纳米纤维素制备技术及产业化现状

Preparation technology and industrialization status of nanocellulose

近年来,随着人们对于可再生生物质资源转化利用的日益重视,纳米纤维素因其独特的性质而受到广泛关注。纳米纤维素在高性能复合材料、电子产品、催化材料、生物医用材料和能源等领域的潜在应用引起了学术界和工业界的浓厚兴趣。纳米纤维素与有着近100年发展历史的石油化工产品之间的竞争将是大势所趋。林业行业、建筑业、石化行业和制造业之间的密切合作是将绿色纳米纤维素引入大型消费品市场的关键。纳米纤维素的成本和性能非常具有市场竞争力,其两大主要产品为纤维素纳米纤丝(CNF)和纤维素纳米晶体(CNC)。目前,CNF的制备主要是用化学和酶解等方法对纤维素纤维进行预处理,再通过机械解纤法来分离和减小经过预处理的CNF尺寸。CNC则是利用无机酸、有机酸、氧化、酶解、离子液体、低共熔溶剂(DES)或超临界水法对纯化纤维素处理得到的。CNF和CNC未来的市场发展将取决于新型高效溶剂体系的开发(如固体有机酸和DES等),可大量应用纳米纤维素、有效降低总体生产成本的相关产品(如纳米纤维素复合钻井液、纳米纤维素-水泥复合材料和纳米纤维素改性塑料等)的研发,以及纤维素纳米材料的相关国际标准、生理毒性和使用规范的制订,从而帮助相关部门研发和利用纤维素纳米材料。

mDuring the past decade,nanocellulose has attracted a considerable attention because of its unique properties and growing interests in the bioconversion of renewable lignocellulosic biomass. Substantial academic and industrial interests have been directed toward potential applications of nanocellulose for various fields including high performance composites,electronics,catalysis,biomedical materials and energy. Nanocellulose will have to compete with petrochemical products from the industry with nearly a century of development experience. Partnerships among forest products,construction,petrochemical and manufacturing industries are the key to introduce green nanocellulose to a large consumer market with competitive cost and performance for its two main product lines： cellulose nanofiber（ CNF）and cellulose nanocrystal（ CNC）. Currently,the CNF extraction is mainly completed by mechanical fibrillation to separate and reduce the size of the CNFs after pretreating cellulose fibers by using chemicals and enzyme. The CNC extraction is carried out by using mineral acids,organic acids,oxidation,enzyme,ionic liquids,deep eutectic solvents（ DES）,and supercritical water with purified cellulose. Future market expansion for both CNFs and CNCs will hinge on the development of newsolvent systems for pretreating lignocellulosic fibers for more efficient nanocellulose production（ e.g.,DES and solid organic acids）; large volume applications for the related products to help lower overall product costs（ e.g.,drilling fluids,cement composites and modified plastics）,international standards for cellulose nanomaterials to help multiple industrial sectors for developing and using the materials,and more eco-toxicological understanding and regulations for using the nanomaterial in various applications.