Synthesis and Performance Evaluation of Isosorbide Diesters for Eco‐Friendly Plasticization of Poly(Vinyl Chloride): Influence of Alkyl Chain Length on Mechanical, Thermal, and Migration Properties

Plasticizers play a critical role in polymer processing by reducing melt viscosity and improving moldability and flexibility. They achieve this by weakening intermolecular forces between polymer chains. However, the use of conventional phthalate‐based plasticizers has raised significant concerns due to their endocrine‐disrupting effects, prompting the need for eco‐friendly, biobased alternatives. Therefore, this study aims to synthesize a series of isosorbide‐based plasticizers with varying alkyl chain lengths and blend them with poly(vinyl chloride) (PVC). The resulting films are fabricated via a solution casting method. A distinct shift in the carbonyl absorption band is observed in the plasticized PVC films, indicating improved molecular interactions and miscibility between PVC and the synthesized plasticizers. As the alkyl chain length increases, the tensile strength and hardness of the films improve, while elongation at break decreases. These changes align with shifts in the glass transition temperature ( T g ). Moreover, compared to epoxidized soybean oil, the isosorbide‐based plasticizers exhibit significantly lower weight loss during thermal aging, demonstrating superior resistance to migration and enhanced thermal stability. These findings provide experimental evidence supporting the potential of isosorbide diesters as sustainable, high‐performance plasticizers for PVC, offering a promising direction for developing safe and effective alternatives to phthalates.