Plasticizing Effect of Camellia oleifera Seed-Oil-Based Plasticizer on PVC Material Modification

In this study, as the plasticizer, Camellia oleifera seed-oil-based cyclohexyl ester (COSOCE) was prepared by the reaction of cyclohexene oxide and refined C. oleifera seed oil (RCOSO) obtained by acidification hydrolysis after saponification. In addition, the structure of the target product was confirmed by Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and Raman spectroscopy. COSOCE was used as plasticizer-modified polyvinyl chloride (PVC) membranes. The structure of the COSOCE-modified PVC membranes were characterized by Raman spectroscopy and scanning electron microscopy (SEM). The properties of the COSOCE-modified PVC membrane were characterized by contact angle measurements, universal testing machine, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The results revealed that (1) The COSOCE-modified PVC membranes exhibit a good microscopic morphology. Combined with energy-dispersive X-ray spectroscopy (EDS) and contact angle measurement results, the COSOCE-modified PVC membranes are confirmed to be a hydrophilic material. (2) The modified PVC membrane with 60% COSOCE exhibited the best mechanical properties. The tensile strength reached 23.56 ± 2.94 MPa. (3) COSOCE-modified PVC material exhibited better thermal stability, with a loss rate of less than 75% at the end of the first decomposition stage. Compared with that of the dioctyl-phthalate (DOP)-modified PVC membrane, the initial decomposition temperature of PVC was increased by 1.17°C–8.17°C, and the residual rate was increased by 0.67%–5.75%. The carbon–carbon double bond in the COSOCE molecular structure can remove the free radicals generated during the degradation of PVC material and slow down the decomposition rate of PVC. In addition, the double bond can be cross-linked partially with the PVC molecular chain containing the conjugated polyene structure, thereby increasing the movement resistance of the PVC molecular chain segment. Hence, COSOCE can replace DOP as a PVC plasticizer.