Poly(Glycerol-Sulfur) as a Functional Sustainable Nanomaterial: Synthesized by Anionic Ring Opening Polymerization of...

Elemental sulfur is an abundant by-product of the petroleum industry, yet its controlled incorporation into functional polymer architectures remains challenging. Here, we report a one-pot, moderate-temperature (120°C) anionic copolymerization of elemental sulfur (S₈) with glycidol to produce hyperbranched poly(glycerol-sulfur)s with tunable molecular weights (5-30 kDa) and sulfur contents (3-11 wt%) on the gram scale. The reaction proceeds under markedly milder conditions than conventional sulfur polymerizations, enabling precise control over polymer structure and programmable, redox-triggered backbone cleavage rates in glutathione-rich environments. Comprehensive spectroscopic characterization and control experiments provided mechanistic insights into the copolymerization of S₈ and glycidol. The method is readily scalable to tens of grams and affords structural precision unattainable by high-temperature radical routes. As a proof of concept, the copolymers were functionalized with the cytotoxic DM1 via thiol-disulfide exchange, yielding nanocarriers that release over 90% of the payload within 12 h under reductive conditions and significantly reduced the viability of MCF7 breast cancer cells.