Nonlinear Viscoelastic Behavior of Concentrated Xanthan Gum Systems in Large Amplitude Oscillatory Shear (LAOS) Flow Fields : Stress Waveform and Lissajous Pattern Analysis

2016 ◽  
Vol 53 (5) ◽  
pp. 328-339
Author(s):  
Hye-Jin Ahn ◽  
Hoa-Youn Kuk ◽  
Ji-Seok Lee ◽  
Ki-Won Song
Keyword(s):  
Large Amplitude ◽  
Xanthan Gum ◽  
Pattern Analysis ◽  
Viscoelastic Behavior ◽  
Flow Fields ◽  
Oscillatory Shear ◽  
Large Amplitude Oscillatory Shear ◽  
Nonlinear Viscoelastic ◽  
Nonlinear Viscoelastic Behavior

scholarly journals Viscoelastic Rheological Behaviors of Polypropylene and LMPP Blends

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3485
Author(s):  
Feichao Zhu ◽  
Sohail Yasin ◽  
Munir Hussain
Keyword(s):  
Large Amplitude ◽  
Viscoelastic Behavior ◽  
Nonlinear Behavior ◽  
Oscillatory Shear ◽  
Large Amplitude Oscillatory Shear ◽  
Mechanical Responses ◽  
Nonlinear Viscoelastic ◽  
Linear Viscoelastic ◽  
Viscoelastic Behaviors ◽  
Linear And Nonlinear

Dynamic oscillatory shear testing is used to investigate polymeric viscoelastic behaviors. Small and large amplitude oscillatory shear tests are the canonical method for characterizing the linear and nonlinear viscoelastic behaviors of any polymeric material. With prominent and abundant work on linear viscoelastic studies, the nonlinear behavior is evasive in terms of generating infinite higher harmonics in the nonlinear regime. For this reason, intrinsic nonlinearities from large amplitude oscillatory shear (LAOS) studies have recently been used for insights on microstructural behaviors. This study is carried out for linear and nonlinear viscoelastic behavior with a main focus on LAOS of isostatic polypropylene (iPP) and relatively new low molecular weight and low modulus polypropylene-based polyolefin (LMPP) blends. The morphological results showed reduced spherulitic crystal nucleus size and increased distribution in blends with increasing LMPP. The blends showed subtle linear viscoelastic responses with strong nonlinear mechanical responses to variant strain and stress compared to pure iPP. The intracycle strain thickening and intracycle strain stiffening of high-content LMPP blends were comparatively dominant at medium strain amplitudes.

How Affine is the Entanglement Network of Molten Low-Density Polyethylene in Large Amplitude Oscillatory Shear?

1994 ◽  
Vol 116 (1) ◽  
pp. 14-18 ◽  
Author(s):  
A. J. Giacomin ◽  
R. S. Jeyaseelan
Keyword(s):  
Network Theory ◽  
Large Amplitude ◽  
Viscoelastic Behavior ◽  
Oscillatory Shear ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Large Amplitude Oscillatory Shear ◽  
Chain Molecules ◽  
Oscillatory Shear Flow ◽  
Nonlinear Viscoelastic

The nonlinear viscoelastic behavior of molten plastics is often attributed to interactions between long-chain molecules. Entanglement theories model this behavior with a network of junctions. Whether this network deforms differently than the liquid is a question of considerable interest to polymer engineers since nonlinear viscoelasticity governs many plastics processing operations. In this paper, large amplitude oscillatory shear flow is used to measure how affine the network deformation is relative to the deforming melt. For a low-density polyethylene melt, a small amount of nonaffine network deformation is observed when the large amplitude oscillations are analyzed with a nonaffine structural network theory. Inaccurate predictions were obtained from both the nonaffine network theory due to Phan-Thien, and the nonaffine network strand theory due to Larson.

The analysis of the influence of xanthan gum and apple pectins on egg white protein foams using the large amplitude oscillatory shear method

2016 ◽  
Vol 54 ◽  
pp. 293-301 ◽  
Author(s):  
Paweł Ptaszek ◽  
Maciej Kabziński ◽  
Anna Ptaszek ◽  
Kacper Kaczmarczyk ◽  
Joanna Kruk ◽  
...  
Keyword(s):  
Large Amplitude ◽  
Xanthan Gum ◽  
Egg White ◽  
Oscillatory Shear ◽  
Large Amplitude Oscillatory Shear ◽  
Egg White Protein

scholarly journals Field–Frequency-Dependent Non-linear Rheological Behavior of Magnetorheological Grease Under Large Amplitude Oscillatory Shear

2021 ◽  
Vol 8 ◽  
Author(s):  
Huixing Wang ◽  
Tianxiao Chang ◽  
Yancheng Li ◽  
Shaoqi Li ◽  
Guang Zhang ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Large Amplitude ◽  
Three Dimensional ◽  
Viscoelastic Behavior ◽  
Shear Thickening ◽  
Oscillatory Shear ◽  
Large Amplitude Oscillatory Shear ◽  
Field Frequency ◽  
Frequency Dependent ◽  
Non Linear

This article investigates the influence of frequency on the field-dependent non-linear rheology of magnetorheological (MR) grease under large amplitude oscillatory shear (LAOS). First, the LAOS tests with different driving frequencies were conducted on MR grease at four magnetic fields, and the storage and loss moduli under the frequency of 0.1, 0.5, 1, and 5 Hz were compared to obtain an overall understanding of the frequency-dependent viscoelastic behavior of MR grease. Based on this, the three-dimensional (3D) Lissajous curves and decomposed stress curves under two typical frequencies were depicted to provide the non-linear elastic and viscous behavior. Finally, the elastic and viscous measures containing higher harmonics from Fourier transform (FT)-Chebyshev analysis were used to quantitatively interpret the influence of the frequency on the non-linear rheology of MR grease, namely, strain stiffening (softening) and shear thickening (thinning), under LAOS with different magnetic fields. It was found that, under the application of the magnetic field, the onset of the non-linear behavior of MR grease was frequency-dependent. However, when the shear strain amplitude increased in the post-yield region, the non-linear rheology of MRG-70 was not affected by the oscillatory frequency.

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