Abstract：
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 NaIO4 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.
摘要：
二醛纤维素纳米晶体（DCNC）被定义为C2和C3醛纳米纤维素，可用作纳米纤维素衍生化的原料，由于醛基的高活性。在这里，通过氯化胆碱（ChCl）/尿素基深共晶溶剂（DES）对DCNC萃取进行了NaIO4预氧化和同步氧化的比较研究。环状DCNC，平均粒径为118±11nm，收益率为49.25%，醛基含量为6.29mmol/g，结晶度为69%，和棒状DCNC，平均粒径为109±9nm，产率为39.40%,醛基含量为3.14mmol/g，75％的结晶度可以通过优化的DES处理结合预氧化和同步氧化提取，分别。此外,平均粒径，大小分布，涉及DCNC的醛基含量。TEM,FTIR,XRD,TGA结果揭示了微观结构的变化，化学结构,晶体结构，两种DCNC在提取过程中的热稳定性，即使获得的DCNC表现出不同的微观形态，预氧化,在ChCl/尿素基DES处理期间或同步氧化可以被认为是DCNC提取的有效方法。
