Negi Arvind
Faculty of Educational Science, University of Helsinki, 00014 Helsinki, Finland.
Polymers (Basel). 2024 Dec 27;17(1):36. doi: 10.3390/polym17010036.
Cellulose is a homopolymer composed of β-glucose units linked by 1,4-beta linkages in a linear arrangement, providing its structure with intermolecular H-bonding networking and crystallinity. The participation of hydroxy groups in the H-bonding network results in a low-to-average nucleophilicity of cellulose, which is insufficient for executing a nucleophilic reaction. Importantly, as a polyhydroxy biopolymer, cellulose has a high proportion of hydroxy groups in secondary and primary forms, providing it with limited aqueous solubility, highly dependent on its form, size, and other materialistic properties. Therefore, cellulose materials are generally known for their low reactivity and limited aqueous solubility and usually undergo aqueous medium-assisted pretreatment methods. The cationization of cellulose materials is one such example of pretreatment, which introduces a positive charge over its surface, improving its accessibility towards anionic group-containing molecules or application-targeted functionalization. The chemistry of cationization of cellulose has been widely explored, leading to the development of various building blocks for different material-based applications. Specifically, in coloration applications, cationized cellulose materials have been extensively studied, as the dyeing process benefits from the enhanced ionic interactions with anionic groups (such as sulfate, carboxylic groups, or phenolic groups), minimizing/eliminating the need for chemical auxiliaries. This study provides insights into the chemistry of cellulose cationization, which can benefit the material, polymer, textile, and color chemist. This paper deals with the chemistry information of cationization and how it enhances the reactivity of cellulose fibers towards its processing.
纤维素是一种均聚物，由β-葡萄糖单元通过1,4-β键以线性排列连接而成，其结构具有分子间氢键网络和结晶性。羟基参与氢键网络导致纤维素的亲核性较低至中等，不足以进行亲核反应。重要的是，作为一种多羟基生物聚合物，纤维素具有高比例的仲羟基和伯羟基，这使得它在水中的溶解度有限，且高度依赖于其形态、大小和其他物质特性。因此，纤维素材料通常以其低反应性和有限的水溶性而闻名，并且通常需要进行水介质辅助预处理方法。纤维素材料的阳离子化就是这样一种预处理示例，它在其表面引入正电荷，提高其对含阴离子基团分子的可及性或针对应用的功能化。纤维素阳离子化的化学过程已得到广泛探索，从而开发出用于不同材料基应用的各种构建模块。具体而言，在染色应用中，阳离子化纤维素材料已得到广泛研究，因为染色过程受益于与阴离子基团（如硫酸根、羧基或酚羟基）增强的离子相互作用，从而减少/消除了对化学助剂的需求。本研究深入探讨了纤维素阳离子化的化学过程，这对材料、聚合物、纺织和颜色化学家有益。本文论述了阳离子化的化学信息以及它如何增强纤维素纤维在加工过程中的反应性。
