Fabrication and properties of cellulose-nanochitosan biocomposite film using ionic liquid

Chitosan is a widely used biopolymer with very attractive properties. However, to compensate for the deficiencies in the application of this bio-macromolecule, many studies have been performed on the preparation of chitosan blends with various polymers, such as cellulose, which is abundant and unique with a tough bio-structure. Because of the different dissolution conditions of chitosan and cellulose, an acceptable industrial and environmentally friendly process to prepare a monotonous cellulose-chitosan composite film has not been achieved yet. Therefore, as an alternative approach, nanochitosan (Nano-CS) particles were synthesized and blended with a cellulose matrix, which was dissolved using ionic liquid. Atomic force microscope and field emission scanning electron microscope (FESEM) images demonstrated that the most frequent size of Nano-CS particles was in the 10–60 nm range. FESEM nano-graphs evidenced monotonous distribution of Nano-CS particles through the produced nano-biocomposite films. X-ray diffractograms indicated that following the dissolution process of cellulose a less ordered cellulose matrix or one with less crystallite sizes was formed. Meanwhile, following the addition of certain amounts of Nano-CS, the mechanical properties were improved. Also, optical analysis exhibited proper transparency of the biocomposite films (≈80 %) in the range of visible wavelengths (400–700 nm).