Characterisation of chitosan and chitosan-based materials by temperature programmed desorption mass spectrometry

The thermal behaviour of chitin, chitosan, and their derivatives is of great importance both for practical applications and for understanding the processes of interaction with additional compounds comprising chitosan-based materials. In this work, the samples of chitin and chitosan obtained in our laboratory from various sources (insects, mushrooms) and commercial samples, as well as derivatives containing iodine, fucorcinum, methylene blue, neomycin, etc., were studied with temperature programmed desorption mass spectrometry. The method reveals the differences in the dehydration of samples. Thermal decomposition in the temperature range from 150 to 200°C is associated with decarboxylation, and above 200°C with decomposition of the main chain. The thermal behaviour of samples depends on the origin of chitin, i.e., the fungal chitin starts to decompose at a lower temperature than insect chitin. The latter one shows thermal behaviour comparable to that of chitin from crustaceans. Chitosan obtained from chitin of various origins is more uniform. The additives in the derivative materials influence the thermal behaviour in different ways, especially a substantial difference was seen in the case of iodine combined with fucorcinum