Plasticization Mechanism and Low‐Temperature Property of PVC with Citrate Octyl‐Decyl Ester Plasticizers

Abstract To address the chlorine balance issue of Salt Lake resources and respond to extreme cold weather, while also developing high‐value‐added applications for polyvinyl chloride (PVC), it is crucial to develop bio‐based cold‐resistant plasticizers. In this study, citric acid was used as a raw material to investigate the effect of molar ratios of octanol and decanol on the structure of citrate octyl‐decyl ester, the amorphization, and the initial stability of PVC. The introduction of these differently structured citrate ester plasticizers facilitates the amorphization of PVC chains and improves the initial stability of PVC. At a molar ratio of 1:2 for octanol and decanol (TO 1 D 2 C), the plasticized PVC with an asymmetric structure demonstrates outstanding mechanical properties and exhibits superior low‐temperature flexibility, achieving a glass transition temperature ( T g ) of −33.5 °C. This is likely due to the longer side chains and higher degree of branching in TO 1 D 2 C, which effectively increased the free volume of PVC, reducing intermolecular interactions at binding sites and thereby enhancing its low‐temperature plasticization effect. MD simulation results indicate that at low temperatures, the tensile stress of the plasticized PVC systems increases. This research broadens the application scope of PVC and provides significant guidance for the development of cold‐resistant PVC.