Structure–property relationships of a bio-based reactive diluent in a bio-based epoxy resin

The monofunctional glycidyl ether of eugenol (GE) was used as a reactive diluent for the diglycidyl ether of diphenolate n-pentyl ester (DGEDP-Pe). Viscosities of GE and DGEDP-Pe are 25 mPa s and 11 Pa s, respectively. Compositions GE/DGEDP-Pe epoxy resins with 5, 10, 15, 20, and 30 wt % GE were analyzed for viscosity reductions and, subsequently, cured with isophorone diamine. The glassy modulus of cured GE/DGEDP-Pe epoxy resins remained between 2000 and 3000 MPa. The glass transition temperature decreased linearly, from 92 °C for neat DGEDP-Pe, with progressively higher loadings of GE to 53 °C at the highest GE loading of 30 wt %. The thermal stability decreased as GE loading increased with a maximum of 30 °C loss in the onset of degradation at 5 wt % mass loss. The role of GE as a reactive diluent is discussed and a range of loadings was determined to be suitable for a vacuum infusion epoxy resin system. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43635.