On-line monitoring of molecular weight using NIR spectroscopy in reactive extrusion process

Near infrared spectroscopy (NIR) is a versatile tool for process control, scientific research and quality management. Consequently it is our aim to utilize NIR technique for the understanding and following of reactive extrusion processes. As preliminary results it was shown the molecular weight of degraded, non-purified polyester can be measured and forecasted using purely NIR spectra analysis. In this paper we describe the close correlation of the received molecular weight values of partly glycolised Polyethylene terephthalate (PET) samples using reactive extrusion, measured using size exclusion chromatography (SEC) techniques and chemometric models basing on NIR measurements.