Analysis of Polymer Pellets Obtained from Two Extruders Using near Infrared Spectroscopy

The near infrared spectroscopic determination of additive levels in polypropylene pellets obtained from two process extruders/pelletisers is described. A quotient-term multiple linear least-squares spectroscopic model was derived that characterises analyte concentration and corrects for spectroscopic differences within the matrix due to the extruder/pelletisers. The analytical error of the spectroscopic model is comparable to the reference method used to derive the spectroscopic model.