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Title of Journal: Rheol Acta

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Abbravation: Rheologica Acta

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Springer Berlin Heidelberg

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1435-1528

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Rheological behaviour of a highmeltstrength poly

Authors: Daniel Raps Thomas Köppl Lutz Heymann Volker Altstädt
Publish Date: 2016/12/27
Volume: 56, Issue: 2, Pages: 95-111
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Abstract

The rheological properties of a long chain branched polypropylene LCBPP were investigated at the processing conditions of foam extrusion namely high pressure gas loading and high shear rates as well as in elongational deformation For measuring the rheological properties of PP at moderate and high deformation rates an inline rheometer was used Comparison of the results to standard rotational rheometry showed good agreement The effect of the processing parameters was quantified using shift factors for temperature pressure and gas concentration The influence of pressure on the shear viscosity was found to be of minor importance In contrast the shear viscosity was distinctly affected by CO2 concentration reducing it to one third of its gasfree value at a concentration of 6 wt at a specific shear rate The change of viscosity by a variation of temperature is similar in magnitude compared to the variation due to dissolved blowing agent Furthermore thermorheological complex behaviour was observed In the foaming process thermorheological complexity could contribute to a better morphology control of long chain branched polymers compared to linear ones The elongational viscosity was measured using both a hyperbolic die and a film stretching tool UXF for comparison It is almost three decades higher than the shear viscosity in the nonlinear region due to pronounced strain hardening of the meltThe financial support of the German Research Foundation DFG in the frame of the research project number Al 474/181 is highly acknowledged We also thank PD Dr Ulrich Handge Dr Sandra Aline Sanchez Vazquez and Prof HansMartin Laun for numerous scientific discussions Polypropylene was kindly provided by Borealis Polyolefine GmbH We thank Sebastian Gröschel and Markus Schirmer for experimental support


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  1. Effect of morphology on the interfacial slip of immiscible polypropylene/polystyrene blends
  2. Amorphous and crystalline states of ultrasoft colloids: a molecular dynamics study
  3. A hierarchical multi-mode MSF model for long-chain branched polymer melts part II: multiaxial extensional flows
  4. Novel bitumen/isocyanate-based reactive polymer formulations for the paving industry
  5. Can dynamical mechanical measurements predict brittle fracture behaviour?
  6. Self-reinforcement of polymers as a consequence of elongational flow
  7. The role of convective constraint release in parallel superposition flows of nearly monodisperse entangled polymer solutions
  8. Influence of the initial cooling temperature on the gelation and yield stress of waxy crude oils
  9. Molecular architecture and linear viscoelasticity of homogeneous ethylene/styrene copolymers
  10. Flow analysis of the weld line formation during injection mold filling of thermoplastics
  11. Squeeze flow of soft solids between rough surfaces
  12. Molecular orientation in non-Newtonian flow of dilute polymer solutions around spheres
  13. The contribution of frictional contacts to the shear strength of coarse glass bead powders and slurries
  14. End effects in rotational viscometry II. Pseudoplastic fluids at elevated Reynolds number
  15. The effect of premature wall yield on creep testing of strongly flocculated suspensions
  16. Rheological and morphological properties of PA6/ECO nanocomposites
  17. Orientation distribution in injection molding: a further step toward more accurate simulations
  18. Fractal analysis of viscoelastic data with automated gel point location and its potential application in the investigation of therapeutically modified blood coagulation
  19. Modeling confinement in polymer nanocomposites from linear viscoelasticity data
  20. Linear viscoelasticity of styrenic block copolymers–clay nanocomposites
  21. On exact solutions of the flow equations for Bingham visco-plastic fluids through an eccentric annular cross-section
  22. A computational extensional rheology study of two biofluid systems
  23. Power-law creep and residual stresses in a carbopol gel
  24. Electrorheological response of SnO 2 and Y 2 O 3 nanoparticles in silicon oil
  25. Generation of inkjet droplet of non-Newtonian fluid
  26. Scaling and mesostructure of Carbopol dispersions
  27. Study of the non-isothermal glass fibre drawing process
  28. Influence of molecular parameters on the stress dependence of viscous and elastic properties of polypropylene melts in shear
  29. An error-minimizing approach to inverse Langevin approximations

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