High-Rate Extrusion of Pvdc Polymers

Jenkins, Steve; Powers, Joseph R.; Hyun, Kun S.; Naumovitz, J.A.

doi:10.1177/875608799000600203

Cited by 11 publications

(4 citation statements)

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“…The polymer melted in a 1D manner near the barrel surface. [ 2 ] Working in the Clarkson Extrusion Laboratory, Tang [ 21 ] observed that even for conventional high molecular weight polypropylene pellets, 1D melting would occur if the screw speed was extremely low, potentially producing a low pressure in the initial development of the melt film.…”

Section: Modeling Melting Dynamicsmentioning

confidence: 99%

“…A PVDC resin screw cross‐section that is melting via the 1D melting mechanism. Even at this early location in the melting process, the thickness of the melt film adjacent to the barrel wall was thicker than normal [ 2 ]…”

Section: Introductionmentioning

confidence: 99%

“…PVDC resins are difficult to process due in part to poor solids conveying and difficulties in forming a solid bed. [ 2 ] Relatively low pressures are often observed in the melting section of the screw, leading to poor compaction and conditions that are suitable for 1D melting.…”

Section: Introductionmentioning

confidence: 99%

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A proposed mechanism for solid bed encapsulation: Based on comparing three dimensional andone‐dimensionalscrew melting models

Campbell

Wetzel²,

Spalding

2022

Polymer Engineering & Sci

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This paper describes how the initial melt generation physics with differing pressure generation dynamics lead to either conventional melting or one dimensional (1D) melting. An historic review of the development of single screw melting models is presented. First, a review of the classic model is briefly presented. Second, after an analysis of literature melting data developed using the Maddock solidification procedure, a screw rotation concept melting model is presented that correlates very well with the melting analysis. Third, a new 1D film melting model is developed to analyze melting when the melt film does not encapsulate the solid bed. This physical model provides for the first time a quantitative model for the initiation and ultimate solid bed melting of the 1D melting process. Finally, a new concept and resulting model demonstrate that Reynold's barring concept for pressure generation in the initial melt film at the barrel interface may provide the mechanism that relates to whether the solid bed is or is not encapsulated.

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Section: Modeling Melting Dynamicsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A proposed mechanism for solid bed encapsulation: Based on comparing three dimensional andone‐dimensionalscrew melting models

Campbell

Wetzel²,

Spalding

2022

Polymer Engineering & Sci

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“…The copolymers currently used in the commercial process, such as poly vinylidene chloride‐ co ‐vinyl chloride (VDC‐VC copolymer), poly vinylidene chloride‐ co ‐methyl acrylate (VDC‐MA copolymer), and poly vinylidene chloride‐ co ‐acrylonitrile) (VDC‐AN copolymer), are less crystalline, more soluble, and have lower melting temperature and are easier to process than homo‐PVDC. Their most important applications are as packing film to limit oxygen/water vapor transport 1–4. However, new VDC copolymers with good gas barrier properties while maintaining other unique characteristics are still needed.…”

Section: Introductionmentioning

confidence: 99%

Preparation and characterization of vinylidene chloride‐co‐vinyl chloride copolymer/fluorinated synthetic mica nanocomposites I thermal and mechanical properties studies

Hsieh

Huang

et al. 2008

J Polym Sci B Polym Phys

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Poly(vinylidene chloride‐co‐vinylchloride)/organically modified fluorinated synthetic mica (MEE) (VDC‐VC/MEE) nanocomposites were prepared by melt blending of VDC‐VC copolymer with MEE, in the presence of dioctyl phthalate (DOP) which acted as a plasticizer and a cointercalating agent. The nanostructure, thermal, and dynamic mechanical properties of the VDC‐VC/MEE nanocomposites were studied by wide angle X‐ray diffractometer (WAXD), scanning electron microscope (SEM), transmission electron microscope (TEM), thermogravimetric analyzer (TGA), and dynamic mechanical analyzer (DMA). It was found that partially intercalated and partially exfoliated structures coexisted in VDC‐VC/MEE nanocomposities. Below 8 wt % MEE content, the intercalation effect of nanocomposites decreased with increasing the MEE content. Under a nitrogen atmosphere, VDC‐VC/MEE nanocomposites exhibited a single step thermal degradation behavior. The nanostructure of VDC‐VC/MEE can effectively prevent volatile gases from being released, and thus enhances its thermal stability. The thermal stability of VDC‐VC/MEE nanocomposites is strongly related to the morphology of nanocomposites and the degraded composites structure. DMA revealed a significant improvement in the storage modulus within the testing temperature range. The increase in storage modulus depends on the MEE content, which is attributed to the dispersed phase morphology. The glass transition temperature of VDC‐VC/MEE nanocomposites is affected by the chain mobility in the nanocomposites rather than the aggregative morphology. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1214–1225, 2008

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The effect of feeding mode on dispersive mixing efficiency in single‐screw extrusion

Elemans

Wunnik

2001

Polymer Engineering & Sci

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In the case of dry color compounds, where polymer pellets are coated with a pigment powder, the latter tends to form agglomerates during extrusion, owing to the hydrostatic pressure that prevails in the screw channels. In single‐screw extruders, this pressure is due to the Coulombic fricional transport in the solids conveying zone. The formation of agglomerates can be prevented to a considerable extent by operating the extruder in an underfed mode. This result has emerged from a study of the problems encountered when dispersing pigments in poly(butylene terephthalate) (PBT), but can also be applied in the case of numerous compounds where a fine dispersion of solids in polymers is required.

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High-Rate Extrusion of Pvdc Polymers

Abstract: The current extrusion technology for PVDC polymers is reviewed m detail Items covered include extruder screw design, controlled feeding, and screw temperature control The application of these principles to obtain rates of [185][186][187][188][189][190][191][192][193][194][195]

Cited by 11 publications

References 0 publications

A proposed mechanism for solid bed encapsulation: Based on comparing three dimensional andone‐dimensionalscrew melting models

A proposed mechanism for solid bed encapsulation: Based on comparing three dimensional andone‐dimensionalscrew melting models

Preparation and characterization of vinylidene chloride‐co‐vinyl chloride copolymer/fluorinated synthetic mica nanocomposites I thermal and mechanical properties studies

The effect of feeding mode on dispersive mixing efficiency in single‐screw extrusion

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