Collective viscosity model for shear thinning polymeric materials

Kim, Sun Kyoung

doi:10.1007/s00397-019-01180-w

Cited by 12 publications

(10 citation statements)

References 26 publications

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“…While a number of studies demonstrate an ability to perform these measurements, they do not agree on their accuracy and application to studying the rheological behavior of the polymer, most likely due to the transient nature of the printing process. , More definitive and consistent measurement techniques are vital to furthering the understanding of various behaviors inside the nozzle that will translate to the properties in the stand-off region and subsequent deposition. Finally, since multimaterial extrusion is gaining popularity in the 3D printing community, collective viscosity models that can predict the shear viscosities inside the nozzle for different polymer melts must be studied in the context of MatEx …”

Section: Discussion and Future Outlookmentioning

confidence: 99%

“…Finally, since multimaterial extrusion is gaining popularity in the 3D printing community, collective viscosity models that can predict the shear viscosities inside the nozzle for different polymer melts must be studied in the context of MatEx. 170 Stand-Off Region. Although significant experimental and numerical research has been realized for the MatEx process in the standoff region, die swelling, and strand deposition, further work needs to be performed to investigate the effects of additional nozzle configuration with different angularity, gap, and cylindricity as well as speed ratio on the cross-section of the strand.…”

Section: J T T T T ( )mentioning

confidence: 99%

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Importance of Polymer Rheology on Material Extrusion Additive Manufacturing: Correlating Process Physics to Print Properties

Das

Gilmer

Biria

et al. 2021

ACS Appl. Polym. Mater.

130

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Recent advances in the field of additive manufacturing (AM) or 3D printing, have garnered serious interest for its potential to substitute time-consuming and costly subtractive and formative manufacturing techniques. Material extrusion (MatEx), employing filament and pelletbased feedstocks, is an AM technique for fabricating three-dimensional objects dictated by a computer-aided design (CAD) file in a layer-by-layer manner. Being inherently a "melt-and-form" technique, the physics of MatEx is strongly dependent on the melt flow behavior of the polymers and hence on their rheology. The focus of this review article is to analyze the current progress in rheological characterizations of filament and pellet-based polymeric feedstocks for application in MatEx. The importance of shear and temperature-dependent viscosities in relation to consistent extrusion through the print nozzle and in the standoff region between nozzle and bed will be highlighted. The importance of shear and/or extensional viscosities and extent of die swell (upon exit from the nozzle) experienced by the polymers under processing parameters relevant to MatEx will be investigated. Postextrusion from the nozzle, the rheological characteristics of the viscous polymer melt as it cools once deposited on the print bed governs the degree of interlayer welding, that impacts the mechanical performance of the printed parts. Controlling and monitoring rheological properties such as zero-shear viscosities and shear moduli of the melt is of significant importance in this region in order to ensure proper mechanical robustness and shape integrity of the deposited layers. Both experimental and theoretical approaches based on polymer chain reptation mechanisms will be reviewed in detail and suggestions to address the existing limitations associated with the process will be provided. Fundamental understanding of the correlation between the classical theories and current understanding based on recent experimentation and analysis is expected to assist the design and development of the next generation of polymer feedstocks and machine designs for MatEx-based AM.

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Section: Discussion and Future Outlookmentioning

confidence: 99%

Section: J T T T T ( )mentioning

confidence: 99%

Importance of Polymer Rheology on Material Extrusion Additive Manufacturing: Correlating Process Physics to Print Properties

Das

Gilmer

Biria

et al. 2021

ACS Appl. Polym. Mater.

130

View full text Add to dashboard Cite

show abstract

“…Overall the model was in good agreement with the experimental data with an average mean relative standard deviation is of 1.97 %. [129] More recently Kim [146] developed a viscosity model that is a combination of conventional viscosity models. The proposed models are based on the hypothesis that polymeric systems can be regarded as a composition of rheological blocks that are linked due to the sharing of some properties.…”

Section: Non-newtonian Modelsmentioning

confidence: 99%

“…The Combined model was able to correct discrepancies that were observed with the power law to Cross model for the polysaccharide solutions. [146] …”

Section: Viscosity Of Polymer Solutionsmentioning

confidence: 99%

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State‐Of‐The‐Art Quantification of Polymer Solution Viscosity for Plastic Waste Recycling

et al. 2021

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Solvent-based recycling is a promising approach for closed-loop recovery of plastic-containing waste. It avoids the energy cost to depolymerize the plastic but still allows to clean the polymer of contaminants and additives. However, viscosity plays an important role in handling the polymer solutions at high concentrations and in the cleaning steps. This Review addresses the viscosity behavior of polymer solutions, available data, and (mostly algebraic) models developed. The non-Newtonian viscosity models, such as the Carreau and Yasuda-Cohen-Armstrong models, pragmatically describe the viscosity of polymer solutions at different concentrations and shear rate ranges. This Review also describes how viscosity influences filtration and centrifugation processes, which are crucial steps in the cleaning of the polymer and includes a polystyrene/ styrene case study.

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Darcy friction factor and Nusselt number in laminar tube flow of Carreau fluid

Kim

2022

Rheol Acta

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Collective viscosity model for shear thinning polymeric materials

Cited by 12 publications

References 26 publications

Importance of Polymer Rheology on Material Extrusion Additive Manufacturing: Correlating Process Physics to Print Properties

Importance of Polymer Rheology on Material Extrusion Additive Manufacturing: Correlating Process Physics to Print Properties

State‐Of‐The‐Art Quantification of Polymer Solution Viscosity for Plastic Waste Recycling

Darcy friction factor and Nusselt number in laminar tube flow of Carreau fluid

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