竹纤维素的制备及其功能化材料研究进展

Development of bamboo cellulose preparation and its functionalization

我国竹子资源丰富,产量大,但竹产业整体加工水平不高,传统竹产品技术含量低,市场竞争力弱。从竹纤维素利用的角度,综述了竹子纤维素的分离技术,包括预水解技术、蒸煮技术、漂白技术、漂白化学竹浆选择性去除半纤维素升级制备溶解浆技术;溶解技术,包括CS_(2)/NaOH溶剂体系、金属络合物溶剂体系、碱/尿素和碱/硫脲溶剂体系、NMMO/H_(2)O溶剂体系、离子液体溶剂体系、LiCl/DMAc溶剂体系及功能化利用技术方面的研究进展情况。根据竹纤维素具有可再生、可降解、生物相容性好、亲水性强、机械性能和耐热性能优良等特点,重点介绍了当前国内外利用竹纤维素制备高档纺织材料、过滤膜材料、生物医用材料和光电材料等方面的研究进展情况。最后,结合笔者的研究经历,就竹纤维素材料开发利用方面存在的问题及其未来研究重点和方向阐述了自己的观点,以期为探索绿色、低碳、环保的竹资源利用新技术,开发高技术含量和高附加值竹产品提供借鉴,促进我国竹产业结构升级转型和可持续发展。

As one of the natural biomasses, bamboo features a considerable volume of resource in China, especially in Southern China. However, the overall traditional industrial processing of bamboo commonly involves the low technical level, which leads to the weak competitiveness of bamboo in comparison to other biomasses, such as wood. In regarding to the functionalization treatment to promote applications of bamboo, this review summarizes the separation engineering of bamboo cellulose from the natural bamboo raw materials, which are made up of the pre-hydrolysis treatment(removing hemicellulose), kraft cooking technology(removing lignin), bleaching approach(removing the residual lignin and hemicellulose) and the upgrading strategy of paper-grade pulp to the dissolving pulp(i.e., cellulose). Commonly, the prepared bamboo cellulose is dissolved by the specifical solvents for the subsequently functionalization treatment of cellulose. The main solvents include the CS_(2)/NaOH solvent system, metal complex solution system, NaOH/urea or NaOH/thiourea solution system, NMMO/H_(2)O solution system, ionic liquid solution system, and LiCl/DMAc solution system. All solvents involve the sufficient breakage of hydrogen bonding between cellulose molecules and efficient formation of hydrogen bonding between solvent molecules/ions and the cellulose molecules. The research advances in the functional utilization of bamboo celluloses are also discussed in this review. Specifically, based on the application of bamboo cellulose fibers, the review discusses the research and application developments of the separation techniques, dissolving techniques, and the functional applications of bamboo fibers. As recyclable, degradable, bio-compatible, and high hydrophilic resources, the bamboo fibers also have excellent mechanical and heat-resistant properties. In this review, the applications of bamboo fibers are introduced in different domains in the world, namely the high-end textiles, filtration membrane, bio-medical materials, and photoelectric devices. Based on their research experiences, the authors propose the current limitations and future developments of bamboo fiber applications. As a green, low-carbon and environment-friendly resource, the research on the high-tech and value-add bamboo products would promote the upgrade and sustainable developments of bamboo industry in China.