Birefringence Behaviors of Cellulose Nanocrystals under Varied Concentrations, Ultrasonication Treatments, and Different Solvents

Abstract

Self-assembly of cellulose nanocrystal (NCC) in suspension has unique characteristics under polarize observation which is called as birefringence behaviors. However, the study about these phenomena is lacking especially when the NCC is prepared in dried powder form. Here, we reported the behaviors of commercial NCC obtained from CelluForce NCC, NCV100-NASD90 dispersed in different concentrations (0.1% to 8% weight/weight); ultrasonic times (0 to 45 minutes); solvents (Benzene, N,N-Dimethylacetamide (DMA), Ethanol, Dimethylformamide, Acetone, Acetic acid 1%, and Water) for their birefringence manners. In addition, nanocellulose obtained from TEMPO mediated oxidation and organic acid hydrolysis were also reported. Dried powder NCC showed shear thickening behavior at high concentration and well-dispersed at acetic acid and water solvent indicated the redispersable NCC. While, cellulose NCC, NCV100-NASD90 considerably low dispersion in non-polar solvents. Birefringence appears only when the suspension was in anisotropic state due to stirring. As sonication times increased, the birefringence clearly visible which suggested the defibrillation of aggregated cellulose crystal. The results of this study authenticated that redispersable NCC could be obtained from dried powder cellulose and provided birefringence behavior by managing concentration levels, sonication times and perfect solvents to dilute.