Correlations of attenuated total reflectance spectra to physical properties or polyurethane foams

Polyurerhane foams are produced from five basic components: polyol, silicone surfactant, tin and amine catalyst, water and an isocyanate. Inconsistency in the measurement of physical properties of the foam arises if there is a change in reactivity of any of the components. The change in reactivity is often the result of batch-to-batch variability of the chemical components. Production of a consistent foam in these cases is difficult and manufacturing takes time and wastes chemicals. The purpose of this study is to correlate attenuated total reflectance (ATR) infrared spectra of the physical properties of the foam. Correlations were made with the use of partial least squares (PLS) software. Both PLS-1 and PLS-2 algorithms were implemented for correlation. The correlation coefficient (R-2) was better with the PLS-1 than the PLS-2 algorithm. The values predicted by the PLS model fall within the standard deviation.