Extraction and effect of vibration duration in ultrasonic process of cellulose nanocrystal (CNC) from ramie fiber

Biodegradable materials are increasingly being developed to realize environmental sustainability. Cellulose nanocrystal (CNC) was successfully extracted from ramie fiber using an acid hydrolysis process followed by ultrasonic treatment. CNC extraction was carried out by alkalization and bleaching followed by acid hydrolysis using 35% H2SO4 at 45°C for 60 minutes, then ultrasonic treatment with an ultrasonic time of 0, 30, 60, 90 minutes. The resulting CNC ramie fiber was characterized using scanning electron microscope, transmission electron microscope, fourier-transform infrared and x-ray diffraction. The FTIR graph shows the loss of peaks at wave numbers 1735 cm−1, 1373 cm−1 and 1242 cm−1, this shows that acid hydrolysis clear residual acetate groups like hemicellulose and lignin. This result is supported by increasing the crystallinity index of raw ramie fiber 80.7% to 90.45% after acid hydrolysis using H2SO4. The X-ray diffraction pattern on CNC ultrasonic treatment shows that the 60 minutes ultrasonic time has the highest crystallinity index 90.8%. CNC with 60 minutes ultrasonic has a diameter of 5-10nm with a length of 100-250nm and an aspect ratio of 30-25. In the future CNC ramie fiber can be used as a reinforcement in bio / nano composite because of its excellent mechanical properties and biodegradability.