细菌纤维素的分散及表征

Dispersion and Characterization of Bacterial Cellulose

探究了细菌纤维素的聚集态结构,研究不同疏解转数和超声振幅以及超声时间对细菌纤维素分散效果的影响,分别用不同的方法对分散效果进行表征。结果表明,细菌纤维素为纤维素I结构,结晶度为73.38%;疏解处理能使细菌纤维素出现分丝现象,当疏解转数超过25000r时,BC颗粒基本被完全分散成絮状,抽滤得到的BC膜无颗粒痕迹,Zeta电位和浊度分别稳定在-56mV和24.5NTU左右;超声后的细菌纤维素会产生纤维碎片,在振幅60%的条件下超声20min时能达到较好的分散效果,细菌纤维素悬浮液细腻连续,抽滤得到的膜的匀度较好。分散度沉降实验表明,超声处理能明显改善悬浮液的稳定性,分散度可以达到94%左右。

The aggregation structure of bacterial cellulose was explored, and the effects of different blender rotations, ultrasonic amplitudes and time on the dispersion of bacterial cellulose were investigated in this study. Different methods were used to characterization the dispersion effect. The results showed that bacterial cellulose was cellulose I structure with crystallinity of 73. 38%. Bacterial cellulose can be separated into fibrils by blender. When the rotation exceeded 25 000 r, BC particles were basically dispersed into flocs, and there was no particle traces on the BC membranes, the Zeta potential and turbidity were stable at - 56 mV and 24. 5 NTU respectively. Fiber fragments could be produced by ultrasonic treatment. It showed best dispersion effect when the ultrasonic treatment time was 20 minutes with amplitude of 60%, and the bacterial cellulose suspension was delicate and continuous, the uniformity of the membrane was good. Settlement experiments showed that ultrasonic treatment can significantly improve the stability of suspension, and the dispersion could reach 94%.