A straightforward access to functionalizable polymers through ring-opening metathesis polymerization of levoglucosenone-derived monomers

Abstract

Levoglucosenone (LGO) is a cellulose-derived and commercially available platform molecule that is produced at an industrial scale. LGO contains a highly reactive double bond that was used to produce two isomers of norbornene-containing LGO monomers, endo-N-LGO (1) and exo-N-LGO (2). Furthermore, Baeyer-Villiger oxidation of 1 was performed to yield a highly-valuable chiral monomer, endo-N-HBO (3). The norbornene moiety of the prepared monomers was readily polymerized by ring-opening metathesis polymerization (ROMP) in the presence of GI catalyst to access highly thermostable polymers with Td5% up to 360 °C in the case of N-LGO-based polymers and Td5% in the range of 374–380 °C when 3 was polymerized, such range of Td5% being the highest reported up-to-date for the LGO-derived polymers. The effect of monomer concentration over the polymerization process was studied and showed that 4 M solutions lead to a better monomer conversion while preserving the control over the polymer structure and reducing the environmental factor (E factor). GI was found active in the ROMP of 3 without the need of protecting the hydroxy group and thus leading to pendent hydroxy functional polymers. Furthermore, for the first time, copolymers containing both LGO and HBO reactive moieties were prepared by random copolymerization of 1 and 3.