Center for Composite Materials - University of Delaware

Research Summary

Molecular Simulations of Cross-Linked Epoxy

Authors: S. C. Chowdhury, B. Z. Haque, J. W. Gillespie Jr.

Introduction

• Epoxy is a thermosetting polymer that has a wide array of uses in the highperformance
composites industry
• Cured cross-linked epoxy serves as matrix that transfer load to the fibers in composites
• Physical properties of the matrix affect the properties of the entire composite

Objectives and Methods

• Characterize the effects of cross-linker on the structure and thermomechanical
properties of the epoxy
• Construct nano-scale model of the epoxy matrix systems and subject them to various sorts of thermo-mechanical loading
• LAMMPS is used for Molecular Dynamics (MD) simulations
• Atomic interactions are modeled with ReaxFF and AMBER force fields
• VMD is used for model visualization

Model Development

EPOXY MODEL DEVELOPMENT
• Molecules considered are Epon 828 and Jeffamine
- Epon 828 with n = 0.13 is considered for all models, Jeffamine n-value varied by model
- Stoichiometric ratio of Epon to Jeffamine is 2:1 for all models
• Stoichiometric ratio of Epon and Jeffamine equilibrated at 700 K with NPT ensemble
• Cross-linked structure created with AMBER force field and crosslinking curing algorithm
EQUILIBRATION
• Cross-linked model quilibrated with AMBER and ReaxFF force fields to reduce internal stress

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