CAS Kay Laboratory of Bio-Based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; Johan Gadolin Process Centre, C/O Laboratory of Wood and Paper Chemistry, Åbo Akademi University, Turku FI-20500, Finland.
Johan Gadolin Process Centre, C/O Laboratory of Wood and Paper Chemistry, Åbo Akademi University, Turku FI-20500, Finland.
Carbohydr Polym. 2015 Nov 20;133:605-12. doi: 10.1016/j.carbpol.2015.07.033. Epub 2015 Jul 15.
Cellulose nanocrystals (CNCs) as a renewable and biodegradable nanomaterial have wide application value. In this work, CNCs were extracted from bleached chemical pulp using two stages of isolation (i.e. formic acid (FA) hydrolysis and 2,2,6,6-tetramethyl-piperidine-1-oxyl (TEMPO) mediated oxidation) under mild conditions. In the first stage, FA was used to remove hemicellulose, swell cellulose fibers, and release CNCs. The FA could be readily recovered and reused. In the second stage, the CNCs isolated by FA were further modified by TEMPO-mediated oxidation to increase the surface charge of CNCs. It was found that the modified CNCs with more ordered crystal structure and higher surface charge had better redispersibility and higher viscosity in aqueous phase. Therefore, the modified CNCs could be more effective when used as rheology modifier in the fields of water based coating, paint, food etc.
纤维素纳米晶体（CNCs）作为一种可再生和可生物降解的纳米材料具有广泛的应用价值。在这项工作中，使用两段式分离（即甲酸（FA）水解和 2,2,6,6-四甲基哌啶-1-氧自由基（TEMPO）介导的氧化）在温和条件下从漂白化学浆中提取 CNCs。在第一阶段，使用 FA 去除半纤维素、溶胀纤维素纤维并释放 CNCs。FA 可以很容易地回收和再利用。在第二阶段，通过 TEMPO 介导的氧化进一步修饰 FA 分离得到的 CNCs，以增加 CNCs 的表面电荷。结果发现，具有更有序晶体结构和更高表面电荷的改性 CNCs 在水相中有更好的再分散性和更高的粘度。因此，改性 CNCs 可用作水基涂料、油漆、食品等领域的流变改性剂，效果更好。
