The Effect of Soy-Flour Mesh Size and its Adhesive Acidity Changes on Shear Strength of Plywood

In this study the effect of soy flour mesh size and the change of adhesive’s acidity made from its on shear strength of plywood was evaluated. For this aim, soy flour particles classified in three levels mesh size (60, 100 and 140 mesh) by ASTM Sieves. Also, the acidity of soy adhesives changed by sodium hydroxide and sulfuric acid. Results showed that the mesh size of soy flour effected on shear strength of plywood made from soy flour adhesives. The shear strength of plywood made from soy flour with 140 mesh was higher than other specimens. Also, the increase of soy flour adhesive’s acidity by sodium hydroxide resulted in increase of shear strength of plywood. The shear strength of plywood made from soy adhesives compare to plywood made from urea formaldehyde resin was low but it was acceptable according to EN-314 standard.