纤维素纳米晶体的改性-水解连续法制备机理及其基质相容性

The cellulose nanocrystal is a kind of novel material that matches our national continuous development schemes. The simplification of preparation and the improvement of compatibility to the matrix are the most important scientific problems. That the modified cellulose is hydrolyzed more feasibly than unmodified ones has been verified in the industrial practice of dyeing and finishing of cotton fabric. Two kinds of phenomenon are found in the subsequent study; the hydrolysis is accelerated with introduction of trichloride trazine into microcrystalline cellulose and the introduced groups are still in the cellulose that is not degraded. The former can be utilized for simplification of preparation and the latter can be utilized for the improvement of the compatibility. The current proposition would be a novel way for the preparation of a modified cellulose nanocrystal through the hydrolysis of the modified cellulose based on triazine, the so-called “continuous way of modification-hydrolysis”. A comprehensive study about the hydrolysis of three kinds of modified cellulose，which are the trichloride triazine modified cellulose, the polystyrene endcapped with trichloride triazine modified cellulose, and the polystyrene polymerized in-situ modified cellulose. The structure and the compatibility to the matrix of the obtained cellulose nanocrystal would be studied comprehensively. The compatibility is quantified with the variation of the properties of polymer –cellulose nanocrystal composite that is prepared with the mixing of the cellulose nanocrystal and several polymers. A quantified model about structure-compatibility would be founded. The result would be utilized on the preparation of cellulose nanocrystal from lignocellulose such as rice straw, in order to found a novel preparation of cellulose nanocrystal based on the continuous modification-hydrolysis.

纤维素纳米晶体是符合我国可再生资源利用战略规划的新材料，其制备过程的简化和基质相容性的改善是该领域的重要科学问题。染整工业实践证明活性染料染色棉织物中的纤维素因改性而易于酸水解。跟踪研究发现两种现象：微晶纤维素中引入少量三氯均三嗪可降低水解难度；改性基团保留在未降解纤维素中。据此，本项目提出先以均三嗪为桥接基团对纤维素进行改性然后水解即“改性-水解连续”法制备改性纤维素纳米晶体。拟系统研究三氯均三嗪、三氯均三嗪封端聚苯乙烯链以及以三氯均三嗪为桥接枝原位生长聚苯乙烯链三种改性纤维素的水解性能、所得纤维素纳米晶体的结构与基质相容性（将纤维素纳米晶体掺入聚合物制备复合材料，以复合材料性能随纤维素纳米晶体含量的变化率来表征）。探讨纤维素纳米晶体的结构-基质相容性之间的关系，构建结构-基质相容性定量模型；将研究结论用于木质纤维素原料的改性与水解，建立纤维素纳米晶体的“改性-水解连续” 制备新方法。

纳米纤维素是最近几年得到全球关注的可再生新材料，其制备和性质是材料领域的研究热点。本项目聚焦于纳米纤维素的改性方法及改性纳米纤维素与不同聚合物基质的相容性机理展开研究，主要进行了三方面的研究工作：1）三嗪改性纳米纤维素的制备、结构与性质。利用均三嗪为桥连接改性链与纳米纤维素，通过改变三嗪衍生物的取代链长研究不同接枝链结构设计对改性纳米纤维素的结构与性质。研究了C2-C12链取代三嗪改性纳米纤维素的结构及其与聚乳酸材料复合的相容性。2）醛基化纳米纤维素的制备、结构与性质。利用高碘酸钠氧化纳米纤维素制得醛基化纳米纤维素，经阳离子化或丙烯酸接枝等改性后与壳聚糖、聚乙烯醇等聚合物的相容性及复合材料的性质；进一步研究所得醛基化纳米纤维素与壳聚糖的交联产物的结构与吸附性能。3）其他方法改性纳米纤维素的制备、结构与性质。采用其他方法改性纳米纤维素的结构、聚合物基质的相容性及复合材料性能，包括苯乙烯原子转移自由基聚合接枝、TEMPO氧化结合阳离子吸附、硅烷及环氧衍生物改性，等，研究改性反应机理、改性纳米纤维素结构与性质、改性纳米纤维素与聚乳酸或聚甲基丙烯酸甲酯等聚合物材料的相容性以及复合材料的性能。本项目的部分研究成果已实现成果转化，项目的纳米纤维素-聚酯复合材料研究成果在江苏盛虹集团有限公司应用，开发了可再生弹性聚酯纤维，用于超细纤维制备、环保纺织面料生产等科技产品推广；项目的阳离子化纳米纤维素交联壳聚糖研究成果在苏州艾美医疗用品有限公司应用，开发了交联壳聚糖水凝胶用于伤口敷料等新产品。今后将把聚乳酸-纳米纤维素复合材料的研究成果用于食品包装。本项目发表论文29篇，其中SCI收录12篇，中文CSCD核心收录论文10篇，会议论文1篇，国际会议分会场口头报告2篇，墙报展示2篇，全国性会议分会场邀请报告1篇，其他英文论文1篇；申请中国发明专利14件，其中授权4件；培养研究生14名，其中毕业博士1名，毕业硕士8名，在读硕士生5名。