New organic PVC photo-stabilizers derived from synthesised novel coumarine moieties

Abstract

New four coumarin derivatives (9–12) compounds have been successfully synthesized from the reaction of salicyaldehyde and ethylacetoacetate yielding 3-acetyl coumarine, which on further treatment with bromine/chloroform gave 3-(2-Bromoacetyl) coumarine. Substituted 4-(Benzylidene-amino)-]triazole-3-thiol reacted with 3-(2-Bromoacetyl) coumarine to give 3-sulfanyl-acetyl-4-(Benzylidene-amino)-triazol related coumarin derivatives. The newly synthesized products were characterized with FTIR,1H and13C NMR, and energy dispersive X-ray spectra to confirm their chemical structures. All above used techniques demonstrated the formation of target products with high percentage of purity. The synthesised compounds (9–12) have been investigated as organic additives to protect poly(vinyl chloride) (PVC) from photo-degradation at (λmax = 313 nm) and irradiation period 300 h in the atmosphere. The stabilizing efficiencies of blended PVC films were examined by detecting changes in their infrared spectra, weight, and average molecular weight viscosity. A light microscope, atomic force microscopy, and a scanning electron micrograph were all used to examine the surface morphology of the films. The additives enhanced considerable resistance of films against irradiation and the polymeric surface was significantly smoother in the presence of the coumarine derivatives compared with the blank film. The strongest photo-stabilization effect was seen in coumarine derivative (12) containing 2-hydroxy naphthol the most effective as UV absorber, free radical scavenger, and quencher. This phenomenon appears to allow energy to be transported through resonant aryl rings and various intersystem crossover mechanisms.