Preparation of Degradable and Sequence-Controlled Aliphatic Polysulfones by Group Transfer Radical Polymerization

The incorporation of sulfur atoms into polymer backbones for the synthesis of sulfur-containing polymers, such as aliphatic polysulfones, not only enhances degradability but also imparts many distinctive properties to these materials. Traditional synthetic methods encounter substantial challenges in achieving sequence-controlled aliphatic polysulfones with high molecular weights (MW), which significantly limits their applications. We report a novel approach for synthesizing aliphatic polysulfones using the strategy of sulfonyl radical-mediated group transfer radical polymerization (GTRP). This protocol employs a practical SO₂-free pathway and produces a series of ABC sequence-defined high-MW polymers (up to 199.2 kg/mol). The resultant aliphatic polysulfone exhibits remarkable full-degradability at ambient temperature under strong basic conditions, and offers optical properties - including refractive index and Abbe number - comparable to those of commercially utilized polycarbonate. Additionally, density functional theory (DFT) calculations have been performed to corroborate the non-desulfonylative Smiles rearrangement mechanism implicated in the GTRP process.