LONG-TERM RADIATION-INDUCED EFFECTS ON SOLID STATE CHITOSAN

Treatment of chitosan with ionising radiation is one of the methods by which it is modified for various applications. However, in the case of chitosan irradiated in the solid state, the radicals formed during irradiation can be stabilised in its crystalline phase and subsequently cause post-irradiation changes. It has been observed that further degradation of the polymer occurs during storage of the irradiated polymer, resulting in an increase in oxidation products and a decrease in deacetylation degree. This effect results from the transformation of radicals leading to the formation of stable nitroxyl radicals, a process observed years after irradiation.

Characterisation of the electronic structure of some stable nitroxyl radicals using variable energy photoelectron spectroscopy

Core and valence ionizations of three stable nitroxyl radicals studied using synchrotron radiation reveal strong intramolecular interactions in amide derivatives.