INRAE, UR BIA, F-44316 Nantes, France.
INRAE, UR BIA, F-44316 Nantes, France; Université de Lille, UMR-CNRS 8207, UMET, F-59652 Villeneuve d'Ascq, France.
Carbohydr Polym. 2022 Sep 1;291:119599. doi: 10.1016/j.carbpol.2022.119599. Epub 2022 May 10.
Fibre bundles are groups of elementary fibres glued together thanks to the middle lamella, and are the main fraction in plant fibre composites. In this study, relationship between the mechanical properties of flax fibre bundles, chemical composition and cellulose structure were investigated. To do so, a sequential biopolymer extraction was implemented. Fibre bundles were first depectinated by oxalate extraction, and then the hemicelluloses were extracted by LiCl/dimethyl sulfoxide (DMSO) and KOH. The oxalate extract consisted of homogalacturonans and type I rhamnogalacturonans, while the LiCl extract was composed mainly of glucomannans and the KOH extract of xyloglucans. The KOH stage resulted in the appearance of cellulose II in flax bundles. The extraction of pectin and hemicelluloses led to the disappearance of the middle lamella concomitant with a decrease in the tensile Young's modulus and maximum strength. Finally, the fibre bundle composition, ultrastructure and mechanical properties are discussed together in view of the thin middle lamella.
纤维束是通过中层黏合在一起的基本纤维群，是植物纤维复合材料的主要成分。本研究旨在探讨亚麻纤维束的力学性能与其化学成分和纤维素结构之间的关系。为此，我们采用了顺序生物聚合物提取法。首先通过草酸盐提取将纤维束脱胶，然后用氯化锂/二甲基亚砜（DMSO）和 KOH 提取半纤维素。草酸盐提取物主要由同质半乳糖醛酸聚糖和 I 型鼠李半乳糖醛酸聚糖组成，而 LiCl 提取物主要由葡甘露聚糖组成，KOH 提取物则主要由木葡聚糖组成。KOH 处理阶段导致亚麻纤维束中纤维素 II 的出现。果胶和半纤维素的提取导致中层黏合的消失，同时拉伸杨氏模量和最大强度降低。最后，根据薄中层黏合的特点，讨论了纤维束的组成、超微结构和力学性能。
