(673d) Isosorbide and Glucarodilactone-Based Polyethers and Poly(ester-thioethers) Via Ring-Opening and Photointiated Thiol-Ene Polymerization

With the aim of preparing sustainable and degradable polymers from sugar-derived precursors, a family of poly(ester-thioethers) were synthesized by photoinitiated thiol–ene polymerization of monomers incorporating D-glucaro-1,4:6,3-dilactone (GDL). In addition, a ring-opening polymerization method of a trianhydrohexitol derived from isosorbide (1,4:2,5:3,6-trianhydro-D-mannitol) was also discovered. High-throughput screening was employed to quickly evaluate ROP catalysts and conditions. Density functional theory calculations provided insights into the interplay of ring-strain enthalpy and free energy of activation for ring opening. The resultant macromolecular architecture (i.e. generation of linear vs. cyclic polymers) can be tuned by careful selection of the polymerization conditions. The effects of structure on the observed mechanical performance and degradability were also examined. GDL units in the polymers enabled rapid degradation under basic aqueous conditions yet were stable in acidic and neutral conditions. Isosorbide derivatives were generally stable from degradation. Tensile testing of these materials showed robust mechanical properties, including tunable moduli, strength, and ductility.