Novel environmentally sustainable plasticizers based on ricinoleic acid for polyvinyl chloride: structure and properties

Abstract

Migration of conventional petrochemical plasticizers can negatively affect the performance of plasticized products, human health and the environment and result in the reduction of petroleum resources. Thus, the development of bio-based plasticizers with migration resistance is very critical. In this study, two novel bio-based plasticizers with different structures derived from ricinoleic acid, i.e., epoxy acetylated benzyl ricinoleate (EABR) and epoxy acetyl terephthalate ricinoleate (EATPR), with good plasticizing effect and migration resistance were synthesized and characterized. The structure of EABR and EATPR was confirmed using FTIR and ¹H NMR spectroscopies. The mechanical, thermal, and migration properties of the PVC samples plasticized with EABR and EATPR were extensively investigated, and the commercial plasticizer dioctyl terephthalate (DOTP) was used for comparison. The plasticized PVC samples with EABR and EATPR showed similar impact strength, elongation at break, and glass transition temperature (T_g) to DOTP-plasticized samples, indicating a good plasticizing effect on PVC. Furthermore, EABR and EATPR demonstrated superior performance in migration and volatility tests compared to DOTP. Besides, the plasticizing properties of the plasticized PVC were very sensitive to the structure of the plasticizer; EATPR, with a symmetric structure, showed better plasticization and plasticizing efficiency than EABR, with an asymmetric structure. In conclusion, the two bio-based plasticizers derived from ricinoleic acid showed attractive potential as alternatives to phthalate plasticizers, especially EATPR, with a larger symmetric molecular structure and higher aliphatic content.