基于酶预处理的纤维素微纤丝制备调控机制及形态、结构和性能研究

There is a huge potential for enzymatic pretreatment technology to regulate and control the energy consumption connected to the mechanical disintegration of the fibers into cellulose microfibril (CMF) and yield, morphology, structure and properties of CMF. In this study, we first prepare fiber samples that refer to different mechanical disintegration energy consumption and different yield, morphology, structure and properties of CMF before and after enzymatic pretreatment. Then, fiber surface properties change due to enzymatic pretreatment would be investigated from study of the change of fibers' dynamic contact angle etc. Cell wall topochemical change due to enzymatic pretreatment would be investigated from study of the change of cell wall components etc. Furthermore, cell wall structure and characteristics change due to enzymatic pretreatment would be investigated from study of the change of cell wall pore structure and mechanical properties etc. Therefore, the mechanisms of enzymatic pretreatment would be exposited. And then, the relationship and regulatory mechanisms of enzymatic pretreatment with mechanical disintegration energy consumption, mechanical disintegration energy consumption with yield, morphology, structure and properties of CMF, and enzymatic pretreatment with yield, morphology, structure and properties of CMF would be studied respectively. Therefore, the action mechanisms of enzymatic pretreatment regulate and control the energy consumption connected to the mechanical disintegration of the fibers into CMF and yield, morphology, structure and properties of CMF can be elucidated and revealed from many angles. This study will provide essential data and fundamental basis for optimization study of enzyme species and enzymatic pretreatment technological conditions, which will produce better results of regulation and control on mechanical disintegration energy consumption and CMF qualities, and practical application of enzymatic pretreatment technology in CMF preparation.

酶预处理在调控纤维素微纤丝(CMF)制备时的机械解离能耗及CMF得率、形态、结构和性能方面具有很大潜力。制备出对应于不同机械解离能耗和不同CMF得率、形态、结构和性能的酶预处理前后的纤维样品，通过研究纤维动态接触角等变化来探讨纤维表面性能变化，通过研究细胞壁化学组分等变化来探讨细胞壁局部化学变化，通过研究细胞壁孔隙结构和力学性能等变化来探讨细胞壁结构和性能变化，以揭示酶预处理机理。进而分别研究酶预处理与机械解离能耗的关系及调控机制，机械解离能耗与CMF得率、形态、结构和性能的关系及调控机制，酶预处理与CMF得率、形态、结构和性能的关系及调控机制。从多角度阐明和揭示酶预处理调节和控制CMF制备时的机械解离能耗及CMF得率、形态、结构和性能的作用机制。为具有较佳机械解离能耗和CMF质量调控效果的酶种类和酶预处理工艺条件的优化研究及酶预处理技术在CMF制备中的实际应用提供基础数据和理论基础。

本研究分别采用复合纤维素酶、内切纤维素酶、外切纤维素酶对植物纤维进行预处理，研究了酶预处理对纤维性能、形态、纤维素聚合度、细胞壁化学组分和结构的影响，揭示了酶预处理机理。研究了不同酶水解程度及不同机械解离能耗与纤维素微纤丝(CMF)形态、结构和性能的关系及调控机制。结果显示，相同均质条件下，随着酶用量的增加，所需能耗逐渐下降。随着均质次数的增加，机械解离能耗增加，微纤丝化程度提高，CMF逐渐分离并变短，直径分布变得更加均匀，但当均质次数达到一定程度后，CMF的形态并不会再发生显著的变化。漂白马尾松纤维经酶预处理和高压均质处理，可以制备出直径分布在20nm-40nm之间的CMF，说明酶预处理有利于获得直径更小、更均匀的CMF。高压均质制备聚合度为350的CMF时，经10 FPU/g纤维素酶预处理的高压均质机械解离能耗比未经酶预处理的节省约64%，这主要是由于纤维素酶水解造成植物纤维细胞壁中纤维素降解，改变纤维的表面形态及内部结构，产生更多的应力弱点，从而极大降低细胞壁机械解离时的能量消耗。对比不同原料制备CMF研究发现，漂白麦草纤维的机械解离能耗比漂白马尾松纤维的低很多，即禾本科的漂白麦草纤维更容易制备CMF。综上所述，通过调节酶水解程度，可以调节机械解离能耗、CMF形态和性能，通过调节机械解离能耗，也可以调节CMF形态和性能。本研究揭示了酶预处理机理，阐明了酶预处理、机械解离能耗和CMF三者之间的关系和调控机制，对酶促CMF的工业化制备技术的研究和开发有重要的、积极的指导意义。.制备出了两种功能化纳米纤维素，初步探索了其在紫外线防晒剂和防伪材料中的应用。研究表明稀土配合物接枝到纳米纤维素可作为一种高效稳定的紫外线防晒剂，以及在柔性OLED中具有潜在的应用价值；此外，用稀土基碳量子点改性纳米纤维素制备出的荧光纳米纸具有三重密码信息。因此，功能化改性的可见-近红外双发射荧光纳米纤维素可用作防伪墨水或进一步构筑高性能、透明防伪纳米纸，在防伪材料领域具有潜在的应用价值。