APPLICATION OF AN AUTOMATED INTERPRETATION SYSTEM FOR INFRARED-SPECTRA .2. CHARACTERIZATION OF AROMATIC SULFONE COPOLYMERS

Univariate and multivariate calibration methods are used for quantitative analysis of aryl ether sulphone-aryl ether ether sulphone copolymers. Calibration data are obtained using transmission, diffuse reflectance and attenuated total reflectance infrared spectrometry. Kubelka-Munk transformations, second-order derivative functions and multiplicative scatter corrections are applied as preprocessing methods. Calibration methods, sampling techniques and preprocessing methods are compared with respect to the prediction error of the hydroquinone (-O-PHI-O-) fraction in the samples. A minimum error (0.003) is obtained by applying partial least squares regression on the second-order derivative of muitiplicative scatter corrected diffuse reflectance spectra.