摘要
为扩大淀粉的应用领域和减小脲醛树脂胶黏剂游离甲醛的含量,采用双醛淀粉与尿素、甲醛进行共缩聚反应,制得尿素-双醛淀粉-甲醛(UDSF)共缩聚树脂胶黏剂。考察了双醛淀粉用量、第一次共缩聚时间和第一次尿素比例(F/U1)对胶黏剂固体含量、黏度、水溶性、固化时间和游离甲醛含量的影响。并通过与尿素-淀粉-甲醛(USF)进行对比,得出双醛淀粉用量为0.075 mol,第一次共缩聚时间为60 min和F/U1为1.5时,所制得的UDSF树脂胶黏剂的使用操作性能较好、固化速率较快、环保性能较优、胶合强度和耐水性满足Ⅱ类胶合板要求。利用傅里叶变换红外光谱(FT-IR)、扫描电子显微镜(SEM)和热重测试仪(TGA)对UDSF树脂胶黏剂和对照样USF树脂胶黏剂进行了对比分析。结果表明,相比于原淀粉,双醛淀粉与尿素、甲醛反应活性更大,共缩聚反应更充分,显著提高了树脂的聚合度和交联度,使UDSF树脂成为连续的均相体系。解释了UDSF树脂胶黏剂固化时间缩短、游离甲醛含量降低、胶合强度和耐热性能提高的内在原因。同时UDSF树脂中游离-OH数量减少且缔合-OH数量增多,验证了UDSF树脂胶黏剂耐水性能的提高。
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.
作者
左迎峰
屠茹茹
吴义强
詹满军
陈秀兰
袁光明
ZUO Yingfeng;TU Ruru;WU Yiqiang;ZHAN Manjun;CHEN Xiulan;YUAN Guangming(College of Materials Science and Engineering,Central South University of Forestry and Technology,Changsha 410004,China;Guangxi Fenglin Wood Industry Group Co.Ltd.,Nanning 530031,China;Dare Wood-based Panel Group Co.Ltd.,Zhenjiang 212300,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2020年第8期172-178,共7页
Materials Reports
基金
湖南省科技重大专项(2017NK1010)
中南林业科技大学大学生科技创新项目。
关键词
双醛淀粉
脲醛树脂
共缩聚
胶黏剂
dialdehyde starch
urea formaldehyde resin
copolycondensation
adhesive
作者简介
左迎峰,中南林业科技大学,副教授。2014年毕业于东北林业大学,获工学博士学位。同年加入中南林业科技大学材料科学与工程学院工作,主要从事生物质复合材料及胶黏剂改性研究;吴义强,中南林业科技大学,教授,博士研究生导师,教育部“长江学者”特聘教授。主要从事木竹材加工利用和生物质复合材料研究,wuyq0506@126.com;袁光明,中南林业科技大学,教授,博士研究生导师,主要从事木材加工利用和生物质复合材料研究。ygm1237@163.com。
