Dynamics of Wormlike Polymers in Solution:  Self-Diffusion and Zero-Shear Viscosity

Abstract Based upon the Doi-Edwards theory, a simple expression has been obtained for zero-shear viscosity in terms of the plateau modulus and the crossover frequency. There are no adjustable parameters in the expression. The model is in very good agreement with the zero-shear viscosity values for linear polybutadienes, the typical discrepancy being ∼5–10%. If the model can be validated for other linear amorphous polymers, it may become possible to estimate the zero-shear viscosity by measuring a single Theological parameter (the crossover frequency).

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Impact of Graphene Oxide on Zero Shear Viscosity, Fatigue Life and Low-Temperature Properties of Asphalt Binder

Materials ◽

10.3390/ma14113073 ◽

2021 ◽

Vol 14 (11) ◽

pp. 3073

Author(s):

Abbas Mukhtar Adnan ◽

Chaofeng Lü ◽

Xue Luo ◽

Jinchang Wang

Keyword(s):

Graphene Oxide ◽

Fatigue Life ◽

Low Temperature ◽

Shear Viscosity ◽

Storage Stability ◽

Asphalt Binder ◽

Asphalt Binders ◽

Test Results ◽

Zero Shear Viscosity ◽

Modified Asphalt

This study has investigated the impact of graphene oxide (GO) in enhancing the performance properties of an asphalt binder. The control asphalt binder (60/70 PEN) was blended with GO in contents of 0%, 0.5%, 1%, 1.5%, 2%, and 2.5%. The permanent deformation behavior of the modified asphalt binders was evaluated based on the zero shear viscosity (ZSV) parameter through a steady shear test approach. Superpave fatigue test and the linear amplitude sweep (LAS) method were used to evaluate the fatigue behavior of the binders. A bending beam rheometer (BBR) test was conducted to evaluate the low-temperature cracking behavior. Furthermore, the storage stability of the binders was investigated using a separation test. The results of the ZSV test showed that GO considerably enhanced the steady shear viscosity and ZSV value, showing a significant contribution of the GO to the deformation resistance; moreover, GO modification changed the asphalt binder’s behavior from Newtonian to shear-thinning flow. A notable improvement in fatigue life was observed with the addition of GO to the binder based on the LAS test results and Superpave fatigue parameter. The BBR test results revealed that compared to the control asphalt, the GO-modified binders showed lower creep stiffness (S) and higher creep rate (m-value), indicating increased cracking resistance at low temperatures. Finally, the GO-modified asphalt binders exhibited good storage stability under high temperatures.

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Comparison of the Effective Radius of Sterically Stabilized Latex Particles Determined by Small-Angle X-ray Scattering and by Zero Shear Viscosity

Langmuir ◽

10.1021/la980356c ◽

1998 ◽

Vol 14 (18) ◽

pp. 5083-5087 ◽

Cited By ~ 31

Author(s):

A. Weiss ◽

N. Dingenouts ◽

M. Ballauff ◽

H. Senff ◽

W. Richtering

Keyword(s):

Shear Viscosity ◽

Small Angle ◽

Effective Radius ◽

Zero Shear Viscosity ◽

Latex Particles ◽

X Ray ◽

X Ray Scattering ◽

Ray Scattering

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Investigation of Microscopic Structure and Ion Dynamics in Liquid Li(Na, K)EutecticCl Systems by Molecular Dynamics Simulation

Applied Sciences ◽

10.3390/app8101874 ◽

2018 ◽

Vol 8 (10) ◽

pp. 1874 ◽

Cited By ~ 1

Author(s):

Jie Wu ◽

Jia Wang ◽

Haiou Ni ◽

Guimin Lu ◽

Jianguo Yu

Keyword(s):

Molecular Dynamics ◽

Ionic Conductivity ◽

Shear Viscosity ◽

Ion Pairs ◽

Liquid Structure ◽

Distribution Functions ◽

Dynamics Simulation ◽

Molten Chloride ◽

Ion Clusters ◽

Self Diffusion

Molten chloride salts are the main components in liquid metal batteries, high-temperature heat storage materials, heat transfer mediums, and metal electrolytes. In this paper, interest is centered on the influence of the LiCl component and temperature on the local structure and transport properties of the molten LiCl-NaCl-KCl system over the temperature range of 900 K to 1200 K. The liquid structure and properties have been studied across the full composition range by molecular dynamics (MD) simulation of a sufficient length to collect reliable values, such as the partial radial distribution function, angular distribution functions, coordination numbers distribution, density, self-diffusion coefficient, ionic conductivity, and shear viscosity. Densities obtained from simulations were underestimated by an average 5.7% of the experimental values. Shear viscosities and ionic conductivity were in good agreement with the experimental data. The association of all ion pairs (except for Li-Li and Cl-Cl) was weakened by an increasing LiCl concentration. Ion clusters were formed in liquids with increasing temperatures. The self-diffusion coefficients and ionic conductivity showed positive dependences on both LiCl concentration and temperature, however, the shear viscosity was the opposite. By analyzing the hydrodynamic radii of each ion and the coordination stability of cation-anion pairs, it was speculated that ion clusters could be the cation-anion coordinated structure and affected the macro properties.

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