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Ultrasonics for on-line process monitoring probes polymer properties instead of process parameters alone.
PREFATORY NOTE
Measurements and sensor development for monitoring polymer processing was the subject of the New Technology Forum at the 1998 ANTEC meeting in Atlanta. The objective of the Forum was to highlight the state of the art in realtime measurement methods to characterize the polymer resin as it is undergoing work by the processing machine. Real-time observations yield important information that help the processor to understand the process, to construct mathematical models of the process, to control and optimize the process, and to improve product quality and productivity. Often, knowledge about a process is obtained through indirect observations during post processing quality control, but this has the limitation that it cannot yield information about the direct interaction between resin and machine. Also, it is not possible to use post processing measurements to control a process and to maintain optimum process conditions.
Papers at the 1998 New Technology Forum covered a broad range of measurement methods that involved sensors for measuring rheology, morphology, dielectric properties, birefringence, molecular orientation, crystallinity, crystallization kinetics, modulus, and infrared and Raman spectroscopy. These measurements were made using a variety of different sensors: rheological dies, ultrasonics, optical fibers, in-line microscopes and light scattering devices, and an innovative in-line dielectric ring sensor. One of the themes of the Forum was that each sensor has its advantages and disadvantages. Using a combination of sensors, it is possible to obtain complementary data from each sensor that yield a more complete picture of the process.
The speakers and the titles of their talks were:
"On-Line Rheological Measurements" by John Dealy of McGill University;
"Ultrasonic Probe for On-Line Process Monitoring" by Luc Piche of NRC, Canada;
"Dielectric Measurements for In-Line Monitoring of Polymer Processing" by Michael McBrearty of Chemical ElectroPhysics Inc.;
"Optical Microscope, Light Scattering and Fluorescence Measurements During Polymer Processing" by Eric Amis of the National Institute of Standards and Technology;
"Optical Monitoring Techniques To Follow Rapid Structural Changes During Processing of Polymers" by Miko Cakmak of the University of Akron; and
"Intelligent Materials Processing Application to Polymer Composites" by John Maguire of the Southwest Research Institute.
The following paper, by Luc Piche et al. of the National Research Council...