Nonedible Thevetia peruviana Oil for the Synthesis of Biobased Thermosets and Vitrimers with Tunable Mechanical Properties

Current attempts to replace fossil-derived materials with vegetable oils for polymer production mainly rely on edible oils. This approach raises sustainability concerns due to potential food security risks. This report introduces the first in-depth examination of Thevetia peruviana oil (TPO) epoxidation, an easily accessible nonedible vegetable oil, utilizing diverse acidic ion-exchange resins as catalysts. It is followed by the development of vitrimers based on epoxidized oil (ETPO) with various dicarboxylic acid hardeners. Amberlite IRC120H emerged as the most effective catalyst for the epoxidation of the oil, allowing for repeated catalyst reusability for up to five cycles. An impressive relative oxirane conversion of 98.9% was achieved after optimization. DSC analysis revealed that among the diacids, 2,2′-dithiodibenzoic acid (DTBZ) has the lowest activation energy with ETPO. Additionally, the ETPO–DTBZ-based thermosets displayed exceptional solvent resistance and thermal stability, indicative of a high degree of cross-linked networks within the system. Mechanical analyses revealed that all aliphatic hardeners resulted in soft materials, while DTBZ resulted in thermosets with tensile stress and modulus of 15 and 843 MPa, respectively. Consequently, DTBZ–ETPO thermosets were successfully recycled, repaired, and reshaped with minimal changes in the mechanical properties. The shape memory of the thermosets was also established.