Renewable Furfural-Based\nSulfur-Bridged Epoxy Resins\nwith Excellent Adhesive Properties

The increasing interest in reducing the dependence on\nfossil-based\nresources by searching and replacing them with renewable biobased\nsources has intensified in both industrial and academic sectors. Especially,\nlignocellulose-based biomass can be utilized in the production of\nmany aromatic platform chemicals suitable as substitutes for known\nfossil-based chemicals. For example, cellulose-derived 5-(hydroxymethyl)furfural\nhas been utilized successfully for the aforementioned purposes. On\nthe other hand, hemicellulose-derived furfural has received rather\nminor attention, even though recent studies show various excellent\nresults in applications especially utilizing furfural. In this work,\ntwo novel furfural-derived epoxy resins were synthesized. Comparative\nstudies were conducted with commercially available and widely used\nfossil-based epoxy resin, diglycidyl ether of bisphenol A. Resins\nwere cured with methylhexahydrophthalic anhydride with optimized amounts\nof the 2-ethyl-4-methylimidazole initiator. Curing behaviors were\nstudied with differential scanning calorimetry while thermomechanical\nproperties were evaluated using dynamic mechanical analysis and thermal\nstabilities with thermogravimetric analysis. Adhesion strengths were\ntested with single-lap joint steel plate samples using a tensile tester.\nTensile testing was also carried out for dog-bone-shaped resin specimens.\nLastly, the water absorptions were evaluated through immersion in\nwater. Results showed that the synthesized bioresins have great potential\nto replace diglycidyl ether of bisphenol A in various applications.