Effects of Oxidation Cassava Starch Content on Urea-formaldehyde Resin Performance

Two kinds of urea-formaldehyde resin was synthesized with F : U molar ratio 1.0 and 1.5, to which different oxidation cassava starch content was added at the end of reaction period. The basic performance, curing characteristics and glued strength of resins were studied. The results showed that oxidation cassava starch could increase the solid content and viscosity of resins, but the curing characteristic obviously changed with different F : U molar ratio and oxidation cassava starch content. When n_F : n_U=1.0, resin curing time was shorted by increasing oxidation cassava starch content. Within 5% cassava starch content, the initial curing temperature was lower compared with pure UF, the wet strength of plywood was first increased then down. When n_F : n_U=1.5, the curing time changed as the n_F : n_U=1.0, while the initial curing temperature was all higher than pure UF, thus the dry and wet strength were increased with the increase of oxidation cassava starch usage. At last, by considering integrated performance of resin, when n_F : n_U=1.0, the mass ratio of oxidation cassava starch and urea was 3%, the resin performance was the best. And when n_F : n_U=1.5, mass ratio of that was 5% was the best.