Xu Yang, Xu Yongjian, Deng Wenhuan, Chen Hao, Xiong Jianhua
College of Bioresources Chemical & Materials Engineering, Shaanxi University of Science & Technology, Xi'an, Shaanxi 710021, China; National Demonstration Center for Experimental Light Chemistry Engineering Education, Shaanxi Provincial Key Laboratory of Papermaking Technology and Specialty Paper Development, Xi'an, Shaanxi 710021, China.
College of Bioresources Chemical & Materials Engineering, Shaanxi University of Science & Technology, Xi'an, Shaanxi 710021, China; National Demonstration Center for Experimental Light Chemistry Engineering Education, Shaanxi Provincial Key Laboratory of Papermaking Technology and Specialty Paper Development, Xi'an, Shaanxi 710021, China; Guangxi Key Laboratory of Clean Pulp & Papermaking and Pollution Control, School of Light Industry and Food Engineering, Guangxi University, Nanning, Guangxi 530004, China.
Int J Biol Macromol. 2023 Aug 15;246:125604. doi: 10.1016/j.ijbiomac.2023.125604. Epub 2023 Jun 29.
Dialdehyde cellulose nanocrystals (DCNC) are defined as C2 and C3 aldehyde nanocellulose, which can be used as raw materials for nanocellulose derivatization, owing to the high activity of aldehyde groups. Herein, a comparative study in NaIO pre-oxidation and synchronous oxidation is investigated for DCNC extraction via choline chloride (ChCl)/urea-based deep eutectic solvent (DES). Ring-liked DCNC with an average particle size of 118 ± 11 nm, a yield of 49.25 %, an aldehyde group content of 6.29 mmol/g, a crystallinity of 69 %, and rod-liked DCNC with an average particle size of 109 ± 9 nm, a yield of 39.40 %, an aldehyde group content of 3.14 mmol/g, a crystallinity of 75 % can be extracted via optimized DES treatment combined with pre-oxidation and synchronous oxidation, respectively. In addition, the average particle size, size distribution, and aldehyde group content of DCNC were involved. TEM, FTIR, XRD, and TGA results reveal the variation of microstructure, chemical structure, crystalline structure, and thermostability of two kinds of DCNC during extraction even though the obtained DCNC exhibiting different micromorphology, pre-oxidation, or synchronous oxidation during ChCl/urea-based DES treatment can be considered as an efficient approach for DCNC extraction.
二醛纤维素纳米晶体（DCNC）被定义为C2和C3醛基纳米纤维素，由于醛基的高活性，它可作为纳米纤维素衍生化的原料。在此，研究了通过基于氯化胆碱（ChCl）/尿素的低共熔溶剂（DES）对DCNC进行提取时，NaIO预氧化和同步氧化的对比研究。通过优化的DES处理分别结合预氧化和同步氧化，可以提取出平均粒径为118±11nm、产率为49.25%、醛基含量为6.29mmol/g、结晶度为69%的环状DCNC，以及平均粒径为109±9nm、产率为39.40%、醛基含量为3.14mmol/g、结晶度为75%的棒状DCNC。此外，还涉及了DCNC的平均粒径、粒径分布和醛基含量。透射电子显微镜（TEM）、傅里叶变换红外光谱（FTIR）、X射线衍射（XRD）和热重分析（TGA）结果揭示了两种DCNC在提取过程中微观结构、化学结构、晶体结构和热稳定性的变化，尽管在基于ChCl/尿素的DES处理过程中获得的DCNC表现出不同的微观形态、预氧化或同步氧化，但仍可被视为一种有效的DCNC提取方法。
