Over the last decade, there has been an increased drive in the polymer industry toward the development of in-line monitoring techniques for analysis of melt processing. Manufacture of high material volumes combined with stringent quality-control restrictions and the requirement for tailored end-user products, have made the implementation of analytical methods essential for measurement of material characteristics. This paper presents the application of a range of spectroscopic techniques for in-line analysis of polymer extrusion processes. Fourier transform near-infrared (FT-NIR), Raman and fluorescence spectroscopy have been successfully implemented as tools to monitor a range of processing characteristics including copolymer melt and additive composition, material residence time distribution and degree of polymerization. In combination with partial least squares (PLS) chemometric analysis, these spectroscopic techniques are demonstrated to be sensitive and robust tools for monitoring a wide range of chemical and physical parameters at high-temperature and pressure in a polymer-processing environment.
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