C-13 SOLID-STATE NUCLEAR-MAGNETIC-RESONANCE AND FOURIER-TRANSFORM INFRARED STUDIES OF THE THERMAL-DECOMPOSITION OF CORK

The thermal decomposition of cork has been studied by Fourier transfor m infrared (FTIR) spectroscopy and C-13 solid-state nuclear magnetic r esonance (NMR) spectroscopy with cross-polarization and magic-angle sp inning (CP-MAS), high-power H-1 decoupling (HPDEC) and cross-polarizat ion depolarization-polarization (CPDP). Waxes and other soluble compon ents of cork begin to decompose at ca. 150 degrees C. This is accompan ied by partial decomposition of suberin, probably initiated at the poi nts of attachment to the cell wall. The carbohydrates begin to decompo se at ca. 200 degrees C. The decomposition of linin begins at 250-300 degrees C, while suberin undergoes further degradation. Significant am ounts of coke are formed in the process. At 400 degrees C cork has bee n transformed into coke with traces of partially decomposed suberin. T he thermal decomposition of cork is dependent on the calcination time partly in the 200-350 degrees C range.