Synthesis of a bio-based unsaturated polyester resin from 2,5-furan dicarboxylic acid and isosorbide blended with a bio-based reactive diluent synthesized from 2,5-furandimethanol

A new bio-based unsaturated polyester resin was blended with a bio-based reactive diluent and evaluated. Furan-based monomers were selected as the main monomers in both the resin and the bio-based reactive diluent to enhance thermomechanical properties and address solubility issues typically seen in bio-based resins and diluents. The resin was synthesized from 2,5-furan dicarboxylic acid, isosorbide, and glycerol, and the resulting polymer intermediate was then end-capped with methacrylic anhydride to introduce reactive sites for cross-linking reaction. The resin was then mixed with either different percentages of bio-based reactive diluent (2,5-bis(hydroxy-methyl) furan methacrylate) or with styrene to study the thermomechanical and rheological behavior of obtained resins. FT-IR, 13 C-NMR, and 1 H-NMR were used to determine the chemical structure of the bio-based reactive diluent. The thermomechanical properties of resin containing bio-based reactive diluent or styrene are characterized and compared by DMA, TGA, and DSC. The synthesized resin had good solubility in the bio-based reactive diluent but not in the styrene. The different mixtures of resin and bio-based reactive diluent showed glass transition temperatures ranging from 166 °C to 174 °C, which was higher than the commercial fossil-based unsaturated polyester resin used as a reference in this study. With thermal and mechanical properties comparable to commercial petroleum-based thermosets, these bio-based resins are promising candidates for high-performance composites, coatings, and other thermoset-based applications.