IR spectroscopy as a quantitative and predictive analysis method of phenol-formaldehyde resol resins

A set of resin samples was characterized by IR and 13C‐NMR spectroscopy. The suitability of IR spectroscopy for the quantitative analysis of resins was evaluated by statistical methods using the NMR reference data as calibration. The values of interesting properties, for example, the amount of free phenol and the formaldehyde‐to‐phenol (F/P) molar ratio, of the resins being similar to the calibration resins were predicted from the IR spectra. Also, the predicted results were compared with the ones observed by 13C‐NMR spectroscopy. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 2175–2185, 1998