Fabrication and characterization of biocomposite films based on chitosan/starch for food packaging exploits

The present study was aimed to investigate the physicomechanical properties of biodegradable ternary films based on chitosan (CH) and starch (ST) at different ratios (100ST/0CH, 75ST/25CH, 50ST/50CH, 25ST/75CH and 0ST/100CH) via a simple casting method.The results showed that adding different ratios of chitosan (25-75%) to the control film (100ST:0CH)significantly reduced the moisture content, and elongation at break (EAB) and water vapor permeability (WVP) of the films, as the 75ST:25CH ratio has the lowest values; also, the solubility, tensile strength, contact angle and whiteness index of the films showed a significant increase compared to the control (p <0.05). FT-IR spectra of different films showed interactions through hydrogen bonding between the hydroxyl moieties of ST and amino moieties of CH in the blends, which enhanced the compatibility between the two polymers. On the other hand, the indicators related to the DSC test indicated that the thermal stability of composite films reduced after the addition of ST. SEM microstructural observations clearly demonstrated a re-organization of the surface of the two-phase films due to the presence of ST.The obtained results suggested the effectiveness of blending approach in improving the compatibility of polymers and overall functionality of films.