TEMPO氧化修饰的天然多糖纳米纤维增强复合材料及其功能化研究进展

Research progress of TEMPO oxidation modified natural polysaccharide nanofiber reinforced composites and their functionality

纤维素和几丁质具有相似的结构,是自然界中储量丰富的两类天然多糖。经2,2,6,6-四甲基哌啶氮氧化物(TEMPO)氧化修饰制备的纤维素和几丁质纳米纤维,不仅具有多糖类物质的良好亲水性、生物可降解性、生物相容性及丰富的官能团(羟基、羧基、乙酰氨基和氨基等)所带来的特定化学性质,而且还具有纳米纤维的纳米尺寸效应、大比表面积、高表面活性、高结晶度和手性液晶相结构等特点,已成为生物质纳米材料领域的研究重点之一。本文对TEMPO氧化修饰制备天然多糖纳米纤维的方法及剥离机制进行了总结,同时重点综述了TEMPO氧化修饰的天然多糖纳米纤维在薄膜、凝胶、导电、医用、电磁屏蔽及环境等复合材料的增强和功能升级等方面的研究进展,强调了纤维素和几丁质纳米纤维的官能团及纳米尺寸在复合材料中的增效机制。最后,对天然多糖纳米纤维的发展方向及其在各领域应用的机遇与挑战进行了展望。

Cellulose and chitin are polysaccharides that abundantly exist in nature and have similar structures.Cellulose and chitin nanofibers prepared by using 2,2,6,6-tetramethylpiperidine-1-oxyl radical(TEMPO)oxidization,not only have good hydrophilicity,biodegradability,biocompatibility and the active chemical properties brought by various functional groups(hydroxyl,carboxyl,acetyl,amino,etc.),but also have the characteristics of large specific surface area,chiral liquid crystal phase,high crystallinity,high transparency and specific nano effect caused by nano size.These natural polysaccharide nanofibers have become one of the research focuses in the field of biomass nanomaterials.In this review,the TEMPO oxidation methods used for the preparation of natural polysaccharide nanofibers,as well as the nanofiber extraction mechanism,were comprehensive summarized.At the same time,the up to now research progress on the as-prepared polysaccharide nanofibers-based composites,such as film,gel,conductive,medical,electromagnetic shielding and environmental materials,with focusing on its mechanical enhancement and function upgradation performance were reviewed.Specific focus is giving to the contributions of the functional groups and nano size of cellulose and chitin nanofibers on the performance improvements of the composites.Finally,the development direction of natural polysaccharide nanofibers and the opportunities and challenges of their applications in various fields are prospected.