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On the interaction of softwood hemicellulose with cellulose surfaces in relation to molecular structure and physicochemical properties of hemicellulose.
Soft Matter ( IF 3.4 ) Pub Date : 2020-07-07 , DOI: 10.1039/d0sm00264j
Polina Naidjonoka 1 , Monica Arcos Hernandez , Gunnar K Pálsson , Frank Heinrich , Henrik Stålbrand , Tommy Nylander
Affiliation  

The substantial part of the water-soluble hemicellulose fraction, obtained when processing cellulose to produce paper and other products, has so far been discarded. The aim of this work is to reveal the interfacial properties of softwood hemicellulose (galactoglucomannan, GGM) in relation to their molecular and solution structure. In this study the sugar composition of GGM was characterised by chemical analysis as well as 1D and 2D NMR spectroscopy. Previously it has been demonstrated that hemicellulose has high affinity towards cellulose and has the ability to alter the properties of cellulose based products. This study is focused on the interactions between hemicellulose and the cellulose surface. Therefore, adsorption to hydrophobized silica and cellulose surfaces of two softwood hemicellulose samples and structurally similar seed hemicelluloses (galactomannans, GMs) was studied with ellipsometry, QCM-D and neutron reflectometry. Aqueous solutions of all samples were characterized with light scattering to determine how the degree of side-group substitution and molecular weight affect the conformation and aggregation of these polymers in the bulk. In addition, hemicellulose samples were studied with SAXS to investigate backbone flexibility. Light scattering results indicated that GM polymers form globular particles while GGMs were found to form rod-like aggregates in the solution. The polysaccharides exhibit higher adsorption to cellulose than on hydrophobic surfaces. A clear correlation between the increase in molecular weight of polysaccharides and increasing adsorbed amount on cellulose was observed, while the adsorbed amount on the hydrophobic surface was fairly independent of the molecular weight. The obtained layer thickness was compared with bulk scattering data and the results indicated flat conformation of the polysaccharides on the surface.

中文翻译:

关于软木半纤维素与纤维素表面的相互作用与半纤维素的分子结构和理化性质有关。

迄今为止,已经丢弃了在处理纤维素以生产纸和其他产品时获得的大部分水溶性半纤维素级分。这项工作的目的是揭示软木半纤维素(半乳葡甘露聚糖,GGM)与其分子和溶液结构有关的界面特性。在这项研究中,通过化学分析以及1D和2D NMR光谱对GGM的糖成分进行了表征。先前已证明半纤维素对纤维素具有高亲和力,并具有改变基于纤维素的产品的性能的能力。这项研究的重点是半纤维素和纤维素表面之间的相互作用。因此,用椭偏仪,Q​​CM-D和中子反射仪研究了两个软木半纤维素样品和结构相似的种子半纤维素(半乳甘露聚糖,GMs)在疏水化二氧化硅和纤维素表面的吸附。用光散射表征所有样品的水溶液,以确定侧基取代度和分子量如何影响这些聚合物在本体中的构象和聚集。此外,用SAXS研究了半纤维素样品,以研究骨架的柔韧性。光散射结果表明,GM聚合物形成球形颗粒,而GGM被发现在溶液中形成棒状聚集体。与疏水表面相比,多糖对纤维素的吸附更高。观察到多糖分子量的增加与纤维素上吸附量的增加之间存在明显的相关性,而疏水表面上的吸附量与分子量相当无关。将获得的层厚度与本体散射数据进行比较,结果表明多糖在表面上呈平坦构型。
更新日期:2020-08-05
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