QUANTITATIVE-DETERMINATION OF POLYMER AND MINERAL-CONTENT IN PAPER COATINGS BY INFRARED-SPECTROSCOPY - IMPROVEMENTS BY NONLINEAR TREATMENTS

The quality of a printed image on coated papers, to a great extent, de pends on the coating surface properties (nature of the components, rel ative abundance and so on). The potential of infrared spectroscopy as a rapid analytical technique for the quantitative analysis of the coat ing is demonstrated. Experimentally, spectra are recorded by Attenuate d total reflectance (ATR) with Fourier transform infrared spectroscopy , Partial least squares (PLS) regression is used as the multivariate l inear calibration method for predicting calcium carbonate, styrene and butadiene in the coatings. The effect of non-linear treatments is est ablished by the improvements which occurred after the multiplicative s catter correction or the application of an artificial neural network o n the PLS scores, especially near the concentration limits of each com pound.