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Wide-Angle X-Ray, Densitometric and Microscopical Studies on Injection Molded Polypropylene Disks

  • P. Zipper , A. Jánosi , E. Wrentschur , W. Geymayer , E. Ingolic , W. Friesenbichler and F. Eigl
Published/Copyright: June 22, 2013
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International Polymer Processing
From the journal International Polymer Processing Volume 12 Issue 2

Abstract

Circular disks (280 mm diameter, 2 mm thickness) were injection molded from two grades of isotactic polypropylene under systematic variation of processing parameters (melt temperature, mold temperature, flow rate, packing pressure, and packing time) according to a two-level fractional factorial design. The disks showed ring-shaped zones (“halos”) of enhanced turbidity. The wide-angle X-ray scattering of the disks was measured as a function of the distance from the gate at 13 positions along the radius, using a diffractometer and reflection geometry. These measurements yielded radial profiles of the orientation of α-PP and of the distribution of β-PP crystallites. Both kinds of profiles revealed clear correlations with the polymer grade and with the melt and/or mold temperature. Radial profiles of optical turbidity of the disks were obtained by means of a microdensitometer. Pronounced maxima of turbidity were found to coincide with the maxima observed in the radial distribution of β-PP. An analysis of variance (ANOVA) of the experiments showed that the mass temperature has the greatest influence on the radial distances of the maxima of turbidity. Increasing mass temperature led to decreasing radial distances of the turbidity maxima, whereas the mold temperature as well as the flow rate only had a small influence on the radial positions of the turbidity maxima. The investigation of cross-sections, which were taken from some disks at selected distances from gate, by means of optical microscopy using polarized light revealed significant changes in the morphology with increasing distance from gate, e.g., changes in the size and distribution of β-PP spherulites.

* Mail address: Prof. Dr. Peter Zipper, Institut fur Physikalische Chemie, Universität Graz, Heinrichstrasse 28, A-8010 Graz, Austria
Received: 1997-1-21
Accepted: 1997-1-22
Published Online: 2013-06-22
Published in Print: 1997-05-01

© 1997, Carl Hanser Verlag, Munich

Articles in the same Issue

  1. Contents
  2. Contents
  3. Editorial
  4. Third in a Series: Pioneers of Polymer Processing: Charles Goodyear
  5. Screw Extrusion/Mixing
  6. Chaotic Features of Flow in Polymer Processing Equipment-Relevance to Distributive Mixing
  7. Influence of Design on Mixing Efficiency in a Variable Intermeshing Clearance Mixer
  8. Simulation of Non-Isothermal Flow in a Modular Buss Kneader and Comparison with Experiment
  9. Rheological Behaviour of LLDPE/LDPE Blends under Elongational Deformation
  10. Effect of Compounding Conditions on Mechanical Properties of Glass Fiber-Reinforced Polyamide-6
  11. Die Extrusion
  12. A New Approach to Simulation of Die Flow which Incorporates the Extruder and Rotating Screw Tips in the Analysis
  13. New Aspects Concerning the Design of Coathanger Dies
  14. Film
  15. On-Line Birefringence Measurement in Film Blowing of a Linear Low Density Polyethylene
  16. Brittle Melt Rupture Phenomena in Polymer Processing
  17. Moulding
  18. Injection Molding of LDPE/BaSO4 Blends
  19. An Experimental Study of Rotational Molding of Polypropylene/Polyethylene Copolymers
  20. Determination of the Inter-Relationships Between Processing Conditions and Properties of an Injection Molded Silicone Ring Using an Experimental Design
  21. Numerical Simulation of the Flow and Fiber Orientation in Reinforced Thermoplastic Injection Molded Products
  22. Wide-Angle X-Ray, Densitometric and Microscopical Studies on Injection Molded Polypropylene Disks
https://doi.org/10.3139/217.970192

Articles in the same Issue

  1. Contents
  2. Contents
  3. Editorial
  4. Third in a Series: Pioneers of Polymer Processing: Charles Goodyear
  5. Screw Extrusion/Mixing
  6. Chaotic Features of Flow in Polymer Processing Equipment-Relevance to Distributive Mixing
  7. Influence of Design on Mixing Efficiency in a Variable Intermeshing Clearance Mixer
  8. Simulation of Non-Isothermal Flow in a Modular Buss Kneader and Comparison with Experiment
  9. Rheological Behaviour of LLDPE/LDPE Blends under Elongational Deformation
  10. Effect of Compounding Conditions on Mechanical Properties of Glass Fiber-Reinforced Polyamide-6
  11. Die Extrusion
  12. A New Approach to Simulation of Die Flow which Incorporates the Extruder and Rotating Screw Tips in the Analysis
  13. New Aspects Concerning the Design of Coathanger Dies
  14. Film
  15. On-Line Birefringence Measurement in Film Blowing of a Linear Low Density Polyethylene
  16. Brittle Melt Rupture Phenomena in Polymer Processing
  17. Moulding
  18. Injection Molding of LDPE/BaSO4 Blends
  19. An Experimental Study of Rotational Molding of Polypropylene/Polyethylene Copolymers
  20. Determination of the Inter-Relationships Between Processing Conditions and Properties of an Injection Molded Silicone Ring Using an Experimental Design
  21. Numerical Simulation of the Flow and Fiber Orientation in Reinforced Thermoplastic Injection Molded Products
  22. Wide-Angle X-Ray, Densitometric and Microscopical Studies on Injection Molded Polypropylene Disks
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