Understanding the structure-property relationship of anhydride-cured epoxidized vegetable oils: Modeling and molecular dynamics simulation

The development of high-performance thermosetting resins derived from epoxidized vegetable oil (EVO) has received significant attention in terms of the development of low-carbon economies. In this work, the all-atomic cross-linked models of anhydride-cured EVO were constructed and five cross-linking pathways involving distinct cure reactions were considered in the modelling process. The evolution of the number of distinct cure reactions and reactive groups of the cross-linked network under each pathway were monitored. The effects of the type of cure reaction, cure reaction probability, epoxy functionality of monomer, molar ratio of anhydride to epoxy, and anhydride structure on mass density, gelation transition, bulk properties, thermal properties, and mechanical properties of EVO-based thermosets were investigated in detail. The results show that the network exhibited minor difference in cure reactions but apparent thermo-mechanical properties of the thermosets. Etherification of epoxy groups and dehydration condensation caused the unfavorable thermo-mechanical properties. The glass transition temperature (T_g) is most affected by the molar ratio of anhydride to epoxy; whereas the Young's modulus is sensitive to the epoxy functionality of monomer. It is expected that the current work provides deep insights into the network formation and performance development of anhydride-cured EVO thermosets.