Photodegradation of cellulose nitrate

Cellulose nitrate films were photolytically degraded in air and in vacuum. Crosslinking reactions took place during the early stages of the irradiation in the presence of air, with the formation of a new chromophoric system which absorbed light at 280 nm. It is evident that oxygen is necessary to effect crosslinking, and the nitrate group also appears to participate in this reaction. Denitration occurred during the process of photoirradiation. Further irradiation led to significant degradation of the crosslinked structures as well as chain scission, restructuring, yellowing and a catastrophic loss in mechanical properties. Carbonyl and aldehyde groups were formed as major products.