Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Effect of Nanoparticle Shape on Polymer-Nanocomposite Rheology and
  Tensile Strength   Nanoparticles can influence the properties of polymer materials by a variety
of mechanisms. With fullerene, carbon nanotube, and clay or graphene sheet
nanocomposites in mind, we investigate how particle shape influences the melt
shear viscosity $\eta$ and the tensile strength $\tau$, which we determine via
molecular dynamics simulations. Our simulations of compact (icosahedral), tube
or rod-like, and sheet-like model nanoparticles indicate an order of magnitude
increase in the viscosity $\eta$ relative to the pure melt. This finding
evidently can not be explained by continuum hydrodynamics and we provide
evidence that the $\eta$ increase in our model nanocomposites has its origin in
chain bridging between the nanoparticles. We find that this increase is the
largest for the rod-like nanoparticles and least for the sheet-like
nanoparticles. Curiously, the enhancements of $\eta$ and $\tau$ exhibit {\it
opposite trends} with increasing chain length $N$ and with particle shape
anisotropy. Evidently, the concept of bridging chains alone cannot account for
the increase in $\tau$ and we suggest that the deformability or flexibility of
the sheet nanoparticles contributes to nanocomposite strength and toughness by
reducing the relative value of the Poisson ratio of the composite. Our
simulations point to a substantial contribution of nanoparticle shape to both
mechanical and processing properties of polymer nanocomposites.

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The categories of this paper are: gr-qc
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The categories of this paper are: nucl-ex
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The categories of this paper are: chao-dyn
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The categories of this paper are: q-bio
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The categories of this paper are: physics
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The categories of this paper are: hep-lat
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The categories of this paper are: acc-phys
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The categories of this paper are: supr-con
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The categories of this paper are: quant-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: alg-geom
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The categories of this paper are: astro-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: q-alg
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The categories of this paper are: comp-gas
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The categories of this paper are: funct-an