Properties and curing kinetics of epoxy resin toughened by dimer acid diglycidyl ester

In this work, dimer acid diglycidyl ester (DAGE) was synthesized from the dimer acid via a two-step method and applied as a bio-based toughener for bisphenol A epoxy resin (DGEBA). Mechanical tests demonstrated that DAGE had significant effects on the flexibility of DGEBA. When 5 wt% DAGE was incorporated into DGEBA system, there was an enhancement of 2.56 times of the impact strength. Meanwhile, the tensile strength and elongation at break increased by 17.2 % and 13.4 %, respectively. In addition, the curing behavior of DAGE/DGEBA system was kinetically modeled based on non-isothermal DSC data. The incorporation of DAGE has little effect on the apparent activation energy of the system. Moreover, the curing process can be accurately described by the Sestak-Berggren model. The bio-derived DAGE holds great potential for practical applications.