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Rheological Modeling of Polymer/layered silicate Nanocomposites
Appl. Rheol. 21:2 (2011) 25434 (11 pages) ►
This work takes a phenomenological approach to modeling the rheology of polymer/clay nanocomposites in (shear rate) γ ≤ 1 / s based on experimental observations . The total stress was divided to three contributions: Matrix stress, σM, inter-particle (matrix/particle) stress, σP, and hydrodynamic stress σH. Based on the superposition of complex viscosities, η*, plotted against strain rate amplitude, γ0ω, at different nonlinear strain amplitudes, a modified Bingham-type constitutive equation proposed by Doiraswamy et. al  was used to model σM+σP while σH was modeled by using constitutive equation proposed by Lipscomb et. al  for ellipsoidal particles. The comparison between experimental and modeling results showed that steady hydrodynamic stress in simple shear flows scales with complex viscosities in oscillatory experiments when compared at γ = γ0ω. On the basis of this observation, the network-like behavior of the polymer nanocomposite was attributed to retarded chain dynamics as a result of polymer/clay interactions. In order to take into account the thixotropic behavior of network structure, the constitutive equation proposed by Coussot  was employed for modeling σM+σP. Both Coussot and Doraiswamy equations gave a reasonable quantitative prediction of transient stress in simple shear flow up to shear rates as high as γ = 0.1 / s.► Cite this publication as follows:
Nazockdast E, Nazockdast H: Rheological Modeling of Polymer/layered silicate Nanocomposites, Appl. Rheol. 21 (2011) 25434.
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