Tailoring Bio-Based Epoxy-Anhydride Thermosets: A Comprehensive Study on the Epoxidized Sucrose Soyate and Dodecenyl Succinic Anhydride System

Abstract

This study investigated the development and optimization of bio-based thermosets synthesized from epoxidized sucrose soyate (ESS) and dodecenyl succinic anhydride (DDSA). It explored how variations in the stoichiometric ratio of epoxide-to-anhydride (R) and catalyst concentration influence the chemical, thermal, and mechanical properties of these sustainable thermosets. A multi-analytical approach was used to optimize curing conditions and characterize the resulting thermosets. The most effective curing process involved a two-stage protocol: initial curing at 120°C, followed by post-curing at 150°C, which enabled achieving the desired properties in a shorter period while minimizing energy consumption. Non-stoichiometric ratios demonstrated superior performance, with the optimal elasticity-strength balance achieved at R = 0.75 and maximum tensile toughness at R = 1.00. The thermosets exhibited excellent thermal stability, with initial decomposition temperatures exceeding 270°C in both oxidative and inert environments. Quaternary onium salt (BV-CAT7) was found to be the most efficient catalyst, with 3 wt % concentration at R = 0.75, providing optimal glass transition temperature, crosslink density, and thermal stability. Coating performance evaluations showed that formulations with R between 0.75 and 1.00, containing a 3% BV-CAT7, demonstrated superior performance in hardness, flexibility, solvent resistance, and adhesion. Finally, by systematically exploring the tunability and performance limits of ESS-DDSA systems, this research contributes to the broader goal of developing high-performance, sustainable alternatives to conventional petroleum-based thermosets, tailored for specific industrial applications.