Tackling the challenge of drying and redispersion of cellulose nanofibrils via membrane-facilitated liquid phase exchange.
Tackling the challenge of drying and redispersion of cellulose nanofibrils via membrane-facilitated liquid phase exchange.
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DOI：
10.1016/j.carbpol.2023.120943
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发表时间：
2023-04
影响因子：
11.2
通讯作者：
A. Onyianta;Guofan Xu;A. Etale;J. Eloi;S. Eichhorn
中科院分区：
文献类型：
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作者：
A. Onyianta;Guofan Xu;A. Etale;J. Eloi;S. Eichhorn
人们普遍认为，为了促进纤维素纳米原纤维（CNF）在产品配方中的应用，必须解决与该材料的干燥和再分散相关的挑战。尽管在这一领域的研究工作有所增加，但这些干预措施仍然涉及使用添加剂或常规干燥技术，这两者都有可能提高最终CNF粉末的成本。在此，我们制备了干燥和可再分散的CNF粉末，具有不同的表面功能，而不使用添加剂，也没有传统的干燥技术。在从水到异丙醇的液相交换之后实现在空气中的快速干燥。表面性质，形态和热稳定性是相同的从未干燥和再分散的形式。在干燥和再分散未改性和有机酸改性的材料后，CNF的流变性质也不受影响。然而，对于具有较高表面电荷和较长原纤维的2，2，6，6-四甲基哌啶1-氧基（克里思）介导的氧化CNF，储能模量不能恢复到从未干燥的状态，因为在再分散时长度可能非选择性减少。然而，该方法提供了一种用于干燥和再分散未改性和表面改性的CNF的有效且低成本的方法。
It is generally acknowledged that to advance the application of cellulose nanofibrils (CNFs) in product formulations, challenges associated with the drying and redispersion of this material must be addressed. Despite increased research efforts in this area, these interventions still involve the use of additives or conventional drying technologies, which both have the capacity to drive up the cost of the final CNF powders. Herein, we prepared dried and redispersible CNF powders with varying surface functionalities without the use of additives nor conventional drying technologies. Rapid drying in air was achieved after liquid phase exchange from water to isopropyl alcohol. The surface properties, morphology and thermal stabilities were the same for the never-dried and redispersed forms. The rheological properties of the CNFs were also unaffected after drying and redispersion of unmodified and organic acid modified materials. However, for 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO)-mediated oxidised CNFs with higher surface charge and longer fibrils, the storage modulus could not be recovered to the never-dried state because of the possible non-selective reduction in length upon redispersion. Nevertheless, this method provides an effective and low-cost process for the drying and redispersion of unmodified and surface modified CNFs.