Comparing the mechanical response of di‐, tri‐, and tetra‐functional resin epoxies with reactive molecular dynamics

• Published in: Journal of polymer science. Part B, Polymer physics Vol. 56; no. 3; pp. 255 - 264
• Main Authors: Radue, Matthew S., Jensen, Benjamin D., Gowtham, S., Klimek‐McDonald, Danielle R., King, Julia A., Odegard, Gregory M.
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01-02-2018
• Subjects: computer modeling; crosslinking; Deformation; Mechanical analysis; Mechanical properties; Modulus of elasticity; Molecular dynamics; Poisson's ratio; thermosets; Yield point; yielding
• ISSN: 0887-6266; 1099-0488
• DOI: 10.1002/polb.24539

ABSTRACT
The influence of monomer functionality on the mechanical properties of epoxies is studied using molecular dynamics (MD) with the Reax Force Field (ReaxFF). From deformation simulations, the Young's modulus, yield point, and Poisson's ratio are calculated and analyzed. Comparison between the network structures of distinct epoxies is further advanced by the monomeric degree index (MDI). Experimental validation demonstrates the MD results correctly predict the relationship in Young's moduli. Therefore, ReaxFF is confirmed to be a useful tool for studying the mechanical behavior of epoxies. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 255–264
A molecular modeling strategy is developed to predict the elastic modulus and yield strength of three different epoxy systems: di‐, tri‐, and tetra‐functional. This is achieved using a reactive force field (ReaxFF) that simulates the scission of covalent bonds in the epoxy molecular structure. The predicted properties are validated with mechanical testing experiments.