(670b) Probing Mechanical Behavior of Cross-Linked Polymer Networks Using Atomistic Molecular Dynamics Simulations

Atomistic molecular dynamics simulations were performed to study high strain and high strain rate mechanical and viscoelastic behavior of epoxy-amine (Di-Glycidyl Ether of Bisphenol A and F cured with Jeffamine diamines: D230, D400, D2000) cross-linked polymer networks through the entire stress-strain profile before fracture (elastic regime, plastic regime, yield point) under both glassy and rubbery conditions relevant for energy-dissipating light-weight composite protective materials, adhesives, coatings, paints, membranes, and laminate structures. These systems were built using a novel dendrimer growing algorithm to efficiently cross-link the epoxy and curing agents (amines). In addition to this building method, other polymer network building methods will be compared and discussed in terms of computational efficiency, initial network strain, and chemical and physical realism. Yield and post-yield mechanical behavior were probed to study the effects of amine flexibility on the strength and toughness of these materials. This presentation will discuss the structural, thermal, mechanical, and viscoelastic properties of these materials, which may help guide the chemical design of cross-linked epoxy materials with enhanced toughness and durability.