Evaluation of mixing efficiency in elaborating of chitosan/cellulose nanocomposite via statistical analyses

Casting films of chitosan (CS)/cellulose nanofibers (CNF) biocomposites containing 0.5-5wt.% of CNF were prepared. Mechanical and physical properties along with scanning electron microscope (SEM) study revealed the best properties for the nanocomposite containing 3wt.% of CNF. Exceeding than this CNF content led to aggregation phenomenon. Then this optimized content nanocomposite was selected in order to investigate the effect of mixing condition on the properties. In the first method the CS and CNF were added simultaneously under ultrasound irradiation. In another method dispersion of CNF was carried out in the solvent separately and then added to the CS solution using ultrasound system. SEM images of the nanocomposites indicated occurrence of aggregation in the simultaneous addition of CS and CNF method. A statistical analysis showed that the best method for effective distribution and dispersion of the nanoparticles within the CS was dispersion of CNF separately in the solvent and addition to the CS solution along with ultrasonic wave's irradiation. The ultrasound induced mixing had a significant effect on the dispersion of the nanoparticles, resulting in significant differences in almost the properties of the nanocomposites.