Enhanced photostability of PVC using benzenesulfonamide derivatives

This study investigated the effect of Schiff bases photostabilizers from benzenesulfonamide on PVC films. Benzenesulfonamide derivatives (1-5) were prepared by reacting 4-aminobenzenesulfonamide with five substituted benzaldehyde, the structural properties of all compounds were confirmed by 1HNMR. These compounds were incorporated into the composition of polyvinyl chloride (PVC) membranes at a weight concentration of 0.5%. The optical stability of PVC was studied by several techniques including finding the photodegradation constant of PVC as well as weight loss and scanning electron microscopy (SEM) of the polymer films. The photodegradation rate constants (kd) of the modified PVC films, which included these Schiff bases, decreased significantly (3 × 10-4 sec-1 to 39 × 10-4 sec-1) compared to the control PVC films (88 × 10-4 sec-1). Benzenesulfonamide derivative 5 showed the strongest photostabilizing activity. Irradiated films containing benzenesulfonamide compounds (1-5) showed a weight loss of 35%. Scanning electron microscopy (SEM) of the additive-treated PVC after 250 h of irradiation showed a heterogeneous surface morphology resembling broken rocks, indicating the structural changes induced by radiation. These results demonstrate the effectiveness of benzenesulfonamide derivatives as photostabilizers for PVC.