硫酸水解辅助高压均质法制备小麦秸秆纳米纤维素

Preparation of Wheat Straw Nanocellulose by Acid Hydrolysis Assisted High Pressure Homogenization

中文关键词:  小麦秸秆  纳米纤维素  纳米纤维素晶须  硫酸水解  高压均质法

Key Words:wheat straw  nanocellulose  nanocellulose whisker  sulfuric acid hydrolysis  high pressure homogenization

中文摘要:

      以小麦秸秆纤维素为原料，通过硫酸水解辅助高压均质的方法，分层制备小麦秸秆纳米纤维素（CNC）；分别采用马尔文纳米粒度分析仪、透射电子显微镜、原子力显微镜、傅里叶变换红外光谱仪、X射线衍射仪和热重分析仪对分层制备的小麦秸秆CNC进行表征分析。结果表明，经硫酸水解预处理、离心收集得到的上层清液纳米纤维素（CNC-SL）为纳米纤维素晶须，与原料相比，其结晶度由48.61%提高至71.87%；硫酸水解预处理、离心收集的残余纤维固体（CNC-S）经8次均质处理制备的纳米纤维素（CNC-SP），其粒径分布在100~200 nm，直径约为15 nm，为高结晶度的短棒状纳米纤维素晶须，晶型为I_β型。与原料相比，CNC-SL和CNC-SP的热稳定性均下降。与硫酸水解法制备CNC相比，硫酸水解辅助高压均质法制备的CNC得率较高；与机械均质化方法相比，此方法所需均质次数明显减少。

Abstract:

      Nanocellulose of wheat straw was prepared in layers by means of acidolysis assisted high pressure homogenization. Subsequently， the layered wheat straw nanocellulose was characterized by Marvin nano-particle analyzer， transmission electron microscope， atomic force microscope， infrared spectrum， X-ray diffractometer and thermal stability analyzer. The nanocellulose prepared from the supernatant was the nanocellulose whisker， and the crystallinity increased from 48.61% of the wheat straw materials to 71.87%. The residual fiber solids of wheat straw after cellulose acidolysis were homogenized for 8 times under the condition of 150 MPa to obtain nanocellulose. The resulted particle size distribution was 100~200 nm， the diameter was about 15 nm， and the same nanocellulose whiskers with high crystallinity （I_β） were obtained. The thermal stability of both nanocellulose wiskers decreased compared with the raw materials. The yield of nanocellulose prepared by this method was higher than that by the method of complete sulfuric acid hydrolysis， and the number of homogenization times was obviously reduced compared with that of complete mechanical homogenization.