Sustainable synthesis of epoxidized waste cooking oil and its application as a plasticizer for polyvinyl chloride films

For the past decade, environmentally friendly features have been one of the most desired characteristics of most of the arising technologies. The search for materials from renewable sources and the development of novel nonhazardous processes for their production is currently of the utmost relevance. However, significant improvements on the current technologies towards greener less energy-demanding processes are as important as the search for new ones, and sometimes improvements are more easily achievable and more readily applicable. In this work, the feasibility of using waste cooking oil as a feedstock for the production of epoxidized vegetable oil resins in a process devoid of catalyst has been demonstrated. The epoxidation process was carried out using citric acid as the only acidic component, generating no solid residues and a liquid residue less toxic than the one from the conventional processes. The produced epoxidized waste vegetable oil was successfully applied as a primary plasticizer in poly(vinyl chloride) (PVC) films. The produced films showed mechanical and thermal properties matching those of commercial stretch PVC films.