Polymers, Vol. 7, Pages 2190-2204: Viscoelastic, Spectroscopic and Microscopic Study of the Photo Irradiation Effect on the Stability of PVC in the Presence of Sulfamethoxazole Schiff’s Bases

The photostabilization of poly(vinyl chloride) (PVC) films having five Schiff's basesderived from sulphamethoxazole has been investigated. The casting method was used toproduce PVC films containing sulphamethoxazoles (0.5% by weight), in tetrahydrofuran. Thephotostabilization activities of five additives were determined by monitoring the hydroxyl, polyeneand carbonyl indices with irradiation time. In addition, the quantum yield of the chain scission(Fcs) and the changes in viscosity average molecular weight of PVC films containing Schiff's basseswere evaluated with irradiation time. The rate of photostabilization for PVC films in the presenceof five Schiff's base additives was found to be the highest in the case of 2-hydroxybenzylidenederivative and the lowest in the unsubstituted benzylidene derivative. Several mechanisms havebeen suggested to explain the photostabilization of PVC in the presence of Schiff's bases that mainlyact as UV absorbers and radical scavengers for photostabilizers.

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