Nanocrystalline celluloses (NCCs) were successfully extracted from ramie fibers using chemical pretreatments followed by hydrochloric acid hydrolysis. The effects of acid concentration and hydrolysis time on the characteristics of NCCs were investigated in this study. Results showed that the optimal hydrolysis conditions were found to be 6 M hydrochloric acid concentration at 45 °C for 70 min. The obtained NCC had a rod like-shape with an average of 8.07 nm in diameter, 158.51 nm in length, 22.37 in aspect ratio, 89.61% in the crystallinity index, and 5.81 nm in crystallite size. The higher crystallinity and thermal stability were exhibited by NCCs compared to both raw fibers and chemically purified cellulose. The hydrolysis time had a significant effect on crystallinity and thermal stability. The crystallinity index and thermal stability of NCCs were obtained to decrease with increasing hydrolysis time.

The present study investigates the structural, crystallinity index, crystallite size, morphological, and the dimension of Nanocrystalline Cellulose (NCC) extracted from ramie fiber by hydrochloric acid-hydrolysis. NCC was chosen because it has high strength and modulus compared to other natural materials. Ramie fiber was chosen because it has high cellulose content and abundant in Indonesia. The other reason is ramie has a high crystallinity index compared to other natural fibers. The extraction process was carried out into two steps: cellulose purification then followed by hydrochloric acid hydrolysis. The characterizations of extracted NCCs were conducted through Fourier-Transform Infrared spectroscopy (FTIR), X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), and Particle Size Analyzer (PSA). The focus of this research was to study the effect of acid concentration on the characteristics of extracted NCCs. The results show that NCCs could be extracted through hydrolysis using hydrochloric acid. Morphological analysis by TEM shows the formation of rod-like shaped NCCs. Hydrolysis by hydrochloric acid does not affect the chemical compound of cellulose. It was found that during hydrolysis, the higher acid concentration being employed had resulted in smaller dimension of NCCs and decreasing crystallinity index.