine, PTU-4 integrates high atomic polarizability with a strategically disrupted π-conjugation network, exhibiting a refractive index of 1.73 and optical transparency comparable to commercial optical plastics. Beyond optical performance, PTU-4 exhibits a high tensile strength of ∼74.2 MPa, Young’s modulus of ∼2.45 GPa, remarkable wear resistance, and outstanding solvent resistance. Notably, thiourethane exchange imparts PTU-4 with intrinsic healing and reprocessing capabilities, while ammonolysis of thiourethanes enables efficient chemical recycling of PTU-4 to simultaneously recover high-value TB monomers and generate high-performance elastomers. This work establishes a generalizable conjugation-disruption strategy for developing colorless HRIPs with excellent sustainability and outstanding mechanical performance.