Highly transparent chitin nanofiber/gelatin nanocomposite with enhanced mechanical properties

Chitin and gelatin are biodegradable and biocompatible polymers which have gained much attention applied as bio-based materials. In this study, Chitin nanofiber (ChNF)/gelatin nanocomposite was synthesized by immersion method followed with drying at room temperature. The ChNF content in the ChNF/gelatin was controlled in a broad range by changing the concentration of gelatin solutions from 2, 5 to 10% during the immersion processes. The prepared ChNF/gelatin showed uniformly nanofiber network structures which embedded inside the gelatin matrix. The UV measurement indicated that the transmittance of ChNF was increased to as high as 88.7% from 65% at 600 nm, regardless of nanofiber content. Young's modulus of the 50.2%-ChNF/gelatin (with the ChNF content of 50.2%) was around 5192 MPa, which was almost two times higher than that of the pure gelatin. This mechanical improvement was attributed to the reinforcing effect from ChNF nano-networks as well as the formation of hydrogen bondings between gelatin and chitin moleculars. Therefore, with the highly transparent and improved mechanical properties, the prepared ChNF/gelatin nanocomposite films may offer promising and broad prospects in the field of food packaging and bio-medical industrials.