Design and Synthesis of Epoxidized Soybean Oil‐Branched Cardanol Ethers as Poly(vinyl chloride) Plasticizers

To overcome the migration of epoxidized soybean oil (ESO) used as a poly(vinyl chloride) (PVC) plasticizer, ESO‐branched cardanol (CD) ethers (ESO‐CDn) are designed and synthesized in this work. The incorporation of the benzene ring and the C15 straight chain of CD provided excellent plasticizing efficiency, and the increase in the molecular weight by branching CD with ESO enhanced the migration resistance of the plasticizer. In this work, two different methods are adopted to prepare PVC/ESO/CD and PVC/ESO‐CDn, namely the one‐step method (dynamic vulcanization of ESO, CD, and PVC) and the two‐step method (synthesis of ESO‐CD and then mixing it with PVC). The first method is convenient, while it is also uncontrollable, leading to an incomplete reaction between ESO and CD. The second method offers a controllable reaction between ESO and CD. The chemical structure of ESO‐CDn is fully characterized. Furthermore, the thermal, mechanical, rheology, and migration resistance properties of PVC/ESO/CD and PVC/ESO‐CDn are compared. The relationship between the molecular structure and plasticizer performance is investigated, and the plasticization mechanism is proposed. The tensile and thermal properties indicate that PVC/35ESO‐CD10 offered a superior anti‐thermal aging performance due to the excellent plasticizing and migration resistance effects of ESO‐CD10.