Department of Chemistry, Sri Sai University, Palampur 176061, India.
São Carlos Institute of Chemistry, Macromolecular Materials and Lignocellulosic Fibers Group, Center for Science and Technology of BioResources, University of São Paulo, C.P. 780, São Carlos, SP CEP 13560-970, Brazil.
Int J Biol Macromol. 2021 Jul 1;182:1554-1581. doi: 10.1016/j.ijbiomac.2021.05.119. Epub 2021 May 23.
Cellulose nanocrystals (CNCs) have attracted great interest from researchers from academic and industrial areas because of their interesting structural features and unique physicochemical properties, such as magnificent mechanical strength, high surface area, and many hydroxyl groups for chemical modification, low density, and biodegradability. CNCs are an outstanding contender for applications in assorted fields comprehensive of, e.g., biomedical, electronic gadgets, water purifications, nanocomposites, membranes. Additionally, a persistent progression is going on in the extraction and surface modification of cellulose nanocrystals to fulfill the expanding need of producers to fabricate cellulose nanocrystals-based materials. In this review, the foundation of nanocellulose that emerged from lignocellulosic biomass and recent development in extraction/preparation of cellulose nanocrystals and different types of cellulose nanocrystal surface modification techniques are summed up. The different sorts of cellulose modification reactions that have been discussed are acetylation, oxidations, esterifications, etherifications, ion-pair formation, hydrogen bonding, silanization, nucleophilic substitution reactions, and so forth. The mechanisms of surface functionalization reactions are also introduced and considered concerning the impact on the reactions. Moreover, the primary association of cellulose and different forms of nanocellulose has likewise been examined for beginners in this field.
纤维素纳米晶体（CNCs）因其有趣的结构特征和独特的物理化学性质，如出色的机械强度、高比表面积和许多可用于化学修饰的羟基、低密度和可生物降解性，引起了学术界和工业界研究人员的极大兴趣。CNCs 是在包括生物医学、电子设备、水净化、纳米复合材料、膜等在内的各个领域应用的杰出竞争者。此外，对纤维素纳米晶体的提取和表面改性的持续研究正在进行，以满足生产商制造基于纤维素纳米晶体的材料的不断增长的需求。在这篇综述中，总结了来源于木质纤维素生物质的纳米纤维素的基础以及纤维素纳米晶体的提取/制备和不同类型的纤维素纳米晶体表面改性技术的最新发展。讨论了不同类型的纤维素改性反应，如乙酰化、氧化、酯化、醚化、离子对形成、氢键、硅烷化、亲核取代反应等。还介绍了表面功能化反应的机制，并考虑了它们对反应的影响。此外，还针对该领域的初学者，对纤维素和不同形式的纳米纤维素的主要结合进行了考察。
