TBAF-Catalyzed Inverse Vulcanization under Mild Conditions Enabling Synthesis of Refractive Indexing, Ultraviolet Blocking and Light Transmiting Sulfur-Rich Polymers

Abstract

The synthesis of inverse vulcanized (IV) organic polysulfides under mild conditions offers an effective strategy to reduce energy costs and enhance safety. In this study, we present a tetrabutylammonium fluoride (TBAF)-catalyzed IV process that enables reactions at ambient temperatures. This protocol significantly expands the methodologies available for IV reactions and broadens the potential applications of the resulting polymers. By incorporating 5 wt% TBAF as a catalyst, this method allows the use of both activated and non-activated olefins in IV processes under mild conditions. The method is characterized by low energy consumption, a simple catalyst system, and the elimination of H₂S by-products. The synthesized terpolymer of S₈, ethylene glycol dimethacrylate (EGDMA), and N,N'-methylene diacrylamide (MBA) exhibits excellent optical transparency, a high refractive index (nav > 1.54), and exceptional ultraviolet (UV) blocking properties across the entire UV range (200–400 nm), while maintaining high transmission in the visible light spectrum. The reaction mechanism was further explored through experimental studies and density functional theory (DFT) calculations.