Effects of molecular design parameters on plasticizer performance in poly(vinyl chloride): A comprehensive molecular simulation study

Abstract

Plasticizers for poly(vinyl chloride) (PVC), including ortho- and tere-phthalates, trimellitates, citrates, and various aliphatic dicarboxylates, are systematically studied with all-atom molecular simulation. Effects of plasticizer molecular structure on its performance, as measured by performance metrics including its thermodynamic compatibility with PVC, effectiveness of reducing the material’s Young’s modulus, and migration rate in the PVC matrix, are evaluated in the framework of seven molecular design parameters. Previous experimental findings on the plasticizer structure-performance relationship are also reviewed. Comparison with experiments establishes the reliability of our simulation predictions. The study aims to provide a comprehensive set of guidelines for the selection and design of high-performance plasticizers at the molecular level. Molecular mechanisms for how each design parameter influences plasticizer performance metrics are also discussed. Moreover, we report a nontrivial dependence of plasticizer migration rate on temperature, which reconciles seemingly conflicting experimental reports on the migration tendency of different plasticizers.