摘要
为解决UF树脂和单宁树脂存在的问题,利用2种树脂各自优点,制备了UF树脂+单宁树脂共混胶黏剂。通过红外光谱、核磁共振碳谱和质谱对胶黏剂分子结构进行研究,应用差示扫描量热仪和凝胶时间研究胶黏剂固化行为,同时对其胶黏剂黏度、板材胶合性能及甲醛释放进行了分析。结果表明:单宁树脂的加入对共混胶黏剂的结构影响不大,仍是以亚甲基键连接;相对于UF树脂而言,单宁树脂的加入虽然延长了共混胶黏剂的凝胶时间,但显著降低了板材的甲醛释放量,其中单宁树脂添加量为5%和pH=7时甲醛释放量降低最显著;不同pH条件下合成的单宁树脂对共混胶黏剂性能影响较大,pH=7和9时共混胶黏剂的胶合强度较优,pH=4.6和pH=11对胶合性能造成负面影响,降低了胶合强度;不同比例(5%、15%、25%)单宁树脂的加入对共混胶黏剂胶合强度影响较大,随着单宁树脂比例的增加,共混胶黏剂的胶合强度逐步降低;经过滑动弧冷等离子体对单板处理后,共混胶黏剂对胶合板的胶合性能得到改善,有了一定的耐热水强度。
To solve the problem of UF and tannin resin,this study prepared the adhesive by mixing UF resin and tannin resin to make maximization of the advantages of these 2 resins.Infrared spectroscopy(FT-IR),nuclear magnetic resonance carbon spectroscopy(13C NMR)and mass spectrometry(MS)were used to study the molecular structure of the hybrid adhesive;differential scanning calorimetry(DSC)and the gel time measurement were used to demonstrate the curing behavior;besides,and the viscosity of the hybrid adhesives and its bonding quality as well as formaldehyde emission of the panels were also measured.The results show that the addition of tannin resin had little effect on the structure of the hybrid adhesive,which still connected by methylene bond;compared with UF resin,the addition of tannin resin extended the gel time of the hybrid adhesive,but significantly reduced the formaldehyde emission of the panels,among the sample of panels,the tannin resin content on 5%and pH=7have maximum reduction for formaldehyde emission;the tannin resin synthesized under different pH conditions has a greater impact on the properties of the hybrid adhesive,that is,when pH=7 and 9,the hybrid adhesive has better bonding strength,and pH=4.6 and pH=11 negatively affect the bonding performance;the addition of tannin resin in different proportions,includes 5%,15%and 25%,has a greater impact on the bonding strength of the hybrid adhesive,that the bonding strength of the hybrid adhesive gradually reduces with the proportion of tannin resin increasing.After the veneer was treated by the sliding arc cold plasma,the shear strength of the plywood for hybrid adhesives have significantly improved that have the hot water resistance strength.
作者
彭晋达
邓霜琪
廖岽森
吴海柱
周晓剑
Peng Jinda;Deng Shuangqi;Liao Dongsen;Wu Haizhu;Zhou Xiaojian(Yunnan Provincial Key Laboratory of Wood Adhesives and Glued Products,Southwest Forestry University,Kunming Yunnan 650233,China)
出处
《西南林业大学学报（自然科学）》
CAS
北大核心
2022年第6期140-150,共11页
Journal of Southwest Forestry University：Natural Sciences
基金
国家自然科学基金项目(31971595)资助
云南省基础研究专项重点项目(202101AS070008)资助
云南省中青年学术和技术带头人后备人才项目(2019HB026)资助
高等学校学科创新引智计划(D21027)资助。
关键词
共混胶黏剂
化学结构
甲醛
冷等离子体
hybrid adhesive
chemical structure
formaldehyde
cold plasma
