Fabrication and characterization of biocomposite films based on carboxymethyl cellulose/polyvinyl alcohol/fish gelatin for food packaging exploits

The present study was aimed to investigate the physical and mechanical properties of biodegradable ternary films based on carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA) and fish gelatin (FG) at different ratios (50CMC/50PVAG:0FG, 40CMC/40PVA:20FG, 35CMC/35PVA:30FG, 30CMC/30PVA:40FG and 25CMC/25PVA:50FG) via a simple casting method. The results showed that adding different ratios of FG (20- 50%) to the control film (50CMC/50PVAG:0FG) significantly reduced the solubility and tensile strength of the films, as the 25CMC/25PVA:50FG ratio has the lowest values; also, the moisture content, contact angle, whiteness index, water vapor permeability (WVP) and elongation at break (EAB) 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 polar groups of FG and hydroxyl moieties of CMC and PVA in the blends, which enhanced the compatibility between the three polymers. However, differential scanning calorimetry results (DSC) indicated that the thermal stability of composite films reduced after the addition of FG. The obtained results suggested the effectiveness of blending approach in improving the compatibility of polymers and overall functionality of films.