Scientific Reports (Jan 2023)

Addressing diffusion behavior and impact in an epoxy–amine cure system using molecular dynamics simulations

  • Sung Hyun Kwon,
  • Haisu Kang,
  • Byeong-Joo Kim,
  • Hyung Ik Lee,
  • Jung Min Lee,
  • Jungchul Kim,
  • Seung Geol Lee

DOI
https://doi.org/10.1038/s41598-022-26835-2
Journal volume & issue
Vol. 13, no. 1
pp. 1 – 10

Abstract

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Abstract To deepen understanding of diffusion-controlled crosslinking, molecular dynamics (MD) simulations are carried out by taking the diffusion image of 3,3′-diamino diphenyl sulfone (3,3′-DDS) and polyethersulfone (PES) with epoxy resin varying temperatures from 393.15 to 473.15 K over crosslinking conversion of 0–85%. The diffusion of PES and 3,3′-DDS into the bulk increased with increasing the temperature as a result of enhanced mobility of the molecules when the difference between the glass-transition temperature (T g ) and the curing temperature. Beyond the onset points of the converged crosslinking conversion ratio of 3,3′-DDS and PES, their diffusion properties are obviously restricted with crosslinking conversion ratio. At low crosslinking conversion ratios (> 10%), the diffusion coefficients of triglycidyl p-aminophenol (TGAP) were 1.1 times higher than those of diglycidyl ether of bisphenol F (DGEBF) because of the lower molecular weight of TGAP. On the other hand, the diffusion coefficients of TGAP decreased when the crosslinking ratio was up to ~ 60% because, compared with DGEBF, it had more functional groups available to react with the curing agent. At higher crosslinking ratios, the diffusion coefficients of both resins converged to zero as a result of their highly crosslinked structures.