20. - 22. 10. 2009, Roznov pod Radhostem, Czech Republic, EU 1 IN-LINE QUALITY CONTROL OF POLYMER NANOCOMPOSITES USING NEAR-INFRARED SPECTROSCOPY Stephan Laske a , Andreas Witschnig a , Milan Kracalik a , Michael Feuchter b , Gerald Pinter b , Günther Maier c , Günter Rüdiger Langecker a , Clemens Holzer a a IKV – Institute of Plastics Processing, University of Leoben, Franz Josef Strasse 18, 8700 Leoben, Austria b Institute of Materials Science and Testing of Plastics, University of Leoben, Franz Josef Strasse 18, 8700 Leoben, Austria c Material Center Leoben, Roseggerstraße 12, 8700 Leoben, Austria stephan.laske@unileoben.ac.at Abstract Layered silicates as nanoscale fillers have a great potential in improving polymer material properties. Depending on the composite structure (agglomerated, intercalated or exfoliated) a significantly higher level of reinforcement can be achieved with a very small amount of filler. The composite properties are usually characterized by X-ray diffraction (XRD), tensile tests and microscopic methods (e.g. transmission electron microscopy). Apart from the fact that these methods are very time consuming and cost-intensive, they are off-line methods and hence not suitable for industrial use. A new approach is the in-line characterization of nanocomposite quality using Near-Infrared spectroscopy (NIR). The presented results show a direct correlation between the nanocomposite quality determined by XRD and tensile tests and the data analyzed from in-line NIR measurements. Furthermore, NIR technique and chemometric analysis allow real-time, quantitative information about nanocomposite quality during processing. 1. INTRODUCTION Nanocomposites are modified polymers with particles, where at least one dimension is in the order of nanometers. Polymer material reinforced by nanoscale particles exhibit significantly higher performance, for example higher elastic modulus, tensile strength, thermal resistance, lower gas and liquid permeability, reduced flammability and enhanced rheological properties already for small amounts of the filler [1], [2]. For preparation of polymer nanocomposites, layered silicates (clay, especially montmorillonite, MMT) have been the most commonly used nanofillers due to the possibility to achieve aspect ratios ideally up to 1000. According to the dispersion and the homogeneity of the nanofiller conventional composites, intercalated nanocomposites and exfoliated nanocomposites can be formed. To determine the homogeneity of the material a variety of methods are commonly used. These include optical (scanning (SEM) and transmission (TEM) electron microscopy), mechanical (tensile strength, extensional rheology) and light scattering methods (small angle (SAXS) and wide angle (WAXS) x-ray scattering). A new way to determine material homogeneity is the use of near infrared spectroscopy (NIR). NIR-spectroscopy is a non-destructive, optical method to obtain information about the composition of samples and interactions within the sample. Near- and mid-infrared methods (NIR, MIR) measure the absorbance of light due to excitation of molecular vibrations of the substance under investigation. Mid-infrared measurements (often referred to only as IR) are exploiting radiation in a spectral range between 2500 and 25000 nm, detecting fundamental molecular