氯化锌对单宁-尿素-甲醛(TUF)共缩聚树脂性能的影响  

Effect of Zinc Chloride on the Properties of Tannin-Urea-Formaldehyde Copolymerization Resin

作　　者：彭晋达 廖岽森 晏畅 杨福仙 张培贵 杜官本[1] 周晓剑[1] PENG Jin-da;LIAO Dong-sen;YAN Chang;YANG Fu-xian;ZHANG Pei-gui;DU Guan-ben;ZHOU Xiao-jian(Yunnan Key Laboratory of Wood Adhesives and Glued Products,Southwest Forestry University,Kunming 650224,Yunnan,China)

机构地区：[1]西南林业大学,云南省木材胶黏剂及胶合制品重点实验室,云南昆明650224

出　　处：《西北林学院学报》2023年第5期228-234,共7页Journal of Northwest Forestry University

基　　金：国家自然科学基金(NSFC 31971595);云南省基础研究计划项目(202101AS070008);云南省“兴滇人才”支持计划-青年人才。

摘　　要：针对单宁-尿素-甲醛(TUF)树脂出现的热压温度高、热压时间长的问题,采用二价金属盐-氯化锌对TUF树脂进行加速固化。从探究氯化锌加入比例对凝胶时间和胶合强度、降低固化剂用量的作用、在不同热压参数条件下的胶合强度表现、甲醛释放量等各方面的影响去探讨氯化锌加入的改性效果。借助傅里叶红外光谱分析(FT-IR)、差示扫描量热法(DSC)和热重分析(TG)来分析树脂结构变化以及热行为。结果表明,氯化锌的加入显著缩短了TUF树脂的凝胶时间,促进了树脂固化,2%的氯化锌添加使热水强度提升了31.5%,同时甲醛释放量降低了24%,但无法减少固化剂的用量;3%的氯化锌添加使板材耐沸水强度达到0.72 MPa,提升了148%。此外,在热压工艺测试中,2%的氯化锌加入极大地促进了交联固化,在140℃和8 min条件下,2%氯化锌试验组热水强度相对于在180℃和8 min条件下无氯化锌添加对照组提升了28%。FT-IR分析结果表明,氯化锌的加入能与单宁形成配位键,从而加速交联固化。DSC和TG分析从侧面佐证了TUF树脂反应位点增多、促进固化交联的结论。In order to solve the problems in the application of tannin-urea-formaldehyde(TUF)resin,such as high temperature and long curing time during hot-pressing process,this study used zinc chloride,a divalent metal salt to accelerate the curing of the resin.The effects of modification with ZnCl_(2)were characterized by gelation time,bonding strength,the effect of reducing the curing agent addition,and the bonding strength in different hot-pressing parameters.Besides,Fourier transform infrared spectroscopy(FT-IR),differential scanning calorimetry(DSC)and thermogravimetric analysis(TG)were used to analyze the resin structure variations and thermal behaviors.The results showed that the gelation time of TUF resin was reduced significantly with the addition of ZnCl_(2),the resin curing was also significantly accelerated.The bonding strength in 63℃water increased by 31.5%compared with control specimen with the addition of 2%ZnCl_(2),meanwhile the formaldehyde emission decreased by 24%.Furthermore,the bonding strength of plywood in boiling water reached to 0.71 MPa with 3%ZnCl_(2)addition with an increment extent of 148%.Moreover,the addition of 2%ZnCl_(2)greatly promoted the cross-linking and gelation curing.FT-IR analysis showed that the addition of ZnCl_(2)could form coordination bonds in tannins,thereby leading to fast resin curing and crosslinking.DSC and TG analysis corroborated the conclusion that TUF resin increased the reaction sites and promoted curing and crosslinking.In general,ZnCl_(2)added to TUF resin can accelerate the curing rate and cross-linking extent.

关 键 词：氯化锌 TUF树脂 热压工艺 胶合强度 树脂性能 

分 类 号：S781.7[农业科学—木材科学与技术]