Development and Validation of a Recoverable Strain-Based Model for Flow-Induced Crystallization of Polymers

Zuidema, H Hans; Peters, Gwm Gerrit; Meijer, Heh Han

doi:10.1002/1521-3919(20010601)10:5<447::aid-mats447>3.0.co;2-c

Cited by 180 publications

(208 citation statements)

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“…The Janeschitz-Kriegl group found scaling laws for flowinduced nucleation density as a function of mechanical work [62]. Their approach was extended by the Peters group, who coupled flow-induced nucleation rate to backbone stretch [63][64][65][66]. Because the chains on the high side of the molecular weight distribution are most likely to be stretched, this effect is dominated by the longest chains in the material [21,29,63,67], that is, in a multimode viscoelastic model by the mode with the highest relaxation time(s).…”

Section: State Of the Artmentioning

confidence: 99%

“…Their approach was extended by the Peters group, who coupled flow-induced nucleation rate to backbone stretch [63][64][65][66]. Because the chains on the high side of the molecular weight distribution are most likely to be stretched, this effect is dominated by the longest chains in the material [21,29,63,67], that is, in a multimode viscoelastic model by the mode with the highest relaxation time(s). Based on an extension of the Schneider rate equations [68] proposed by Eder and coworkers [18,69], Zuidema et al proposed a model that calculates shish density (i.e., the line nucleation density for kebabs) from continuum-level deformation [63].…”

Section: State Of the Artmentioning

confidence: 99%

“…Based on an extension of the Schneider rate equations [68] proposed by Eder and coworkers [18,69], Zuidema et al proposed a model that calculates shish density (i.e., the line nucleation density for kebabs) from continuum-level deformation [63]. Their model was validated to capture accurately the shear layer thickness in a number of experiments [63,66]. Several other authors have adapted an expression for free energy to incorporate deformation and derive nucleation rate [38,[70][71][72][73][74][75][76].…”

Section: State Of the Artmentioning

confidence: 99%

“…Liedauer et al coupled the parameter _ γ 4 t 2 s , with shear rate _ γ : and flow time t s , to the density of shish [18], see also [69]. Their approach was used as a starting point for the Eindhoven group, who linked nucleation rate to deformation of the high molecular weight mode on a continuum level [21,29,63] and subsequent shish growth (after overcoming a critical flow criterion) to deformation of a mode corresponding to the average molecular weight [63,64,66]. This approach was validated in terms of shear layer thickness in both channel flow and capillary rheometer.…”

Section: Formation Of Multiple Morphologies At High Shear Ratesmentioning

confidence: 99%

“…Therefore, the total line nucleation density for kebabs (i.e., the specific shish length) is given by Reproduced with permission of the copyright owner [5] Note that there is no critical flow condition for the formation of shish, as was used in previous versions of FIC modeling [63]. However, for weak to mild flow conditions, no shish creation is observed because both nucleation rate _ N f and propagation rate _ L : are low for such flow conditions.…”

Section: Structure Formationmentioning

confidence: 99%

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Modeling Flow-Induced Crystallization

Roozemond

Drongelen

Peters

2016

Polymer Crystallization II

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A numerical model is presented that describes all aspects of flow-induced crystallization of isotactic polypropylene at high shear rates and elevated pressures. It incorporates nonlinear viscoelasticity, including viscosity change as a result of formation of oriented fibrillar crystals (shish), compressibility, and nonisothermal process conditions caused by shear heating and heat release as a result of crystallization. In the first part of this chapter, the model is validated with experimental data obtained in a channel flow geometry. Quantitative agreement between experimental results and the numerical model is observed in terms of pressure drop, apparent crystallinity, parent/daughter ratio, Hermans' orientation, and shear layer thickness. In the second part, the focus is on flow-induced crystallization of isotactic polypropylene at elevated pressures, resulting in multiple crystal phases and morphologies. All parameters but one are fixed a priori from the first part of the chapter. One additional parameter, determining the portion of β-crystal spherulites nucleated by flow, is introduced. By doing so, an accurate description of the fraction of β-phase crystals is obtained. The model accurately captures experimental data for fractions of all crystal phases over a wide range of flow conditions (shear rates from 0 to 200 s À1 , pressures from 100 to 1,200 bar, shear temperatures from 130 C to 180 C). Moreover, it is shown that, for high shear rates and pressures, the measured γ-phase fractions can only be matched if γ-crystals can nucleate directly on shish.

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Section: State Of the Artmentioning

confidence: 99%

Section: State Of the Artmentioning

confidence: 99%

Section: State Of the Artmentioning

confidence: 99%

Section: Formation Of Multiple Morphologies At High Shear Ratesmentioning

confidence: 99%

Section: Structure Formationmentioning

confidence: 99%

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Modeling Flow-Induced Crystallization

Roozemond

Drongelen

Peters

2016

Polymer Crystallization II

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Plastics Properties: Physical, Mechanical, and Degradation Aspects

Buekens

2019

Kirk-Othmer Encyclopedia of Chemical Technology

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Plastic materials (and their additives) are selected for a particular application on the basis of quality, cost, and performance, established by standardized test procedures. This article centers on the physical and mechanical properties of plastics and their evaluation. Following an introduction on plastics, their macromolecular structures, and composition, properties, such as density, viscosity, diffusion and barrier properties, moisture and ash content, viscoelastic properties and their testing, and plastic degradation are discussed. Testing methods of materials properties, to make sure that they meet technical requirements, are also discussed. The article guides the reader in selecting plastic materials for given applications, by considering systematically important properties and the way they relate to operating conditions and quality.

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