氧化淀粉改性脲醛树脂的制备及性能1）

摘要

We modified urea-formaldehyde resin ( UF) by oxidized corn starch , studied the effect of oxidized starch addition on the properties of UF .To obtain the best optimal conditions , we evaluated bonding strength of plywood and free formalde-hyde content of UF resin and plywood .The free formaldehyde content of plywood and UF resin decreased .And the oxidized starch added was beneficial for improving bonding strength of plywood .The optimal condition to prepare UF with best per-formance was with the oxidized starch addition of 2%( the mass ratio of oxidized starch to urea was 2∶100 ) .Under this condition, the free formaldehyde contents of modified UF resin and plywood were 0.23%and 0.44 mg· L-1, respectively. Those corresponded to the E 0 level of GB/T 9846.3-2004.The bonding performance of the plywood was excellent , and the dry and wet bonding strength met the Ⅱplywood requirements of GB/T 9846.5-2004 .%采用氧化淀粉改性脲醛树脂，考查氧化淀粉添加比例对脲醛树脂性能的影响，并对胶合板的胶合强度和游离甲醛释放量进行了测试，以确定最佳的工艺条件。实验结果表明：氧化淀粉的加入明显降低了胶合板及脲醛树脂溶液中的游离甲醛释放量，较好地提高了胶合板的胶合强度。当氧化淀粉的添加量为2％（m（氧化淀粉）∶m（尿素）＝2∶100）时，改性脲醛树脂胶黏剂中液体游离甲醛质量分数0．23％，合成的胶合板中游离甲醛质量浓度0．44 mg· L－1，达到GB／T 9846．3—2004中E0级要求，且胶接性能良好，干强度和湿强度均达到了GB／T 9846．5—2004Ⅱ类胶合板的标准。