酸处理方式对纤维素Ⅰ晶型向Ⅱ晶型转化的影响文献综述

 2022-07-26 02:07

文献综述

酸处理对纤维素Ⅰ晶型向Ⅱ晶型转化的影响

摘要:

纤维素是自然界中分布最广、含量最多的一种多糖,常温下既不溶于水又不溶于一般的有机物,广泛应用于食品、化工、造纸等领域。利用化学及机械处理可从纤维素中制备纳米纤维素,纳米纤维素直径小于100nm。纳米纤维素具有高结晶度、高亲水性、良好的机械性能等优越性能,具有良好的发展前景。在纳米纤维素的不同晶型中,II晶型纳米纤维素的性能最好。首先,用苯醇混合液对木粉进行抽提,去除部分杂质。其次用冰醋酸与次氯酸钠进行酸处理,去除木粉中的木质素;用氢氧化钠进行碱处理,实现纤维素的晶型由纤维素I型向II型的转化。最后通过超细研磨机或超声的方式得到纳米级别的纤维素II型纳米纤维素。本课题主要研究酸处理方式对纤维素的结晶结构变化的影响,通过控制晶型转化的时间点,用X射线衍射仪测试纤维素晶型转化效果。

关键词:II晶型纳米纤维素 、酸处理、转化效果

Abstract:

Cellulose is the most widely distributed and abundant polysaccharide in nature. It is neither soluble in water nor soluble in common organic matter at room temperature, and is widely used in the fields of food, chemical industry and papermaking. Nanofibers can be prepared from cellulose using chemical and mechanical treatments. Nanocellulose has a diameter of less than 100 nm. Nano-cellulose has high crystallinity, high hydrophilicity, good mechanical properties and other superior performance, with good prospects for development. Among the different crystalline forms of nanocellulose, the II crystalline nanocellulose has the best performance. First of all, with benzene alcohol mixture of wood flour was extracted to remove some impurities. Followed by acid treatment with glacial acetic acid and sodium hypochlorite to remove the lignin in the wood flour; alkali treatment with sodium hydroxide to achieve the conversion of the cellulose form from cellulose I to II. Finally by ultrafine grinding machine or ultrasonic way to get nanoscale cellulose type II nanocellulose. This topic mainly studies the influence of acid treatment on the change of the crystalline structure of cellulose. By controlling the time point of the transformation of the crystalline form, the transformation efficiency of the crystalline cellulose is tested by X-ray diffractometer.

Key words: Form II nanocellulose, acid treatment, transformation effect

一、国内外研究情况

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