Photochemical Behavior of Multicomponent Polymeric-based Materials by Dan Rosu & Visakh P. M

Author:Dan Rosu & Visakh P. M.
Language: eng
Format: epub
Publisher: Springer International Publishing, Cham

Many studies carried out on polyethylene/nanoclay systems [68–70] showed that the polymer as the major component of nanocomposites degrades faster than the pristine material, when it is exposed to UV radiation. This feature was explained on the basis of interaction of organo-clays and the antioxidant used for the protection of polymer substrate. Morlat-Therias et al. observed in the study on the photochemical stabilization of LLDPE/clay nanocomposites by infrared spectroscopy [71] that the presence of organo-clay promotes a lower durability of the nanocomposites exposed to artificial or natural UV light. By the comparison of the effectiveness provided by various UV absorbers (Cyasorb UV-1164, Cyasorb UV-2337, Cytec THT 6460) and by a metal deactivator compound (i.e. Irganox MD-1024), it was observed that the use of metal deactivator is an efficient solution for the stabilization of nanocomposite. In the presence of the metal deactivator, the active metal ions are scavenged by chelation forming an inactive complex [71].

Various compounds such as thiobisphenol were reported to exhibit a pro-oxidant effect in the early period of polyethylene photooxidation, which is accelerated as their concentration is enhanced, while on the later irradiation period the carbonyl build up was retarded [72]. The retardation of the carbonyl accumulation was obtained with a compound based on dodecyl-3,3′-thiodipropionate over the whole period of ultraviolet exposure. Kinetic data showed [72] that the concentration of 0.1 w/w% of thiobisphenols determines the most effective retardation for the accumulation of carbonyl group in LDPE films.

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