预水解协同低共熔溶剂制备芦苇纤维素纳米纤丝的研究

Study on Preparation of Reed CNF by DES Cooperating Pre-hydrolysis

采用预水解协同低共熔溶剂法(F-DES)制备芦苇纤维素纳米纤丝(CNF),通过对预水解芦苇得率、化学组分等的分析,探讨较佳预水解工艺,采用红外光谱、扫描电子显微镜、粒径分析、X射线衍射仪分析和热重分析等对预水解处理的芦苇以及芦苇CNF进行了表征。研究结果表明,芦苇预水解的较佳条件为:液比1∶6,预水解温度165℃,保温时间50 min。预水解芦苇得率为80.31%,α-纤维素含量为49.62%,预水解处理芦苇纤维素晶型结构未发生变化,保持纤维素Ⅰ型结构。F-DES体系处理预水解芦苇制备CNF的较优工艺条件为:FeCl_(3)·6H_(2)O用量为0.2 mmol/g DES,草酸二水合物/氯化胆碱(Oxd/ChCl)质量比为4∶1,反应时间6 h,温度80℃。制备的CNF粒径为200~800 nm,总体呈现均匀的纳米纤丝状,优化条件下制备的CNF中有90%的粒径分布在300~400 nm之间。

Reed cellulose nanofibril(CNF)was prepared by using deep eutectic solvent(F-DES)combined with pre-hydrolysis.The optimum pre-hydrolysis technology was determined by analyzing the yield,extractive,and chemical components of pre-hydrolyzed reed.The prehydrolyzed reed and reed CNF were characterized by infrared spectrum,scanning electron microscope,particle size analysis,X-Ray diffraction,and thermogravimetric analysis.The results showed that the optimal conditions for pre-hydrolyzing reed were as follows:liquid ratio of 1∶6,pre-hydrolyzing temperature 165℃,and insulation time 50 min.The yield of pre-hydrolyzed reed was 80.31% and α-cellulose content was 49.62%.The crystal structure of reed cellulose did not change after pre-hydrolysis treatment,i.e.,the typeⅠstructure was maintained.The feasible process conditions for preparing CNF from pre-hydrolyzed reed treated by F-DES system were as follows:FeCl_(3)·6H_(2)O dosage of 0.2 mmol/g DES,mass ratio of Oxd/ChCl 4∶1,reaction time 6 h,and temperature 80℃.The as-prepared CNF had homogeneous morphology and particle size ranging from 200 to 800 nm,with 90% of them distributed between 300 and 400 nm.