Thermal and mechanical properties of sorbitol-based epoxy resin cured with quercetin and the biocomposites with wood flour

After a bio-based epoxy resin, sorbitol polyglycidyl ether (SPE) was mixed with a flavonoid, quercetin (QC) in tetrahydrofuran at an optimized epoxy/hydroxy ratio 1/1.2, the obtained SPE/QC solution was mixed with wood flour (WF), prepolymerized at 150 degrees C, and subsequently compressed at 170 degrees C for 3 h to give SPE-QC/WF biocomposites (WF content:0, 20, 30, 40 wt %). The tan peak temperature of SPE-QC without WF (85.5 degrees C) was higher than that of SPE cured with conventional phenol novolac (81.0 degrees C). In addition, diglycidyl ether of bisphenol A cured with QC had a higher tan peak temperature (145.1 degrees C) than that cured with PN (90.8 degrees C). The tan peak temperatures (106113 degrees C) of SPE-QC/WF biocomposites were significantly higher than that of SPE-QC. The tensile modulus of SPE-QC/WF biocomposites increased with increasing WF content. A lower wavenumber shift of carbonyl stretching absorption peak in the FTIR spectrum of SPE-QC/WF as compared with that of SPE-QC suggested that hydroxy group of woody component forms hydrogen bonding with carbonyl group of quercetin moiety. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013