Bio-Based and Biodegradable PVC Plasticizer Synthesized from CO2 and Castor Oil with Superior Migration Resistance

Poly(vinyl chloride) (PVC), a versatile plastic, requires substantial amounts of plasticizers to enhance its processability and flexibility. However, most commercial plasticizers are low-molecular-weight petrochemical derivatives that suffer from poor migration resistance and raise environmental and health concerns due to their tendency to leach. To address these issues, this study developed a series of bio-based castor oil-polycarbonate (COPPC) plasticizers from renewable feedstocks, including castor oil, carbon dioxide, and epoxides. The results indicate that the synthesized COPPC plasticizer with a molecular weight of 2.7 kg/mol delivers optimal performance. At a loading of 30 phr, it imparts excellent mechanical properties to PVC, with a tensile strength of 29.4 MPa and an elongation at break of 216.8%. Meanwhile, the plasticized PVC films exhibit high optical transparency and outstanding migration resistance in both polar and nonpolar solvents. The mass loss ranged from a minimal 0.54% in deionized water to 0.76% in acetic acid solution, demonstrating exceptional stability. This work presents a promising, migration-resistant, and sustainable alternative to conventional phthalate plasticizers.