Development and Characterization of Poly (lactic acid)/Fish Water Soluble Protein Composite Sheets: A Potential Approach for Biodegradable Packaging

Fish water soluble protein was enhanced to thermoplastic prior compounding with Poly (lactic acid) (PLA) using twin screw extruder. A large quantity of water as solvent and oleic acid as plasticizer were incorporated using plasticization (FWSP-ole).Effect of the formulated FWSP-ole concentration, oleic acid and maleic anhydride on the morphology, thermal behavior, mechanical, and permeability of PLA/FWSP-ole composite sheets was studied using scanning electron microscope (SEM) differential scanning microscope (DSC), a universal testing machine and water vapor permeation analyzer, respectively. The results demonstrated that FWSP-ole content resulted in tensile strength increase from 5.33±0.95 MPa (5FWSP-ole) to 11.88±1.82 MPa (10FWSP-ole) but elongation at break was not different. Addition of oleic acid during extrusion process caused extremely increase of elongation at break at 462.96% but a lot of pinhole into composite matrix occurred. On the contrary, maleic anhydride caused reduction size and stretching phase of FWSP resulting in good interfacial adhesion resulting in reduction of pinholes and water vapor permeability. The latest is food contact approved and focused on thermoforming molding application.