Validity of the modified molecular stress function theory to predict the rheological properties of polymer nanocomposites

2013 ◽  
Vol 57 (3) ◽  
pp. 881-899 ◽  
Author(s):  
Hojjat Mahi Hassanabadi ◽  
Mahdi Abbasi ◽  
Manfred Wilhelm ◽  
Denis Rodrigue
Keyword(s):  
Rheological Properties ◽  
Polymer Nanocomposites ◽  
Stress Function ◽  
Function Theory ◽  
Molecular Stress Function ◽  
Molecular Stress Function Theory

Modeling strain hardening of polydisperse polystyrene melts by molecular stress function theory

2004 ◽  
Vol 44 (3) ◽  
pp. 235-243 ◽  
Author(s):  
M. H. Wagner ◽  
S. Kheirandish ◽  
K. Koyama ◽  
A. Nishioka ◽  
A. Minegishi ◽  
...  
Keyword(s):  
Strain Hardening ◽  
Stress Function ◽  
Function Theory ◽  
Molecular Stress Function ◽  
Molecular Stress Function Theory

scholarly journals Intra-Cycle Elastic Nonlinearity of Nitrogen-Doped Carbon Nanotube/Polymer Nanocomposites under Medium Amplitude Oscillatory Shear (MAOS) Flow

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1257 ◽  
Author(s):  
Milad Kamkar ◽  
Soheil Sadeghi ◽  
Mohammad Arjmand ◽  
Ehsan Aliabadian ◽  
Uttandaraman Sundararaj
Keyword(s):  
Rheological Properties ◽  
Polymer Nanocomposites ◽  
Polyvinylidene Fluoride ◽  
Viscoelastic Behavior ◽  
Oscillatory Shear ◽  
Dispersed Systems ◽  
Nitrogen Doped ◽  
Elastic Nonlinearity ◽  
Medium Amplitude Oscillatory Shear ◽  
Nitrogen Doped Carbon

This study seeks to unravel the effect of carbon nanotube’s physical and chemical features on the final electrical and rheological properties of polymer nanocomposites thereof. Nitrogen-doped carbon nanotubes (N-CNTs) were synthesized over two different types of catalysts, i.e., Fe and Ni, employing chemical vapor deposition. Utilizing this technique, we were able to synthesize N-CNTs with significantly different structures. As a result, remarkable differences in the network structure of the nanotubes were observed upon mixing the N-CNTs in a polyvinylidene fluoride (PVDF) matrix, which, in turn, led to drastically different electrical and rheological properties. For instance, no enhancement in the electrical conductivity of poorly-dispersed (N-CNT)Ni/PVDF samples was observed even at high nanotube concentrations, whereas (N-CNT)Fe/PVDF nanocomposites exhibited an insulative behavior at 1.0 wt%, a semi-conductive behavior at 2.0 wt%, and a conductive behavior at 2.7 wt%. In terms of rheology, the most substantial differences in the viscoelastic behavior of the systems were distinguishable in the medium amplitude oscillatory shear (MAOS) region. The stress decomposition method combined with the evaluation of the elastic and viscous third-order Chebyshev coefficients revealed a strong intra-cycle elastic nonlinearity in the MAOS region for the poorly-dispersed systems in small frequencies; however, the well-dispersed systems showed no intra-cycle nonlinearity in the MAOS region. It was shown that the MAOS elastic nonlinearity of poorly-dispersed systems stems from the confinement of N-CNT domains between the rheometer’s plates for small gap sizes comparable with the size of the agglomerates. Moreover, the intra-cycle elastic nonlinearity of poorly-dispersed systems is frequency-dependent and vanished at higher frequencies. The correlation between the microstructure and viscoelastic properties under large shear deformations provides further guidance for the fabrication of high-performance 3D-printed electrically conductive nanocomposites with precisely controllable final properties for engineering applications.

Solution of Plane Problems of Elasticity Utilizing Partitioning Concepts

1973 ◽  
Vol 40 (3) ◽  
pp. 767-772 ◽  
Author(s):  
O. L. Bowie ◽  
C. E. Freese ◽  
D. M. Neal
Keyword(s):  
Analytic Function ◽  
Power Series ◽  
Collocation Method ◽  
Stress Function ◽  
Function Theory ◽  
Series Expansions ◽  
Two Dimensional ◽  
Numerical Examples ◽  
Power Series Expansions

A partitioning plan combined with the modified mapping-collocation method is presented for the solution of awkward configurations in two-dimensional problems of elasticity. It is shown that continuation arguments taken from analytic function theory can be applied in the discrete to “stitch” several power series expansions of the stress function in appropriate subregions of the geometry. The effectiveness of such a plan is illustrated by several numerical examples.

Analysis of Mode III Collinear Periodic Cracks-Tip Stress Field of an Infinite Orthotropic Plate

2012 ◽  
Vol 446-449 ◽  
pp. 2080-2084 ◽  
Author(s):  
Xue Xia Zhang ◽  
Chan Li ◽  
Xiao Chao Cui ◽  
Wen Bin Zhao
Keyword(s):  
Crack Length ◽  
Stress Function ◽  
Function Theory ◽  
Complex Function ◽  
Mode Iii ◽  
Mechanical Problem ◽  
Complex Function Theory ◽  
Plane Shear ◽  
Periodic Cracks ◽  
The Given

The cracks-tip field on collinear periodic cracks of infinite orthotropic fiber reinforcement composite plate subjected to anti-plane shear force is studied in this paper. With the introduction of the Westergaard stress function and application of complex function theory and undetermined coefficients method, mechanical problem is changed into partial differential boundary value problem. The undetermined coefficients and the stress function are obtained with the help of boundary conditions. Due to the distribution of periodic cracks, stress intensity factor depends on the shape factor. The results show that interaction happens between the collinear periodic cracks. When the ratio of crack length and crack spacing is less than 1/3, the interaction between the cracks is very small. When the ratio gradually increases to 1, strong interaction between the cracks will be found. Cracks-tip field has scale effect. When the ratio of crack length and the given reference crack length decreases, the displacement field is significantly smaller.

Sign in / Sign up

Export Citation Format

Share Document