Defatted soyflour (53.4% protein content) was obtained from Yuxin Soybean Protein Co., Ltd, China. Poplar veneer with a
thickness of 1.5 mm and moisture content of 8–10% was purchased for the preparation of plywood. Epoxy resin (EPR) was a commercial product with the name of E-44, whose epoxide number was 0.41–0.47 and softening point was 12–201C. All other chemicals mentioned in this work were all of reagent grade