A tetrafunctional bio-based epoxy from isosorbide and succinic anhydride: synthesis, properties and DGEBA comparison

Abstract A novel tetrafunctional bio-based epoxy, ISSATE (Isosorbide-Succinic anhydride-Tetra epoxy), was synthesized from isosorbide and succinic anhydride and subsequently cured with the bio-based amine, 1,8- p -Menthanediamine (MTDA), to yield a solid thermoset. While ISSATE is a colorless, viscous liquid prior to curing, the resulting cured material exhibits a rigid, high-performance network. The cured ISSATE-MTDA system demonstrated a thermal decomposition temperature and tensile modulus comparable to those of conventional bisphenol A diglycidyl ether (DGEBA), which served as the reference. The flexible succinic segments in ISSAT lowered its glass transition temperature relative to DGEBA, however, the tetrafunctional design of ISSATE results in enhanced epoxy reactivity, tensile strength, and elongation at break due to an increased density of reactive sites and the synergistic effects of the bio-based components. Although ISSATE-MTDA system exhibits a slightly lower onset of thermal degradation compared to DGEBA, its overall decomposition temperature remains high, indicating robust thermal performance. These findings strongly support ISSATE as a promising, sustainable alternative to DGEBA-based resins, aligning with global efforts to reduce fossil fuels dependence and mitigate environmental impact.