Preparation of functional flexible polyvinyl chloride plastic by incorporating core-shell star copolymer Lignin-PCL

PVC as an important plastic material, has gained widespread application due to its excellent physical properties, good heat and chemical resistance, as well as low cost. By incorporating plasticizers and other plastic additives, rigid PVC can be extended to applications in the flexible PVC field. However, conventional low-molar-mass phthalate plasticizers tend to migrate from the PVC matrix to the external environment during long-term use. This migration not only deteriorates the physical properties of PVC but also poses risks to human health and the environment. Therefore, improving the stability of plasticizers in PVC materials is of great significance.In this study, two structurally different plasticizers were prepared by hydroxyl-initiated ring-opening polymerization of ε-caprolactone. The mechanical properties of PVC plasticized with Lignin-PCL, C 5 H 12 O-PCL, and the conventional plasticizer DOP were compared. The results show that PVC plasticized with Lignin-PCL exhibited improved mechanical properties compared to those plasticized with the conventional plasticizer. Interestingly, the hyperbranched plasticized PVC demonstrated higher modulus, strength, and toughness than its linear counterpart. The resulting plasticized PVC materials exhibited a high modulus of approximately 30 MPa while ensuring an elongation at break exceeding 300%. The migration rates of all Lignin-PCL-PVC samples were below 5%, which is only 0.026 times that of DOP-PVC. Moreover, as both lignin and PCL are degradable and environmentally friendly materials, the degradation performance of the materials was also investigated. The study found that the hyperbranched plasticizer Lignin-PCL could be degraded by more than 80%, which is crucial for the development of environmentally friendly flexible PVC materials.