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

中文关键词:  纤维素纳米纤丝  芦苇  低共熔溶剂  预水解

Key Words:cellulose nanofibril  reed  deep eutectic solvents  pre-hydrolysis

中文摘要:

      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：FeCl₃·6H₂O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。

Abstract:

      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 pre-hydrolyzed 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 type Ⅰ structure was maintained. The feasible process conditions for preparing CNF from pre-hydrolyzed reed treated by F-DES system were as follows： FeCl₃·6H₂O 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.