Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan.
Adv Mater. 2021 Jul;33(28):e2000630. doi: 10.1002/adma.202000630. Epub 2020 Jul 19.
Nanocelluloses have unique morphologies, characteristics, and surface nanostructures, and are prepared from abundant and renewable plant biomass resources. Therefore, expansion of the use of CO -accumulating nanocelluloses is expected to partly contribute to the establishment of a sustainable society and help overcome current global environmental issues. Nanocelluloses can be categorized into cellulose nanonetworks, cellulose nanofibrils, and cellulose nanocrystals, depending on their morphologies. All of these materials are first obtained as aqueous dispersions. In particular, cellulose nanofibrils have homogeneous ≈3 nm widths and average lengths of >500 nm, and significant amounts of charged groups are present on their surfaces. Such charged groups are formed by carboxymethylation, C6-carboxylation, phosphorylation, phosphite esterification, xanthation, sulfate esterification, and C2/C3 dicarboxylation during the pretreatment of plant cellulose fibers before their conversion into cellulose nanofibrils via mechanical disintegration in water. These surface-charged groups in nanocelluloses can be stoichiometrically counterion-exchanged into diverse metal and alkylammonium ions, resulting in surface-modified nanocelluloses with various new functions including hydrophobic, water-resistant, catalytic, superdeodorant, and gas-separation properties. However, many fundamental and application-related issues facing nanocelluloses must first be overcome to enable their further expansion.
纳米纤维素具有独特的形态、特性和表面纳米结构，由丰富且可再生的植物生物质资源制备而成。因此，预计扩大 CO 蓄积纳米纤维素的使用将有助于部分建立可持续社会，并有助于解决当前的全球环境问题。纳米纤维素可根据其形态分为纤维素纳米网络、纤维素纳米纤维和纤维素纳米晶。所有这些材料最初都是以水性分散体的形式获得的。特别是，纤维素纳米纤维具有均匀的 ≈3nm 宽度和超过 500nm 的平均长度，并且其表面存在大量的带电基团。这些带电基团是通过植物纤维素纤维在转化为纤维素纳米纤维之前的预处理过程中的羧甲基化、C6-羧化、磷酸化、膦酸酯化、黄原酸化、硫酸酯化和 C2/C3 二羧化形成的。纳米纤维素中的这些表面带电基团可以通过化学计量的反离子交换成各种金属和烷基铵离子，从而得到具有各种新功能的表面改性纳米纤维素，包括疏水性、耐水性、催化性、超除味剂和气体分离性能。然而，纳米纤维素还面临许多基础性和应用相关的问题，需要首先克服这些问题，才能进一步扩大其应用。
