Utilization of waste cooking oil as a substitute for plasticizer in the production of carrageenan/corn-starch bioplastic through extrusion

In the current investigation, to develop a carrageenan/corn-starch bioplastic production technique suitable for commercial-scale production, an alternative method to the commonly used solvent casting technique was implemented through a hot-melt extrusion process. Moreover, to enhance the water resistance of the bioplastic and reduce production costs, waste cooking oil (WCO) was used as a substitute for glycerol-plasticizer. Various weight ratios of waste cooking oil to glycerol (w/w) were used in the formulations. All the material ingredients were compounded using a double screw extruder at 115°C. Subsequently, the resulting extrudate was then cut into resin pellets, followed by hot compression to produce bioplastic film samples. The film samples underwent testing for mechanical properties, water resistance, biodegradability, chemical structure, and morphology. The overall results exhibited that the addition of WCO increased the tensile properties, water resistance, and accelerated biodegradation. These findings were attributed to the presence of ester groups in the polymer structure, the intrinsic hydrophobic nature of WCO, and the formation of voids within the film structure, as revealed by FTIR and SEM analyses. Based on the findings, the utilization of WCO in carrageenan/corn-starch-based bioplastics production offers potential advantages for commercial applications.