Curing kinetics of bio-based epoxy resin based on epoxidized soybean oil and green curing agent

New thermoset with a high bio-based content was synthesized by curing epoxidized soybean oil (ESO) with a green curing agent maleopimaric acid catalyzed by 2-ethly-4-methylimidazole. Non-isothermal differential scanning calorimetry and a relatively new integral isoconversional method were used to analyze the curing kinetic behaviors and determine the activation energy (E-a). The two-parameter Sestak-Berggren autocatalytic model was applied in the mathematical modeling to obtain the reaction orders and the pro-exponential factor. For anhydride/epoxy group molar ratio equal to 0.7, E-a decreased from 82.70 to 80.17 kJ/mol when increasing the amount of catalyst from 0.5 to 1.5 phr toward ESO. The reaction orders m and n were 0.4148 and 1.109, respectively. The predicted non-isothermal curing rates of Sestak-Berggren model matched perfectly with the experimental data. (c) 2016 American Institute of Chemical Engineers AIChE J, 63: 147-153, 2017