Optimisation of physical and mechanical properties for biodegradable chitosan-nanocellulose nanocomposites

Extracted chitosan powder from crustacean crust has a high capacity for film forming; chitosan films are very resistant against breaking. On the other hand, cellulose nanoparticles have high biodegradability rates and are cheaper than other nanofillers. The aim of current research was to prepare and optimize chitosan-nanocellulose nanocomposites in order to utilize whole capabilities of these common materials. Chitosan powder with a high molecular weight, nanocellulose particles having diameters of 20-50 nm and glycerol were applied for optimisation purposes of nanocomposite properties. Addition of cellulose nanoparticles to chitosan films decreased moisture content, increased (till 30.1%) elongation-at-break and improved a* and b* values for final nanocomposites; decrease of glycerol concentration caused a decrease (till 28.7%) in water solubility and water vapour permeability rate and simoultanously increased (till 3.7 GPa) elastic module of nanocomposite. Nanocomposites containing 1 gr chitosan, 0.18% nanocellulose and 30% glycerol led to the highest desirability (75%). Scanning electron microscopy revealed that high concentrations of chitosan powder and cellulose nanoparticles could construct an intricate structure which justifies improvement of elongation capability after addition of nanoparticles to the chitosan films.