A study of mechanical properties of biobased epoxy network: Effect of addition of epoxidized soybean oil and poly(furfuryl alcohol)

A novel biobased thermoset interpenetrating network was introduced in this study. Epoxidized soybean oil (ESO) and poly(furfuryl alcohol) (PFA) were added to a commercial biobased epoxy resin. It was hypothesized that addition of ESO and PFA can decrease brittleness of bioepoxy resin and also increase biobased content. Mechanical properties of samples were evaluated using tensile and impact test. It was found that the addition of ESO and PFA increased notched Izod impact energy by 76.6%. This significant increase was related to incorporation of long flexible chains of ESO into the matrix. Hybridization of ESO and PFA in bioepoxy reduced tensile strength (around 70%), tensile modulus (around 90%), and glass transition temperature in comparison to neat bioepoxy. Tensile strength and modulus of hybridized system can be further improved by addition of natural fibers and the resultant composite may be considered as a good candidate for applications in which damping properties are important. Crosslink density was calculated using dynamic mechanical analysis and a decrease in crosslink density was observed in hybridized system. PFA domains were observed in the matrix using atomic force microscopy in peak force quantitative nano-mechanical mode and it revealed inhomogeneity in the crosslinked structure. (c) 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44352.