麦草纤维复合胞间层和次生壁木质素的分离及其化学结构的研究  

Isolation and Characterization of Compound Middle Lamella Lignin and Secondary Wall Lignin from wheat Straws (Triticum aestivum CV Yangmai No.4)

作　　者：王忠[1] 邰瓞生[1] 李忠正[1] 

机构地区：[1]南京林业大学木材化学与工程学科组

出　　处：《中国造纸学报》1989年第1期16-23,共8页Transactions of China Pulp and Paper

摘　　要：本研究采用振动球磨的方法分离出麦草的复合胞间层术质素和次生壁术质素。结果表明,这两部分木质素在结构上有很大的差异。The characteristics of wheat straw lignin are different from that of wood. Previous work indicated that there was no topochemical effects on delignification when pulping wheat straw, but reactions with the compound middle lamella lignin are different from those with the secondary wall lignin. In order to study the characteristics of lignins in these two fiber regions, the method of controlled milling time was used to separate compound'middle lamella lignin (CMLL) and secondary wall lignin (SWL) in wheat straw. In the preparation of the two kinds of lignin, fiber samples were put in a ball mill and then milled for 20, 48, 96 hours respectively. After extracting with dioxahe-water, they were purified by the Lundquist' s method. The lignin fraction milled for 20 hours had lower carbohydrate contents but higher concentra, tion of lignin, therefore it was suggested to be lignin mainly from the compound middle lamella, whereas the lignin fraction of 96 hours milling time being mainly from the secondary wall. The molecular weights and distribution of these lignin fractions were detected with HPLC/GPC. The M_W of CMLL was nearly two times that of SWL. and the dispersity of CMLL was larger than that of SWL. The methoxyl content of SWL was significantly higher than that of CMLL. This indicated that more syringyl units were present in SWL. As wheat straw lignin was of GSH type, it followed that there ought to be more H units and G units in CMLL. These methoxylless structures would result in condensation in the 3-,5-positions of the aromatic rings. Total phenolic hydroxyl grouup content was higher in CMLL whereas carboxyl group content was higher in SWL. Alkaline nitrobenzene oxidation results showed that the S/V value of C M LL was obviously lower than that of SWL. This indicated that there was a large amount of G units in CMLL. The fact that total aldehyde yield of CM LL was much lower than that of SWL showed that more condensation structures being present in CMLL. CMLL had a shoulder around 315 nm in the UV spectra. This

关 键 词：麦草 纤维复合 木质素 分离 化学结构 研究 球磨 振动 

分 类 号：TS14[轻工技术与工程—纺织材料与纺织品设计] TQ323.6[轻工技术与工程—纺织科学与工程]