Glass transition and structural properties of glycidyloxypropyl-heptaphenyl polyhedral oligomeric silsesquioxane-epoxy nanocomposites: A molecular simulation study

Po Han Lin, Rajesh Khare

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

We have used molecular simulations to study the properties of nanocomposites formed by the chemical incorporation of polyhedral oligomeric silsesquioxane (POSS) particles in the cross-linked epoxy network. The particular POSS molecule chosen-glycidyloxypropyl-heptaphenyl POSS-can form only one bond with the cross-linker and thus was present as a dangling unit in the network. Four epoxy-POSS nanocomposites containing different fractions (up to 30 mass/%) of POSS particles were studied in this work. Well-relaxed atomistic model structures of the nanocomposites were created and then molecular dynamics simulations were used to characterize the density, glass transition temperature (T g), and the coefficient of volume thermal expansion (CVTE) of the systems. In addition to the effect of nanoparticle loading, the effect of nanoparticle chemistry on the nanocomposite properties was also characterized by comparing these results with our previous results (Lin and Khare, Macromolecules 42:4319-4327, 2009) on neat cross-linked epoxy and a nanocomposite containing a POSS nanoparticle that formed eight bonds with the cross-linked network. Our results showed that incorporation of these monofunctional POSS particles into cross-linked epoxy does not cause a measurable change in its density, glass transition temperature, or the CVTE. Furthermore, simulation results were used to characterize the aggregation of POSS particles in the system. The nanofiller particlesctr Power Energy Systems.

Original languageEnglish
Pages (from-to)461-467
Number of pages7
JournalJournal of Thermal Analysis and Calorimetry
Volume102
Issue number2
DOIs
StatePublished - Nov 2010

Keywords

  • Epoxy
  • Glass transition
  • Molecular simulation
  • Nanocomposite
  • Particle aggregation
  • Polyhedral oligomeric silsesquioxane

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