Photodegradation of acrylic resins used in the conservation of stone

The photodegradative behaviour of a series of films of acrylic resins, under controlled conditions (RH=50% and T=25°C) has been studied. Films of acrylic resins were applied both on a dolomitic white marble support and on potassium bromide disks. The chemical evolution of the system has been followed by means of FT–IR spectra, HPLC–SEC, colour and water absorption measurements. The main degradation pathway under ultraviolet irradiation is chain scission. The observed rates of photodegradation of the different resins may be related to the type of the ester group and to the presence of the α-methyl group in the main chain.

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