Enhancing the Cold Resistance of Phthalate Plasticizers Through Synergistic Blending

ABSTRACT Phthalate plasticizers are the most commonly used plasticizers for soft PVC, but their composite materials are highly prone to cracking in low‐temperature environments, leading to significant economic losses. Enhancing the cold resistance of plasticizers may be key to solving this issue. Therefore, this study employs dioctyl phthalate (DOP) as the primary plasticizer and synergistically blends it with the synthesized cold‐resistant plasticizers dioctyl adipate (DOA) and dioctyl sebacate (DOS). Experimental results demonstrate that the addition of DOA and DOS significantly improves the low‐temperature toughness of PVC/DOP composite films. For instance, at −20°C, the elongation at break of PVC/DOP/DOA and PVC/DOP/DOS increased by 48% and 42%, respectively, compared to PVC/DOP. Similarly, the glass transition temperatures of the compounding film are also higher than those of PVC/DOP. Migration resistance tests indicate that blending DOP with DOA or DOS can slow the migration rate of both DOS and DOA within the resin. Additionally, low‐temperature in situ Raman spectroscopy is employed to investigate structural changes in DOP/PVC films under extreme cold conditions. DOP gradually precipitates from the matrix phase and forms crystalline structures on the film surface under low temperatures. This leads to PVC plasticization failure, resulting in brittle fracture.