Wheat straw Biolignin (TM) was used as a substitute of bisphenol-A in epoxy resin. Synthesis was carried out in alkaline aqueous media using polyethyleneglycol diglycidyl ether (PEGDGE) as epoxide agent. Structural study of Biolignin (TM) and PEGDGE was performed by solid-state C-13 NMR and gel permeation chromatography, respectively, before epoxy resin synthesis. Biolignin (TM) based epoxy resins were obtained with different ratios of Biolignin (TM) : PEGDGE and their structures were analyzed by solid-state 13C NMR. The crosslinking of PEGDGE with Biolignin (TM) was highlighted in this study. Properties of Biolignin (TM) based epoxy resins were analyzed by differential scanning calorimetry and dynamic load thermomechanical analysis as well as compared with those of a bisphenol-A epoxy-amine resin. Depending on the epoxy resin formulation, results confirmed the high potential of Biolignin (TM) as a biosourced polyphenol used in epoxy resin applications. (C) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013