Rheotens‐mastercurves and drawability of polymer melts

Wagner, Manfred H.; Schulze, V.; Göttfert, A.

doi:10.1002/pen.10480

Cited by 70 publications

(41 citation statements)

References 20 publications

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“…The horizontal shifting of the s 11 /l diagram results from the orientation of the mesogens of the LCP melt in the rectangular slit die. This elongation behavior was previously reported by Wagner [1] for polymer melts with flexible chains.…”

Section: Influence Of Pre-shearing On Elongational Behaviorsupporting

confidence: 88%

Strain-Induced Orientation States and Nucleation of Line Disclinations in a Thermotropic Liquid Crystalline Polymer Melt

Geiger¹

1998

Chem. Eng. Technol.

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A suitable model for the jet cutting process has been developed from which an effective method for the reduction of losses by inclination of the cutting wires' plane was derived. Using diagonal cutting and small cutting wires in a circular stabilized cutting tool, the overall losses could be reduced significantly below 5%. Regarding these improvements and the simplicity of a scale-up process, the jet cutting method should be suitable for industrial application, e.g., for the manufacture of catalysts or chromatographic materials.

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Section: Influence Of Pre-shearing On Elongational Behaviorsupporting

confidence: 88%

Strain-Induced Orientation States and Nucleation of Line Disclinations in a Thermotropic Liquid Crystalline Polymer Melt

Geiger¹

1998

Chem. Eng. Technol.

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“…The measured elongational flow properties are affected by the molecular weight and structure of the polymers used, as well as the draw ratio, test temperature, roller speed, and die geometry. [1][2][3] Viscoelastic behavior of the polymer melt under extensional deformation is usually expected at low draw ratios, but it may reach the viscous behavior when the stretching level or draw ratio is sufficiently high [4] A number of studies on measurements of elongational flow properties using various techniques have been given in the literature. [1][2][3][4][5][6][7][8][9][10] Therefore, they are not detailed in this work.…”

Section: Introductionmentioning

confidence: 99%

Effects of Roller Speed, Die Temperature, Volumetric Flow Rate, and Multiple Extrusions on Mechanical Strength of Molten and Solidified LDPE under Tensile Deformation

Harnnarongchai

Intawong

Sombatsompop

2011

Journal of Macromolecular Science, Part B

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An experimental rig coupled with a high speed data-logging and recording system and a personal computer was specially designed and constructed for the real-time measurement of mechanical strength (in terms of drawdown force) as a function of volumetric flow rate and roller speed for virgin low-density polyethylene (LDPE) and reprocessed LDPE during a filament stretching process. The effect of the number of extrusion passes for the reprocessed LDPE was our main interest. The experimental rig was connected to the end of a single-screw extruder, which was used to melt and extrude the polymers. The LDPE filaments were then solidified and collected for studying the mechanical properties. The mechanical strength of the virgin LDPE and reprocessed LDPE were investigated in both molten and solidified states. The mechanical strengths of the virgin and reprocessed LDPEs under these two states are discussed and compared in terms of change in magnitude under a wide range of processing conditions (volumetric flow rate, die temperature, and roller speed). The results suggested that in the molten state the drawdown force for LDPE melts was dependent on volumetric flow rate, die temperature, roller speed, and the number of reprocessing passes. The drawdown force being affected by the number of reprocessing passes could be explained by molecular degradation and gelation effects when using high volumetric flow rates. In the solidified state, the tensile properties of the solidified LDPE increased with roller speed. The effect of the number of extrusion passes for the solidified LDPE was similar to that for the molten LDPE. In the case of volumetric flow rates, the mechanical properties of the solidified LDPE decreased with increasing volumetric flow rate, whereas those of the molten LDPE exhibited the opposite effect. Thus, the mechanical strength of the molten LDPE could not always be used to assess the mechanical properties of the solidified LDPE.

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“…A Göttfert Rheotens [40] instrument was situated below the X-ray position to provide a constant haul-off speed on the extruded tape for each experiment. The haul-off speeds were varied at each chosen height between 3.0 and 50.4 m/min.…”

Section: Extruder Instrumentationmentioning

confidence: 99%

“…Here, in-line SAXS was used to monitor the crystallinity, orientation and structure development of the LDPE tape with respect to varying processing parameters: haul-off speed and distance down the tapeline. The elongation of the extruded tape was controlled by employing a Rheotens instrument [40] which also allows the draw-down force to be measured enabling the direct evaluation of stress experienced by the tape. This removes the need for take-up rolls where the tape is constantly wound-up, which can change the draw-down speed during the SAXS data acquisition.…”

Section: Introductionmentioning

confidence: 99%

Effect of processing parameters on the morphology development during extrusion of polyethylene tape: An in-line small-angle X-ray scattering (SAXS) study

Heeley

Gough

Hughes

et al. 2013

Polymer

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Ray scattering (SAXS). AbstractThe in-line development of crystalline morphology and orientation during melt extrusion of low density polyethylene (LDPE) tape at nil and low haul-off speeds has been investigated using Small-Angle X-Ray Scattering (SAXS). The processing parameters, namely haul-off speed and distance down the tape-line have been varied and the resulting crystalline morphology is described from detailed analysis of the SAXS data. Increasing haul-off speed increased orientation in the polymer tape and the resulting morphology could be described in terms of regular lamellar stacking perpendicular to the elongation direction. In contrast, under nil haul-off conditions the tape still showed some orientation down the tape-line, but a shish-kebab structure prevails. The final lamellae thickness (~50 Å) and bulk crystallinity (~20%), were low for all processing conditions investigated, which is attributed to the significant shortchain branching in the polymer acting as point defects limiting lamellae crystal growth.2

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Rheotens‐mastercurves and drawability of polymer melts

Cited by 70 publications

References 20 publications

Strain-Induced Orientation States and Nucleation of Line Disclinations in a Thermotropic Liquid Crystalline Polymer Melt

Strain-Induced Orientation States and Nucleation of Line Disclinations in a Thermotropic Liquid Crystalline Polymer Melt

Effects of Roller Speed, Die Temperature, Volumetric Flow Rate, and Multiple Extrusions on Mechanical Strength of Molten and Solidified LDPE under Tensile Deformation

Effect of processing parameters on the morphology development during extrusion of polyethylene tape: An in-line small-angle X-ray scattering (SAXS) study

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