1 College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China; 2 Guangxi Fenglin Wood Industry Group Co. Ltd., Nanning 530031, China; 3 Dare Wood-based Panel Group Co. Ltd., Zhenjiang 212300, China
Abstract: In order to expand the application field of starch and reduce the free formaldehyde content of urea-formaldehyde resin adhesive, urea-dialdehyde starch-formaldehyde (UDSF) copolycondensation resin adhesive was prepared by copolycondensation of dialdehyde starch with urea and formaldehyde. The effects of the amount of dialdehyde starch, the first copolymerization time and the first urea ratio (F/U1) on the solid content, viscosity, water solubility, curing time and free formaldehyde content of the adhesives were investigated. By comparing with urea-starch-formaldehyde (USF), it was concluded that when the amount of dialdehyde starch was 0.075 mol, the first copolymerization time was 60 min and F/U1 was 1.5, the UDSF resin adhesive had better operational performance, faster curing rate, better environmental protection performance, bonding strength and water resistance to meet the requirements of class II plywood. Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and thermogravimetric analyzer (TGA) were used to compare UDSF resin adhesives and USF resin adhesives. The results showed that dialdehyde starch had higher reactivity with urea and formaldehyde than native starch, and the copolycondensation reaction was more sufficient. The polymerization degree and crosslinking of UDSF resin were significantly improved, making UDSF resin a continuous homogeneous system. It was explained the internal reasons of shortening curing time, decreasing free formaldehyde content, improving bonding strength and heat resistance of UDSF resin adhesive. At the same time, the decrease of free -OH and the increase of association -OH in UDSF resin verify the improvement of water resistance of UDSF resin adhesive.
1 Park B D, Jeong H W. International Journal of Adhesion and Adhesives, 2011, 31(6), 524. 2 Gu Jiyou. China Forest Products Industry, 2017, 44(1), 6(in Chinese). 顾继友. 林产工业, 2017, 44(1), 6. 3 Wu Zhigang, Du Guanben, Lei Hong, et al. Journal of Forestry Engineering, 2016, 1(1), 31(in Chinese). 吴志刚, 杜官本, 雷洪, 等. 林业工程学报, 2016, 1(1), 31. 4 Boran S, Usta M, Gümüşkaya E. International Journal of Adhesion and Adhesives, 2011, 31(7), 674. 5 Que Z, Furuno T, Katoh S, et al. Building and Environment, 2007, 42(3), 1257. 6 Zhang H, Zhang J, Song S, et al. Bioresources, 2011, 6(4), 4430. 7 Park B D, Kang E C, Park J Y. Journal of Applied Polymer Science, 2008, 110(3), 1573. 8 Park B D, Lee S M, Roh J K. European Journal of Wood and Wood Products, 2009, 67(1), 121. 9 Wu Xinshu, Zhou Xiaxing, Tang Yanhua, et al. Chemistry and Adhesion, 2018, 40(5), 367(in Chinese). 吴馨姝, 周吓星, 汤艳华, 等. 化学与黏合, 2018, 40(5), 367. 10 Tohmura S, Inoue A, Sahari S H. Journal of Wood Science, 2001, 47(6), 451. 11 Halvarsson S, Edlund H, Norgren M. Industrial Crops and Products, 2008, 28(1), 37. 12 Zhang Y, Yang C, Zheng J, et al. Iranian Polymer Journal, 2015, 24(1), 13. 13 Zhu X, Xu E, Lin R, et al. Journal of Applied Polymer Science, 2014, 131(9), 40202. 14 Zhang Xichao, Zhang Yanhua, Tan Haiyan, et al. Journal of Northeast Forestry University, 2015, 43(12), 103(in Chinese). 张希超, 张彦华, 谭海彦, 等. 东北林业大学学报, 2015, 43(12), 103. 15 Mu C, Liu F, Cheng Q, et al. Macromolecular Materials and Enginee-ring, 2010, 295(2), 100. 16 Li P, Wu Y, Zhou Y, et al. International Journal of Biological Macromolecules, 2019, 127, 12. 17 Liu Wenjie, Zuo Yingfeng, Wu Yiqiang, et al. Materials Review B: Research Papers, 2017, 31(4), 41(in Chinese). 刘文杰, 左迎峰, 吴义强, 等. 材料导报:研究篇, 2017, 31(4), 41. 18 Erickson R L, Barkmeier W W, Latta M A. Dental Materials, 2009, 25(11), 1459. 19 Kamke F A, Lee J N. Wood and Fiber Science, 2007, 39(2), 205. 20 Zou Yijia, Chen Yuhe, Wu Zaixing, et al. Chemistry and Industry of Forest Products, 2013, 33(5), 127(in Chinese). 邹怡佳, 陈玉和, 吴再兴. 林产化学与工业, 2013, 33(5), 127. 21 Zheng Yuansong, Guan Mingjie, Zhang Zhiwei, et al. Journal of Forestry Engineering, 2017, 2(3), 28(in Chinese). 郑源松, 关明杰, 张志威, 等. 林业工程学报, 2017, 2(3), 28. 22 Gu Jiyou. Adhesives and coatings, China Forestry Publishing House, China, 2012. 顾继友. 胶黏剂与涂料,中国林业出版社, 2012. 23 Zuo Y, Gu J, Tan H, et al. Journal of Adhesion Science and Technology, 2014, 28(5), 479. 24 Zuo Y, Liu W, Xiao J, et al. International Journal of Biological Macromolecules, 2017, 103, 1257.