A molecular dynamics study on the miscibility and morphology of polyester blends used in coil coatings

Computational simulations can be used to save on both time and costs, complementing experimental work and providing further guidance. Blends of immiscible polymers induce phase segregation, and in some cases can produce useful multicoat systems. This work uses a range of molecular dynamics simulations methods, including an extended Flory Huggins Interaction Parameter (χ) approach to initially probe the interactions and miscibility between ester monomers commonly used in coil coatings. The work indicates that blends with similar backbone structures or “like with like” show increased miscibility and those with different structures lead to a larger χ value and immiscibility. Further to this, polyester blends with different backbone structures have been coarse grained with MARTINI beads and simulations of 10 μs have been run to identify the morphology of the blends at the mesoscopic level. Finally, simulations of the melamine crosslinker commonly used in polyester formulations are consistent with the previously seen formation of agglomerates at higher melamine content.