Polyester polyol polymer materials are utilized in various forms such as in coatings, adhesives, sealants, polyurethane flexible and rigid foams, and in elastomers. These polymers can be synthesized with many different monomer molecules that are either solely hydroxy or carboxylic acid difunctional or multifunctional to give multiple ester bonds and hydroxy ends in the polyester polyol. Incorporation of this polymer for applications commonly involves crosslinking the polyols to make a network structure. To simulate this material, we have made top-down coarse-grained models of the monomers involved using the corresponding states correlation to the SAFT-γ Mie EoS.
1–3 Using this theory, we obtained Mie potential parameters from monomer critical temperatures, acentric factors, and densities at Tr=0.7
4 to use in molecular simulations. Joining the monomer models together appropriately constructs the polymer model. The simulations are designed to model specific experimental polyester polyol resins, matching experimental composition and characterization of molecular weight distribution. Key properties of the polyester polyol resin agree well between simulation and experiment including density, glass transition temperature (Tg) and change in heat capacity across the glass transition. Additional simulations designed to explore the Mie model parameter space led to a fit equation for Tg that predicted the Tg of experimental resin simulations. Our results with polyester polyols suggest that the properties of polymer resins can be estimated with reasonable accuracy from a relatively small amount of experimental data. Crosslinker and solvent molecules are also being fit with Mie models. Further simulations involve heuristic crosslinking of the polyester polyols and characterization of structural and mechanical properties.
References
1. Mejia, A., Herdes, C. & Mueller, E. A. Force Fields for Coarse-Grained Molecular Simulations from a Corresponding States Correlation. Ind. Eng. Chem. Res. 53, 4131–4141 (2014).
2. Lafitte, T. et al. Accurate statistical associating fluid theory for chain molecules formed from Mie segments. J. Chem. Phys. 139, (2013).
3. Lymperiadis, A., Adjiman, C. S., Galindo, A. & Jackson, G. A group contribution method for associating chain molecules based on the statistical associating fluid theory (SAFT-gamma). J. Chem. Phys. 127, 234903 (2007).
4. Design Institute for Physical Properties, S. by Aic. DIPPR Project 801 - Full Version. Design Institute for Physical Property Research/AIChE (Design Institute for Physical Property Research/AIChE, 2005).
