ABSTRACT

Cellulose nanocrystals (CNCs) or cellulose nanofibers (CNFs) with different morphologies, chemical, mechanical and physical properties can be obtained when microcrystalline cellulose is subjected to enzymatic, chemical or mechanical treatment. With the aim of utilizing cellulose nanofibrils (CNFs) from Oryza sativa, we isolated microcrystalline cellulose using the Kraft process, followed by successive fiber fibrillation using mechanical grinding, then (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl (TEMPO) mediated oxidation. Analysis of pulp fibers obtained after each treatment step revealed that fiber properties such as length, crystallinity and crystal size changed when the pulp was subjected to mechanical grinding, ultrasonication and TEMPO mediated oxidation. The degree of crystallinity of the fibers increased while crystal size and fiber length decreased after each treatment. TEMPO mediated oxidation led to a decrease in fiber length and an increase in degree of crystallinity of the fibers as compared to mechanical treatment and ultrasonication. It further introduced carboxyl functional groups (COOH) on the surface of the fibrils, which implies that the nanofibers obtained in this study could be further functionalized. Hence, TEMPO mediated oxidation offers the possibility of further chemical functionalization of cellulose nanofibers isolated from agricultural residues.

摘要

对微晶纤维素进行酶法、化学或机械处理后，可以获得具有不同形态、化学、机械和物理性能的纤维素纳米晶体（CNCs）或纤维素纳米纤维（CNFs）。旨在利用来自Oryza sativa的纤维素纳米纤维 (CNF)，我们使用牛皮纸工艺分离微晶纤维素，然后使用机械研磨连续纤维原纤化，然后是（2,2,6,6-四甲基哌啶-1-基）氧基（TEMPO）介导的氧化。对每个处理步骤后获得的纸浆纤维的分析表明，当纸浆经受机械研磨、超声处理和 TEMPO 介导的氧化时，纤维的长度、结晶度和晶体尺寸等特性发生了变化。每次处理后纤维的结晶度增加，而晶体尺寸和纤维长度降低。与机械处理和超声处理相比，TEMPO 介导的氧化导致纤维长度减少和纤维结晶度增加。它进一步在原纤维表面引入羧基官能团（COOH），这意味着本研究中获得的纳米纤维可以进一步功能化。因此，TEMPO 介导的氧化提供了进一步化学功能化从农业残留物中分离的纤维素纳米纤维的可能性。