超声处理对制备竹浆微纤化纤维素的影响

The Effect of Ultrasonic Time on Preparation of Microfibrillated Cellulose from Bamboo Fibers

关键词:  微纤化纤维素  超声时间  竹浆纤维

Key Words:microfibrillated cellulose  ultrasonic time  bamboo fibers

摘要:以漂白竹浆为原料,采用中性2,2,6,6-四甲基哌啶-氮-氧化物(TEMPO)微波氧化预处理,然后在浆浓0.6%下结合超声波处理将竹浆纤维素分离解纤为微纤化纤维素(MFC)。通过表观分散性观察、透射电子显微镜(TEM)、傅里叶变换红外吸收光谱(FI-TR)和X射线衍射仪(XRD)对不同超声时间所制备的 MFC 的分散特性、形态特征、化学结构、结晶度和晶型结构进行表征分析。结果表明,超声2 h可以得到分散性好、完全透明的MFC,其直径分布均一(5～15 nm),而长度在微米级；超声处理不会改变纤维素的化学结构和晶体类型,但对其结晶度有一定的影响,超声1.5 h其结晶度最高66.97%,超声2.5 h后其结晶度剧烈下降至39.16%。

Abstract:The bleached bamboo fibers were pretreated by neutral TEMPO microwave oxidation process, and then the microfibrillated cellulose (MFC) was prepared by ultrasonic mechanical treatment at 0.6wt% concentration. The dispersion characteristics, morphological features , chemical characteristics, crystallinity and the crystalline type of the as prepared MFC from different ultrasonic time, were analyzed by visual examination, transmission electron microscopy(TEM), Fourier Transform Infrared Spectroscopy (FT-IR) and X Ray Diffraction (XRD). The results showed that MFC was good dispersion and totally transparent after ultrasonic 2 hours. Its length was in microns and its diameter(5~15 nm) had a uniform distribution . Ultrasonication treatment did not alter the chemical structure and the crystalline type of cellulose, but it had some influence on the crystallinity . After ultrasonic treatment 1.5 hours, the crystallinity reached the highest 66.97%, while the crystallinity dropped to 39.16% after ultrasonic 2.5 hours.