Bio-based furan polymers via ring opening polymerization

The extensive use of linear polyesters (PEs) in packaging, smart materials, clothing, and electronics is a testament to their remarkable qualities and versatility. PEs like poly(ethylene terephthalate) (PET), and poly(butylene terephthalate) (PBT) are among the most used in everyday life. However, the production and consumption of fossil-derived PEs come with certain critical issues such as the depletion of crude oil resources and environmental concerns related to their frequent low levels of biodegradability. [1] In addition, traditional polymerization strategies often require harsh reaction conditions and metal catalysts, with the consequent production of undesired by-products that need to be removed from the reaction mixture. [2] From these premises, our recent work has been focused on developing alternative synthetic strategies towards bio-based PEs via Ring Opening Polymerization (ROP) of macrocycles incorporating bio-based monomers, such as 2,5-furandicarboxylic acid dimethyl ester (FDME). The macrocycles were synthesized by reacting FDME with different diols such as tetraethylene glycol and hexaethylene glycol both via pseudo-high dilution condensation (PHDC) [3] and cyclo-depolymerization (CDP).[4] Subsequent ROP experiments were conducted both on the pure isolated macrocycles and on the macrocyles mixtures to achieve high molecular weight polyesters. Reaction conditions of the ROP such as catalyst, solvent, concentration and temperature were investigated, and efforts were made to recover and reuse solvents and catalysts when feasible. The structural characterization of the polymers obtained was carried out employing FTIR, 1H NMR, 13C NMR, TGA, GPC and DSC techniques.