DFA-FDE Furan-Based Epoxy Thermoset

This tutorial covers an epoxy-amine cure using furan-derived monomers: FDE, a furfuryl diepoxide, and DFA, a difurfuryl diamine. The cure chemistry is the same step-growth epoxy-amine reaction covered in example 3 — the new content here is:

• Furan heterocycles in the monomers. Both species carry one or two aromatic furan rings, which are an attractive “green” feedstock family for thermoset polymers (furans can be derived from sugars).

• A bisphenol-A-free, fused-heterocycle alternative. FDE plays the structural role DGEBA played in tutorial 3; DFA plays the structural role of PACM. The reactive atoms and atom-mapping scheme on FDE are deliberately identical to those on DGE, so the reactions block reads almost the same.

Historically this example was painful because openbabel’s mol2 writer produced inconsistent atom numbering for fused heterocycles, forcing a PDB-based workflow with manual atom renaming. The SMILES atom-mapping path now in htpolynet ([CH:1], [NH2:1] etc.) sidesteps that entirely — the same self-contained-YAML approach used by the earlier examples works cleanly here too.

Contents:

• Introduction
• Monomers
  • FDE
  • DFA
  • A note on the SMILES
• Reactions
  • Primary-to-secondary amine
  • Secondary-to-tertiary amine
  • Oxirane-formation cap
  • How these expand
• The Configuration File
  • constituents
  • What the expansion produces
• Running the Build
  • Setup
  • Densification, precure, CURE, postcure
  • Final
• Results
  • Try it
  • A note on figures
• Post-build simulations and analyses
  • The postsim configuration
  • Density during annealing and equilibration
  • Glass-transition temperature and Young’s modulus
  • Free volume