Small-Amplitude Oscillatory Shear Flow Measurements as a Tool To Detect Very Low Amounts of Long Chain Branching in Polyethylenes

1998 ◽  
Vol 31 (11) ◽  
pp. 3639-3647 ◽  
Author(s):  
J. F. Vega ◽  
A. Santamaría ◽  
A. Muñoz-Escalona ◽  
P. Lafuente
Keyword(s):  
Shear Flow ◽  
Small Amplitude ◽  
Oscillatory Shear ◽  
Chain Branching ◽  
Flow Measurements ◽  
Small Amplitude Oscillatory Shear ◽  
Long Chain Branching ◽  
Oscillatory Shear Flow ◽  
Long Chain

scholarly journals Large-amplitude oscillatory shear flow loops for long-chain branching from general rigid bead-rod theory

2020 ◽  
Vol 32 (5) ◽  
pp. 053102 ◽  
Author(s):  
M. A. Kanso ◽  
A. J. Giacomin ◽  
C. Saengow
Keyword(s):  
Shear Flow ◽  
Large Amplitude ◽  
Oscillatory Shear ◽  
Large Amplitude Oscillatory Shear ◽  
Chain Branching ◽  
Long Chain Branching ◽  
Rod Theory ◽  
Oscillatory Shear Flow ◽  
Long Chain

Numerical simulations of small amplitude oscillatory shear flow of suspensions of rigid particles in non-Newtonian liquids at finite inertia

2021 ◽  
Vol 65 (5) ◽  
pp. 821-835
Author(s):  
Massimiliano M. Villone ◽  
Marco E. Rosti ◽  
Outi Tammisola ◽  
Luca Brandt
Keyword(s):  
Shear Flow ◽  
Numerical Simulations ◽  
Small Amplitude ◽  
Oscillatory Shear ◽  
Small Amplitude Oscillatory Shear ◽  
Rigid Particles ◽  
Oscillatory Shear Flow ◽  
Newtonian Liquids

Drop deformation under small-amplitude oscillatory shear flow

2003 ◽  
Vol 42 (1-2) ◽  
pp. 1-9 ◽  
Author(s):  
Riccardo Cavallo ◽  
Stefano Guido ◽  
Marino Simeone
Keyword(s):  
Shear Flow ◽  
Small Amplitude ◽  
Oscillatory Shear ◽  
Drop Deformation ◽  
Small Amplitude Oscillatory Shear ◽  
Oscillatory Shear Flow

Influence of molecular structure on the foamability of polypropylene: Linear and extensional rheological fingerprint

2017 ◽  
Vol 54 (3) ◽  
pp. 515-543 ◽  
Author(s):  
Ebrahim Bahreini ◽  
Seyed Foad Aghamiri ◽  
Manfred Wilhelm ◽  
Mahdi Abbasi
Keyword(s):  
Molecular Structure ◽  
Small Amplitude ◽  
Function Model ◽  
Chain Branching ◽  
Small Amplitude Oscillatory Shear ◽  
Long Chain Branching ◽  
Molecular Stress Function ◽  
Branched Polypropylene ◽  
Long Chain ◽  
Long Chain Branched Polypropylene

The foaming structure and rheological properties of four different isotactic homo-polypropylenes with various molecular weights and an isotactic long chain branched polypropylene were investigated to find a suitable rheological fingerprint for PP foams. The molecular weight distribution and thermal properties were measured using GPC-MALLS and differential scanning calorimetry, respectively. Small amplitude oscillatory shear data and uniaxial extensional experiments were analyzed using the frameworks of van Gurp-Palmen plot (δ vs. | G*|) and the molecular stress function model, respectively. These analyses were used to find a correlation between the molecular structure, rheological properties and foaming structures of linear and long chain branching polypropylenes. Two linear viscoelastic characteristics, | G*| at δ = 60° and | η*| at ω = 5 rad/s were used as criteria for foamability of these polymers, where decreasing of both parameters by increasing the long chain branching content results in smaller cell size and higher cell density. The molecular stress function model was able to quantify the strain hardening properties of long chain branching blends using small amplitude oscillatory shear data and two nonlinear material parameters, 1 ≤  β ≤ 2.2 and 1 ≤ [Formula: see text] ≤ 600, where the minimum and maximum values of these parameters belong to the linear and long chain branched polypropylene, respectively. Increasing the long chain branched polypropylene content of the PP blends increased strain hardening, and therefore improved the foaming characteristics significantly by suppressing the coalescence of cells. Dilution of linear PP with only 10 wt% of long chain branched polypropylene enhanced the cell density from 5.7 × 106 to 2.7 × 107 cell/cm3 and reduced the average cell diameter from 58 to 26 µm, respectively, while their volume expansion ratio remained in the same range of 2–3. Increasing of long chain branching to 50 and 100 wt% enhanced the V.E.R. to 6.2 and 7.8, respectively.

scholarly journals Direct numerical simulation of a bubble suspension in small amplitude oscillatory shear flow

2017 ◽  
Vol 56 (6) ◽  
pp. 555-565 ◽  
Author(s):  
Christos Mitrias ◽  
Nick O. Jaensson ◽  
Martien A. Hulsen ◽  
Patrick D. Anderson
Keyword(s):  
Numerical Simulation ◽  
Shear Flow ◽  
Direct Numerical Simulation ◽  
Small Amplitude ◽  
Oscillatory Shear ◽  
Small Amplitude Oscillatory Shear ◽  
Oscillatory Shear Flow

Long-Chain Branching in Metallocene-Catalyzed Polyethylenes Investigated by Low Oscillatory Shear and Uniaxial Extensional Rheometry

2002 ◽  
Vol 35 (3) ◽  
pp. 1038-1048 ◽  
Author(s):  
Anneli Malmberg ◽  
Claus Gabriel ◽  
Thomas Steffl ◽  
Helmut Münstedt ◽  
Barbro Löfgren
Keyword(s):  
Oscillatory Shear ◽  
Chain Branching ◽  
Long Chain Branching ◽  
Extensional Rheometry ◽  
Long Chain

Effect of Short-Chain Branching on the Melt Behavior of Polypropylene Under Small-Amplitude Oscillatory Shear Conditions

2012 ◽  
Vol 214 (1) ◽  
pp. 107-116 ◽  
Author(s):  
Humberto Palza ◽  
Raúl Quijada ◽  
Manfred Wilhelm
Keyword(s):  
Small Amplitude ◽  
Oscillatory Shear ◽  
Short Chain ◽  
Chain Branching ◽  
Small Amplitude Oscillatory Shear
Sign in / Sign up

Export Citation Format

Share Document