CHARACTERIZATION OF CHITOSAN BY PYROLYSIS MASS-SPECTROMETRY, THERMAL-ANALYSIS AND DIFFERENTIAL SCANNING CALORIMETRY

The thermal behaviour of chitosans with various degrees of deacetylation has been studied. The differential scanning calorimetry curves of the samples exhibit two peaks. The first, due to the loss of reticular water, is endothermic, with a peak temperature of 100-degrees-C, whereas the second is exothermic, with a maximum at 310-degrees-C, and is associated mainly with the first decomposition stage of the polysaccharide. It was found that the amount of energy liberated at this temperature increases as the deacetylation degree increases. Pyrolysis-mass spectra of chitosan samples with different degrees of deacetylation indicated that the peak (m/z) ratios 94:125, 80:125 and 80:110 increase as the degree of deacetylation increases, so that they may be used in the characterization of these polysaccharides in addition to the peak ratios 80:60, 67:60 and 80:42 already proposed.