Biobased Copolymers via Cationic Ring-Opening Copolymerization of Levoglucosan Derivatives and ε-Caprolactone

Simultaneousring-opening copolymerization is a powerful strategyfor the synthesis of highly functional copolymers from different typesof cyclic monomers. Although copolymers are essential to the plasticsindustry, environmental concerns associated with current fossil-fuel-basedsynthetic polymers have led to an increasing interest in the use ofrenewable feedstock for polymer synthesis. Herein, we report a scalablesynthetic platform to afford unique polysaccharides with differentpendant functional groups from biomass-derived levoglucosan and & epsilon;-caprolactonevia cationic ring-opening copolymerization (cROCOP). Biocompatibleand recyclable bismuth triflate was identified as the optimal catalystfor cROCOP of levoglucosan. Copolymers from tribenzyl levoglucosanand & epsilon;-caprolactone, as well as from tribenzyl and triallyl levoglucosan,were successfully synthesized. The tribenzyl levoglucosan monomercomposition ranged from 16% to 64% in the copolymers with & epsilon;-caprolactoneand 22% to 79% in the copolymers with triallyl levoglucosan. The allyliclevoglucosan copolymer can be utilized as a renewably derived scaffoldto modify copolymer properties and create other polymer architecturesvia postpolymerization modification. Monomer reactivity ratios weredetermined to investigate the copolymer microstructure, indicatingthat levoglucosan-based copolymers have a gradient architecture. Additionally,we demonstrated that the copolymer glass transition temperature (T (g), ranging from -44.3 to 33.8 & DEG;C),thermal stability, and crystallization behavior could be tuned basedon the copolymer composition. Overall, this work underscores the utilityof levoglucosan as a bioderived feedstock for the development of functionalsugar-based copolymers with applications ranging from sustainablematerials to biomaterials.

Automated summary

Simultaneousring-opening copolymerization is a powerful strategy for highly functionalcopolymer synthesis. This study introduces a scalable synthetic platformto produce unique polysaccharides with different functional groups frombiomass-derived levoglucosan and ε-caprolactone. Biocompatible and recyclablebismuth triflate was identified as the optimal catalyst for the copolymerization.Copolymers from tribenzyl levoglucosan and ε-caprolactone and from tribenzyland triallyl levoglucosan were successfully synthesized.