Synthesis and Thermal Properties of Bio-Based Copolyesters from the Mixtures of 2,5- A nd 2,4-Furandicarboxylic Acid with Different Diols

Recent works highlighted how interesting are the properties of furan-based polyesters. Most of the attention has been focused on the homopolyester obtained with 2,5-furandicarboxylic acid and ethylene glycol, but other possibilities exist, which could help in tuning the final properties by carefully selecting the nature and proportion of the initial building blocks. This work reports the synthesis and properties (thermal stability, activation energy for thermal decomposition, glass transition temperature, and aptitude to crystallize) of three series of polyesters obtained by combining various amounts of two isomers of furandicarboxylic acid with different linear aliphatic diols, such as ethylene glycol, 1,3-propanediol, and 1,4-butanediol. This approach provided homopolymers and copolymers with high molecular weights, good thermal stability, broad processing windows, and a thermal behavior that can be tuned both in terms of glass transition temperature and crystallinity. In most cases, the mixtures of 2,5- A nd 2,4-isomers obtained during the Henkel disproportionation reaction can be directly used to synthetize furan-based copolyesters with good properties without the downstream processing typically performed to separate the isomers prior to polymerization, which may considerably reduce the time and costs for biomass valorization.