Temperature-Triggered/Switchable Thermal Conductivity of Epoxy Resins

Matthias Sebastian Windberger, Evgenia Dimitriou, Sarah Rendl, Karin Wewerka, Frank Wiesbrock*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

The pronouncedly low thermal conductivity of polymers in the range of 0.1–0.2 W m−1 K−1 is a limiting factor for their application as an insulating layer in microelectronics that exhibit continuously higher power-to-volume ratios. Two strategies can be applied to increase the thermal conductivity of polymers; that is, compounding with thermally conductive inorganic materials as well as blending with aromatic units arranged by the principle of π-π stacking. In this study, both strategies were investigated and compared on the example of epoxy-amine resins of bisphenol A diglycidyl ether (BADGE) and 1,2,7,8-diepoxyoctane (DEO), respectively. These two diepoxy compounds were cured with mixtures of the diamines isophorone diamine (IPDA) and o-dianisidine (DAN). The epoxy-amine resins were cured without filler and with 5 wt.-% of SiO2 nanoparticles. Enhanced thermal conductivity in the range of 0.4 W·m−1·K−1 was observed exclusively in DEO-based polymer networks that were cured with DAN (and do not contain SiO2 fillers). This observation is argued to originate from π-π stacking of the aromatic units of DAN enabled by the higher flexibility of the aliphatic carbon chain of DEO compared with that of BADGE. The enhanced thermal conductivity occurs only at temperatures above the glass-transition point and only if no inorganic fillers, which disrupt the π-π stacking of the aromatic groups, are present. In summary, it can be argued that the bisphenol-free epoxy-amine resin with an epoxy compound derivable from natural resources shows favorably higher thermal conductivity in comparison with the petrol-based bisphenol-based epoxy/amine resins
Original languageEnglish
Article number65
Number of pages11
JournalPolymers
Volume13
Issue number1
DOIs
Publication statusPublished - 1 Jan 2021

Keywords

  • Bisphenol-free epoxy resin
  • Crosslinked polymer
  • Epoxy resin
  • Inorganic filler
  • Polymer from natural resources
  • Thermal conductivity
  • π-π stacking

ASJC Scopus subject areas

  • Materials Science(all)
  • Chemistry(all)
  • Polymers and Plastics

Fields of Expertise

  • Advanced Materials Science

Treatment code (Nähere Zuordnung)

  • Basic - Fundamental (Grundlagenforschung)

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