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Considering Viscoelastic Micromechanics for the Reinforcement of Graphene Polymer Nanocomposites
ACS Macro Letters (2012)
  • Xiguang Li, Texas Tech University
  • Greg B. McKenna, Texas Tech University
Abstract
There has been much recent work investigating the reinforcement
of glassy polymers with nanoparticles, and much excitement has been
generated by some apparent synergies that suggest reinforcements greater
than expected from elastic bound models. Here we show that it is necessary to
consider the thermoviscoelastic response of the polymer matrix in
nanocomposites (PNCs) to fully understand the reinforcement of the filler.
This is especially so because polymer nanocomposites are frequently used at
high fractions of the glass transition temperature Tg, where the time
dependence of the polymer is significant. Therefore it is a conceptual error to
examine the modulus behavior of PNCs via only elastic micromechanics.
When the glass transition temperature increases due to the interactions between reinforcement and polymer, it is more reasonable to use a viscoelastic micromechanics approach to estimate the bounds on modulus behavior of PNCs. Here we use new results for grapheme oxide reinforced poly(ethyl methacrylate) (PEMA) and literature results for reinforced poly(methyl methacrylate) (PMMA) and show that the ultralow loading of graphene oxide raises the Tg of PEMA and PMMA significantly and leads to a large shift of the frequency−temperature properties of the polymer matrix. Our thermoviscoelastic approach shows that apparent extreme reinforcements can be attributed to the changing Tg of the polymer, and the corrected mechanical reinforcement from graphene oxide is much weaker than previously reported.

Keywords
  • viscoelasticity,
  • graphene
Publication Date
Winter February 23, 2012
Citation Information
Xiguang Li and Greg B. McKenna. "Considering Viscoelastic Micromechanics for the Reinforcement of Graphene Polymer Nanocomposites" ACS Macro Letters (2012)
Available at: http://works.bepress.com/xiguang-luc-li/2/