文献类型：期刊文献

英文题名：STUDY OF CHEMICAL MODIFICATION OF ALKALINE LIGNIN BY THE GLYOXALATION REACTION

作者：El Mansouri, Nour-Eddine[1,2,3];Yuan, Qiaolong[1,2];Huang, Farong[1,2]

机构：[1]E China Univ Sci & Technol, Sch Mat Sci & Engn, Key Lab Specially Funct Polymer Mat, Shanghai 200237, Peoples R China;[2]E China Univ Sci & Technol, Sch Mat Sci & Engn, Related Technol Minist Educ, Shanghai 200237, Peoples R China;[3]Univ Girona, Dept Chem Engn, LEPAMAP Grp, Girona 17071, Spain

年份：2011

卷号：6

期号：4

起止页码：4523

外文期刊名：BIORESOURCES

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000298119500066)】；

基金：The authors wish to thank the Commission for Universities and Research of the DIUiE of the Generalitat of Catalonia and Henkel KGaA for their support.

语种：英文

外文关键词：Glyoxalation; Hydroxymethylation; Alkaline lignin; Glyoxal; Wood adhesives

摘要：In this study, glyoxalated alkaline lignins with a non-volatile and non-toxic aldehyde, which can be obtained from several natural resources, namely glyoxal, were prepared and characterized for its use in wood adhesives. The preparation method consisted of the reaction of lignin with glyoxal under an alkaline medium. The influence of reaction conditions such as the molar ratio of sodium hydroxide-to-lignin and reaction time were studied relative to the properties of the prepared adducts. The analytical techniques used were FTIR and H-1-NMR spectroscopies, gel permeation chromatography (GPC), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Results from both the FTIR and H-1-NMR spectroscopies showed that the amount of introduced aliphatic hydroxyl groups onto the lignin molecule increased with increasing reaction time and reached a maximum value at 10 h, and after they began to decrease. The molecular weights remained unchanged until 10 h of reaction time, and then started to increase, possibly due to the repolymerization reactions. DSC analysis showed that the glass transition temperature (T-g) decreased with the introduction of glyoxal onto the lignin molecule due to the increase in free volume of the lignin molecules. TGA analysis showed that the thermal stability of glyoxalated lignin is not influenced and remained suitable for wood adhesives. Compared to the original lignin, the improved lignin is reactive and a suitable raw material for adhesive formulation.