Synthesis and application of an environmental epoxy plasticizer with phthalate-like structure based on tung oil and cardanol for poly(vinyl chloride)

An epoxidized cardanol tungoleate (ECT) based on tung oil and cardanol was synthesized through esterification and epoxidation. The chemical structure of the compound was verified by Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (H-1-NMR). The plasticizing effects of ECT as the main plasticizer in poly(vinyl chloride) (PVC) was studied and compared with the commercial plasticizer dioctyl phthalate (DOP). The thermal migration stabilities, the thermal degradation process and the mechanical properties of PVC samples and the plasticization mechanism of ECT for PVC were investigated through the use of volatility, extraction, discoloration, and tensile tests as well as thermal gravity analysis (TGA), TGA-FTIR analysis, electronic universal testing machine and dynamic mechanical analysis (DMA). Compared with DOP, the ECT plasticized PVC can exhibits better thermal stability, more excellent tensile strength (17.28 MPa) and higher stretchability (629.41%), which is 1161% higher than DOP (1.37 MPa) plasticized PVC film. In addition, the migration resistance and volatility stability of ECT are much better than DOP. Therefore, this fully bio-based plasticizer based on tung oil and cardanol is a promising alternative plasticizer for PVC and may be an excellent phthalate substitute from the perspective of human health and sustainable development.