植物纤维纳米化拆解分离与高值利用

 为进一步阐述机械剪切对植物纤维纳米化拆解分离的作用机制，采用超微细磨-微射流纳米均质化联合的方法制备纤维素纳米纤丝，对其微观形貌、晶体结构、分子聚合度等特性进行综合表征，并探讨了其新型功能材料的主要性能与应用前景。结果表明，微射流纳米均质化特有的剪切方式能拆解分离超微细磨产生的大径级“顽固”微纤丝束（团），提高纤维整体性能。纤维素纳米纤丝直径8~40 nm，长约数微米，在溶液中高度网状交联；保持原料纤维的晶型，结晶度降至44%，分子聚合度降低32%。其自组装薄膜力学性能好、透光性强，是新型集成电路、显示器材、光学材料的良好基材。纤维经过功能化修饰后，获得的新型功能材料质轻多孔、绿色环保、性能可裁剪设计，在污水（空气）净化处理、高效催化、智能控制等领域具有巨大的应用潜力。

Mechanical Defibrillation and Applications of Cellulose Nanofibril from Wood Fiber

To better understand how plant fibers mechanically defibrillate into cellulose nanofibrils, the wood pulp fiber suspension was processed by refining in combination with intense microfluidization. Cellulose nanofibril properties, including the micro-structure, crystallinity, and degree of polymerization were characterized. Several novel composite materials based on the resulting cellulose nanofibril were prepared and their potential applications were examined. The results showed that intense microfluidization further liberated microfibril bundles (aggregations) created during refining, improving the integral properties of resultant nanofibrils. Nanofibril diameters ranged from 8 to 40 nm while lengths varied over several micrometers, and they exhibited a highly tangling network. Although the original crystal structure was preserved, nanofibril crystallinity decreased to 44%, and the degree of polymerization was reduced by 32% compared to that of pulp fiber. Due to excellent mechanical properties and high light transmittance, free-standing cellulose nanofibril films are considered as promising substrates for flexible integral circuit, LED, and optical materials. Multifunctioned cellulose nanofibril aerogels are highly porous and environmentally friendly, which can be optionally tailored for use of water purification, air filtration, intelligent control and as efficient catalysts.