Optimization of Ultrasonication Time and Amplitude to Obtain Microbial Nanocellulose with High Degree of Crystallinity

The production of microbial nanocellulose implicates physical and mechanical methods such as the application of ultrafine grinders and ultrasonicators. Nano-sized microbial cellulose must contain high crystallinity to be utilized as a filler in nanocomposite polymers. This research aimed to optimize the processing time and amplitudes of the ultrasonication process to stimulate nano-sized microbial cellulose with high crystallinity. In this analysis the Surface Responses Method was used, that is Central Composite Design (CCD) with two factors, that is processing time (X1 = 30, 60, and 90 minutes) and ultrasonication amplitude (X2 = 70, 80, and 90 %) to the degree of crystallinity. The results indicated the optimum point was obtained at a combination of 60 minutes of processing time and 80% amplitudes with the highest degree of crystallinity of 76.23%. The Fourier Transform Infra-Red spectrum at wavenumbers 3340 cm-1 to 2899 cm-1 showed the characteristics of absorption bands in the form of carboxyl groups and hydroxyl groups, which indicate the existence of cellulose compounds. The scanning electron microscope showed the surface morphology of the ultrafine grinding microbial cellulose fibers was denser.