A simple improved mathematical model for polytetrafluoroethylene (PTFE) paste extrusion

Ardakani, Hesam Anvari; Mitsoulis, Evan; Hatzikiriakos, Savvas G.

doi:10.1016/j.ces.2012.11.040

Cited by 12 publications

(11 citation statements)

References 13 publications

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“…As discussed above the rheological behavior of PTFE pastes was examined in our previous work (Ardakani et al, 2013). Here we examine the mechanical properties of the extruded samples and its relation to fibrillation using aphenomenological simple mathematical model.…”

Section: Methodsmentioning

confidence: 99%

“…More details can be found in Ardakani et al (2013) on how the extrusion experiments were performed. Depending on the piston speed and die diameter, an apparent shear rate can be defined by _c A =32Q/ p D 3 a ,where Qisthe volumetric flow rate defined as the product of the piston speed, V p ,and the cross sectional area of the barrel, Q=V p ( p D 2 b )/4.…”

Section: Methodsmentioning

confidence: 99%

“…Phenomenological analytical flow models for calculating the extrusion pressure as af unction of the operating conditions and geometrical characteristicso fd ies are based on the \ radial-flow" hypothesis (Snelling and Lontz, 1960;Ariawan et al, 2002a;Patil et al, 2006a;Ardakani et al, 2013). This hypothesis assumes that the flow is along the radial direction in the die (assuming as pherical coordinate system as in Fig.…”

Section: P Henomenological Model For Fibrillationmentioning

confidence: 99%

“…Based on the \ radial-flow" hypothesis, the kinematics of PTFE flow can be calculated independent of any rheological constitutive law at agiven volumetric flow rate Q. Considering asimple constitutive equation for PTFE paste, an analytical expression for the extrusion pressure was derived by Ardakani et al (2013) which can be written as follows:…”

Section: P Henomenological Model For Fibrillationmentioning

confidence: 99%

“…In our previous work (Ardakani et al, 2013), we studied the rheology of polytetrafluoroethylene (PTFE) pastes using three capillary rheometers having barrels of different diameter and equipped with capillary dies of various designs. To describe the effects of die design for scale-up purposes (larger reservoir diameters), abasic phenomenological analytical mathematical model was developed and found to be consistent with experimental data.…”

Section: Introductionmentioning

confidence: 99%

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Polytetrafluoroethylene Paste Extrusion: A Fibrillation Model and Its Relation to Mechanical Properties

Ardakani

Mitsoulis

Hatzikiriakos

2013

International Polymer Processing

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The effects of process conditions on fibrillation and mechanical properties of polytetrafluoroethylene (PTFE) paste extrudates have been studied using capillary rheometers having barrels of different diameter and equipped with capillary dies of various designs. The tensile strength of PTFE extrudates is measured as afunction of apparent shear rate (flow rate), reduction ratio (cross sectional area of barrel to that of die), contraction angle, and diameter of the barrel. To describe the effects of die design on the quality of the final product, a basic phenomenological mathematical model has been developed. The model consists of asimple equation that explains fibril formation, due to the compression of PTFE resins, plus a kinetic equation, which is coupled with the \ radial-flow" hypothesis to predict the structure and the tensile strength of extrudates. The model predictions are found to be consistent with tensile strength measurements and SEM micrographs of the PTFE extrudates.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%