ANALYSIS OF POLYURETHANES USING CORE EXCITATION SPECTROSCOPY .2. INNER-SHELL SPECTRA OF ETHER, UREA AND CARBAMATE MODEL COMPOUNDS

Core excitation spectra of selected small molecule analogue species ha ve been acquired to assist interpretation of the core excitation spect ra of model methylenediphenyldiisocyanate (MDI) polyurethane polymers. Oscillator strength spectra for C 1s and O 1s core excitation of diet hyl ether and diisopropyl ether; C 1s, N 1s, and O 1s core excitation of urea, N-phenyl urea, N,N'-diphenyl urea, ethyl carbamate, N-phenyl carbamate, N-phenyl N-methyl carbamate, and benzyl carbamate have been derived from gas phase electron energy loss spectra (EELS). Extended Huckel Molecular Orbital (EHMO) calculations are used to assist assign ment and to interpret the effect of pi-electron delocalization on the gas phase spectra. Functional group identification by core excitation is explored for the purpose of using core excitation spectra for micro analysis of polyurethane polymers. (C) 1995 John Wiley & Sons, Inc.