In-Line Density Monitoring of Rigid PVC Foam during Extrusion Process
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N. H. Abu-Zahra
Abstract
An ultrasound-based sensor has been investigated to monitor the density of rigid PVC foam, in-line, during the extrusion process. A 2.25 MHz ultrasound transducer was used to measure the acoustic properties; i.e. speed of sound, acoustic impedance, and attenuation, in the polymer melt prior to exiting the extrusion die. A special transducer adapter and wave re ector were incorporated in the design of the extrusion die. The density of PVC foam was varied by varying the blowing agent content in the resin compound prior to extrusion. A mathematical derivation of the behavior of ultrasound waves in the melt is presented and used to calculate the attenuation coefficient of the polymer melt at various foam densities. An empirical relation was derived between the calculated attenuation coefficient of the polymer melt and the measured density of the foam extrudate. This relation can be used to estimate the foam density based on the acoustic measurement of the melt in the extrusion die. Further work is proposed to normalize for the effect of variations in the melt temperature and pressure on the ultrasound measurements.
© 2000, Carl Hanser Verlag, Munich
Articles in the same Issue
- Editorial
- Seventh of a Series: Pioneer of Carbonaceous Pitch Processing Sugio Otani
- Invited Paper
- Injection Blow Molding Technology for Polyethylene Terephthalate
- Screw Extrusion/Mixing
- A New Polymer Processing Technology for Polymer Blends with Unmatched Viscosity: Solid-State Shear Pulverization (S3P)
- In-Line Density Monitoring of Rigid PVC Foam during Extrusion Process
- In-Process R eometry Studies of LDPE Compounds
- In-Process R eometry Studies of LDPE Compounds
- Rheological and Morphological Properties of Immiscible Blends and Microfiber Preparation from the Blends
- Reactive Extrusion
- Development of a Direct Polycondensation Process for Poly (L-lactic acid)
- Fiber and Film
- Radially Dependent Stress and Modeling of Solidi cation in ilament Melt Spinning
- Structure Development in Melt Spinning Syndiotactic Polypropylene and Comparison to Isotactic Polypropylene
- Fibers and Films
- Investigation of Structure and Properties in Biaxially Stretched Poly(butylene terephthalate) Films
- Molding
- Filling and Postfilling Analysis of Injection/Compression Molding
Articles in the same Issue
- Editorial
- Seventh of a Series: Pioneer of Carbonaceous Pitch Processing Sugio Otani
- Invited Paper
- Injection Blow Molding Technology for Polyethylene Terephthalate
- Screw Extrusion/Mixing
- A New Polymer Processing Technology for Polymer Blends with Unmatched Viscosity: Solid-State Shear Pulverization (S3P)
- In-Line Density Monitoring of Rigid PVC Foam during Extrusion Process
- In-Process R eometry Studies of LDPE Compounds
- In-Process R eometry Studies of LDPE Compounds
- Rheological and Morphological Properties of Immiscible Blends and Microfiber Preparation from the Blends
- Reactive Extrusion
- Development of a Direct Polycondensation Process for Poly (L-lactic acid)
- Fiber and Film
- Radially Dependent Stress and Modeling of Solidi cation in ilament Melt Spinning
- Structure Development in Melt Spinning Syndiotactic Polypropylene and Comparison to Isotactic Polypropylene
- Fibers and Films
- Investigation of Structure and Properties in Biaxially Stretched Poly(butylene terephthalate) Films
- Molding
- Filling and Postfilling Analysis of Injection/Compression Molding
