QUANTITATIVE-ANALYSIS OF LATEX IN PAPER COATINGS BY ATR-FTIR SPECTROSCOPY

Attenuated total reflectance Fourier transform infrared spectrometry (ATR-FTIR) has been used to determine the amount of styrene-butadiene latex on the surface of coated papers and to predict the composition of the polymer. Spectrum recording was performed on the sample in its usual form without any modification. For quantitative analysis, partial least squares (PLS) regression, principal component regression (PCR) and multi-linear regression (MLR) were used to calculate models for prediction. The best result is obtained with PLS. We analysed two series of paper samples. The first analysis concerns the measurement of the quantity of latex of a constant quality on the coating surface. For 15 samples the concentration varied between 5 and 25 parts (grams per 100 g of mineral pigments). We compared the predictive results at various resolutions. We obtained a relative error of 0.15 parts in latex at 4 cm(-1) resolution. The second analysis concerns the measurement of the styrene/butadiene ratio in various types of latex. We obtained a relative error of 0.156 parts for styrene determination and 0.161 parts for butadiene determination.