Cross-Linking of Epoxy Resin by the Monte Carlo method using activation energy

The crosslinking reaction of epoxy resin was evaluated using a Monte Carlo method based on activation energy for reaction determination. The main agent DGEBA and curing agent 44DDS were used, and crosslinked structures were created using Full-Atomistic Molecular Dynamics (FAMD) calculations with VSOP. Tensile calculations on the post-reaction structures were performed to evaluate Young’s modulus, yielding values in good agreement with experiments.

Use Cases Highlights

Creation of crosslinked structures and property evaluation using MD
Based on activation energy evaluation by first-principles calculations
Good agreement with experimental results

Creation of crosslinked structures and property evaluation by MD

An example using SIESTA for DFT calculations to obtain activation energies of reactive sites is shown. Reaction occurrence is judged by the Monte Carlo method based on reaction distance and activation energy.

Reaction process (SIESTA)

Based on activation energy evaluation by first principles

The change in energy with bond length during a reaction, obtained from DFT calculations using SIESTA, is shown. This allows evaluation of activation energy and use as parameters for reactive MD.

Activation energy obtained from DFT (SIESTA) calculations

Modeling of complex three-dimensional structures

An example of reaction calculation using VSOP is shown. As the MD calculation steps proceed, crosslinking reactions occur, and a resin structure model with a three-dimensional network is constructed.

Reaction calculation using VSOP

Reference

[1] Tomonaga Okabe, Tomohiro Takehara, Keisuke Inose, Noriyuki Hirano, Masaaki Nishikawa, Takuya Uehara, "Curing reaction of epoxy resin composed of mixed base resin and curing agent: Experiments and molecular simulation", Polymer 54 (2013) 4660-4668.
[2] V. Sundararaghavan, A. Kumar, International Journal of Plasticity, 47, 111 (2013)

Details of analysis