(181aq) Performance of Phthalates and Alternative Plasticizers in PVC Via Molecular Simulation: Materials Properties and Migration Tendency

Plasticizers are widely used to improve the properties and processability of certain polymer materials, such as polyvinyl chloride (PVC), in the plastic industry. Phthalates have served as the preferred type of plasticizers to impart flexibility to PVC for decades, as they provide a perfect balance between plasticizer performance and cost. Meanwhile, it is also known that phthalates can cause potential harm to the environment and human health as they have a high tendency of migration and leakage from the host PVC. This has led to increasing governmental regulation which is driving the search for greener and more stable alternatives. We have recently developed a reliable protocol for the prediction of plasticizer compatibility with PVC and the properties of plasticized PVC materials from molecular simulation. Properties such as mixing enthalpy and Young’s modulus are computed by all-atom molecular dynamics simulation and the results are in excellent agreement with available experimental data. The protocol was initially tested on phthalates and is now extended to plasticizers with a wider variety of molecular structures, allowing us to systematically evaluate the effects of molecular design on plasticizer performance. Migration tendency is investigated through the diffusion patterns of these plasticizers, in which clear distinctions are found between different groups of plasticizers such as phthalates, adipates, trimellitates, and citrates. This recent progress provides theoretical guidelines for the molecular design of high-performance migration-resistant plasticizers.