An In-line Melt Rheometer for Molten Plastics
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B. I. Nelson
Abstract
An in-line rheometer designed for use as a sensor for closed-loop control of melt processing operations has been previously described. This instrument can measure the true viscosity of a melt stream over a range of shear rates. In order to evaluate its performance in processing applications the rheometer was mounted on a twin-screw extruder. A chemical degradation process was used to introduce changes in the molecular weight distribution, and thus the viscosity of a polypropylene resin, and these changes were monitored using the rheometer. For rapid replacement of melt in the zone of controlled shear in the rheometer, flow simulations indicated that it would be advantageous to operate the rheometer in a cyclic mode. A stochastic process identification technique based on a pseudorandom binary signal was used to determine the parameters of a first-order plus deadtime model of the process. In order to estimate the portion of the system response due to rheometer dynamics, residence time distributions were measured both with and without the rheometer present. It was found that the rheometer has a dead time of about 6's and a first order time constant of less than 15 s. The response of the new instrument is thus significantly faster than than that of melt process rheometers now commercially available.
© 1994, Carl Hanser Verlag, Munich
Artikel in diesem Heft
- Contents
- Contents
- Editorial
- Tenth in a Series: Fried. Krupp: Pioneer Integrated Steel and Processing Machinery Manufacturer. Part 1. Essen, Magdeburg and Harburg (1812–1960)
- Internal Mixers
- Finite Element Modelling of Non-isothermal Viscometric Flows in Rubber Mixing
- Screw Extrusion and Mixing
- The Optimisation of Masterbatch Formulations for Use in Single Screw Machines
- Morphological Changes of a Polymer Blend into a Twin-Screw Extruder
- An In-line Melt Rheometer for Molten Plastics
- Selecting Continuous Compounding Equipment Based on Process Considerations
- Reactive Processing
- Peroxide Induced and Thermal Degradation of Polypropylene
- Reactive Blending of Polyamide 6 and Polycarbonate
- Modification of Polypropylene by Maleic Anhydride
- Fibers and Films
- Melt Strength Behaviour of Polypropylenes
- Molding
- Multilayer Injection Moulding
- Miscibility and Mechanical Properties of Poly(ether imide)/Liquid Crystalline Poly(ester imide) Blends
- The Effects of Recycling and Degradation on Parison Extrusion
- Modeling and Simulation of High Reynolds' Number Flows During Reaction Injection Mold Filling
Artikel in diesem Heft
- Contents
- Contents
- Editorial
- Tenth in a Series: Fried. Krupp: Pioneer Integrated Steel and Processing Machinery Manufacturer. Part 1. Essen, Magdeburg and Harburg (1812–1960)
- Internal Mixers
- Finite Element Modelling of Non-isothermal Viscometric Flows in Rubber Mixing
- Screw Extrusion and Mixing
- The Optimisation of Masterbatch Formulations for Use in Single Screw Machines
- Morphological Changes of a Polymer Blend into a Twin-Screw Extruder
- An In-line Melt Rheometer for Molten Plastics
- Selecting Continuous Compounding Equipment Based on Process Considerations
- Reactive Processing
- Peroxide Induced and Thermal Degradation of Polypropylene
- Reactive Blending of Polyamide 6 and Polycarbonate
- Modification of Polypropylene by Maleic Anhydride
- Fibers and Films
- Melt Strength Behaviour of Polypropylenes
- Molding
- Multilayer Injection Moulding
- Miscibility and Mechanical Properties of Poly(ether imide)/Liquid Crystalline Poly(ester imide) Blends
- The Effects of Recycling and Degradation on Parison Extrusion
- Modeling and Simulation of High Reynolds' Number Flows During Reaction Injection Mold Filling
