毛竹纳米纤维素晶体的制备及特征分析

Isolation and characterization analysis of cellulose nanocrystal from Moso bamboo

以毛竹为原料,首先经过次氯酸钠和氢氧化钠溶液去除竹纤维中的木质素与半纤维素等成分,再通过30%硫酸溶液与超声波处理结合的方法分离出毛竹纳米纤维素晶体。通过扫描电镜(SEM)与透射扫描电镜(TEM)对分离过程中各阶段产物进行形态特征分析,研究结果表明,纳米纤维素晶体的直径在20～85 nm之间。傅里叶红外光谱(FTIR)与X射线衍射(XRD)分析显示,毛竹中的木质素以及半纤维素已基本被移去,α-纤维素以及纳米纤维素晶体的结晶度得到明显的提高。热重分析仪(TGA)分析显示各个分离阶段所得产物的热稳定性均高于原竹纤维,但纳米纤维素晶体的热稳定性较α-纤维素的略低。

Cellulose was extracted from Moso bamboo by carrying out bleaching and alkali treatments with acidified sodi- um chlorite solution and sodium hydrate solution, and then cellulose nanocrystal was isolated from extracted cellulose with the combination of （30%） sulphuric acid and ultrasonic treatment. According to the scanning electron microscopy （SEM） and transmission electron microscopy （ TEM）, the diameter of cellulose nanocrystal was in the range of 20 - 85 nm. The results of fourier transform infrared （FTIR） spectroscopy and X-ray diffraction （XRD） showed that the hemi- cellulose and lignin were removed extensively from the extracted cellulose, and the crystallinity of isolated α-cellulose and cellulose nanocrystal were significantly increased. The thermal stability of bamboo at different purification stages was investigated by thermogravimetric analysis （TGA） and the thermal stability of the bamboo cellulose increased at every purification stages compared to the raw material, however, the cellulose nanocrystal showed a little lower thermal stabili- ty than that of isolated α-cellulose.