Low-cost and structurally adjustable polyester PVC plasticizer synthesized via alternating copolymerization: Molecular design and plasticizing mechanism

As a widely used polymer additive, polyvinyl chloride (PVC) plasticizers can significantly improve the thermal processing performance and flexibility of PVC. However, commercially available low-molecular-weight plasticizers suffer from poor migration resistance, leading to material failure due to plasticizer migration during long-term usage. In this work, a series of polyesters with long side-chain, poly(OGE-PO-PA) (PGEPE), were successfully synthesized by ring-opening copolymerization of octyl/decyl glycidyl ether (GE), propylene oxide (PO) and phthalic anhydride (PA) for the purpose of plasticizing PVC. The influence of molecular weight and long-branch density on the plasticizing performance was investigated. Results demonstrated that PGEPE-60-3 k, with a long side chain content of 60 % and a molecular weight of 3.0 kg/mol, exhibited most effective plasticizing properties. The plasticized PVC with 30 phr PGEPE-60-3 k plasticizer displayed the optimal mechanical performance with tensile strength of 39.6 MPa and elongation at break of 196 %. Furthermore, it showed high optical transparency and outstanding migration resistance in both polar and non-polar solvents. Mass loss remained minimal, ranging from 0.36 % in 15 % ethanol to 0.93 % in cyclohexane, confirming its excellent stability under various conditions.