The thermal stability of cellulose nanofibrils (CNFs) can be improved by converting cellulose crystalline structure to cellulose II using an alkaline treatment method. The conventional method requires around 20 wt.% NaOH solutions and causes the cellulose interdigitation and aggregation, making CNFs production difficult. The objective of this study is to develop a new pretreatment method using a low-concentration alkaline solution to produce well-dispersed CNFs with improved thermal stability. CNFs with 90 nm diameter were successfully prepared by treating cellulose powder with 2 wt.% NaOH solution below 0 °C, followed by homogenization through a French pressure cell press. The CNFs had relatively high thermal stability with the mean onset and maximum thermal decomposition temperature of 305 °C and 343 °C, respectively, compared with the CNFs prepared without the NaOH pretreatment (283 °C and 310 °C). The increased thermal stability can create new opportunities for the development of CNF-based bio-composites and electronics.

中文翻译：

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使用低浓度碱预处理提高了纤维素纳米原纤维的热稳定性

可以通过使用碱性处理方法将纤维素的晶体结构转变为纤维素II来提高纤维素纳米原纤维（CNF）的热稳定性。常规方法需要约20 wt。％的NaOH溶液，并引起纤维素相互指配和聚集，从而使CNF的生产变得困难。这项研究的目的是开发一种使用低浓度碱性溶液的新预处理方法，以生产具有良好热稳定性的分散良好的CNF。通过在0°C以下用2 wt。％的NaOH溶液处理纤维素粉末，然后通过法国压力室压力机进行均质化，成功制备了直径为90 nm的CNF。CNF具有相对较高的热稳定性，平均起始温度和最高热分解温度分别为305°C和343°C，与未经NaOH预处理（283°C和310°C）制备的CNF相比。增加的热稳定性可以为基于CNF的生物复合材料和电子产品的开发创造新的机会。