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Bull. Spec. CORESTA Congress, Jerez de la Frontera, 1992, p. 194, T8, ISSN.0525-6240

Qualitative analysis of adhesives using FTIR spectroscopy

LEWIS W.H.; PARRISH; ALLRED; LEYDEN; HARWARD
Philip Morris USA, Richmond, VA, USA
A method was developed for the qualitative FTIR spectroscopic analysis of adhesive. The method allows for the collection of spectra from both neat and headspace samples. An attenuated total reflectance (ATR) crystal is used to obtain the spectrum of the neat sample. The ATR spectrum provides the information necessary to type or classify a particular adhesive. The presence of volatile organic components in an adhesive is determined qualitatively by obtaining an FTIR gas phase spectrum of the headspace sample. The headspace sample is generated using a microvave oven to heat the adhesive in a digestion vessel. The organic volatiles are subsquently introduced into an evacuated gas cell via direct injection. The gas phase spectra are used to screen for the presence of"gross contaminants". For the ATR and headspace sample analysis, spectra of unknown adhesives are compared to training sets consisting of spectra for known"acceptable"adhesives. The spectra in the training sets determine the range of variation allowed for an unknown that is to be classified by the training group. The integration of several software packages has resulted in a simple, automated procedure that requires less than 15 minutes for each adhesive analysis. The method has been tested in our laboratory with limited samples and is now being field tested.