Vibrational spectroscopic and ultrasound analysis for in-process characterization of high-density polyethylene/polypropylene blends during melt extrusion

Barnes, S. E., Brown, E. C., Sibley, M. G. , Edwards, H. G. M., Scowen, I. J. and Coates, P. D. (2005) Vibrational spectroscopic and ultrasound analysis for in-process characterization of high-density polyethylene/polypropylene blends during melt extrusion. Applied Spectroscopy, 59 (5). pp. 611-619. ISSN 0003-7028

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Spectroscopic techniques such as Raman, mid-infrared (MIR), and near-infrared (NIR) have become indispensable analytical tools for rapid chemical quality control and process monitoring. This paper presents the application of in-line Fourier transform near-infrared (FT-NIR) spectroscopy, Raman spectroscopy, and ultrasound transit time measurements for in-line monitoring of the composition of a series of high-density polyethylene (HDPE)/polypropylene (PP) blends during single-screw extrusion. Melt composition was determined by employing univariate analysis of the ultrasound transit time data and partial least squares (PLS) multivariate analysis of the data from both spectroscopic techniques. Each analytical technique was determined to be highly sensitive to changes in melt composition, allowing accurate prediction of blend content to within ±1 w/w (1�) during monitoring under fixed extrusion conditions. FT-NIR was determined to be the most sensitive of the three techniques to changes in melt composition. A four-factor PLS model of the NIR blend spectra allowed determination of melt content with a standard prediction error of ±0.30 w/w (1�). However, the NIR transmission probes employed for analysis were invasive into the melt stream, whereas the single probes adopted for Raman and ultrasound analysis were noninvasive, making these two techniques more versatile. All three measurement techniques were robust to the high temperatures and pressures experienced during melt extrusion, demonstrating each system's suitability for process monitoring and control. © 2005 Society for Applied Spectroscopy.

Keywords:Error analysis, Extrusion, Infrared spectroscopy, Polyethylenes, Polymer blends, Process control, Raman spectroscopy, Spectroscopic analysis, Ultrasonics, In-line monitoring, Near-infrared region, Process monitoring, Raman, Polypropylenes, polyethylene, polypropylene, algorithm, article, chemistry, combinatorial chemistry, echography, evaluation, materials, materials testing, methodology, online system, Raman spectrometry, system analysis, transition temperature, vibration, Algorithms, Combinatorial Chemistry Techniques, Manufactured Materials, Online Systems, Polyethylene, Polypropylenes, Spectroscopy, Fourier Transform Infrared, Spectrum Analysis, Raman, Systems Integration, Ultrasonography, Vibration
Subjects:F Physical Sciences > F100 Chemistry
Divisions:College of Science > School of Chemistry
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ID Code:13051
Deposited On:19 Mar 2014 17:39

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