Effect of some biologically active pyridopyrimidine derivatives on photostability and bioactivity of rigid poly(vinyl chloride)

Some pyridopyrimidine derivatives with high biological activity have been investigated as photostabilizers for rigid Poly(vinyl chloride) (PVC). Their stabilizing efficiencies were evaluated by determining the percentage of weight loss, the amount of formed gel, as well as the intrinsic viscosities, of the photodegraded PVC. The extent of discoloration of the photodegraded polymer was also evaluated. The antimicrobial activities of PVC was evaluated in absence and in presence of the investigated materials. The applied materials reduced the loss in weight that resulted from HCl evolution during photodegradation. Both viscosity and gel content measurements showed also a decrease in their values during the degradation process. The extent of discoloration was also improved. The results have proved a greater stabilizing efficiencies of the antimicrobial pyridopyrimidine derivatives than that of the industrial UV absorber, phenyl salicylate. Photostabilized samples of PVC exhibited good antimicrobial activities against some types of bacteria and fungi. A radical mechanism was proposed to account for the stabilizing action of the investigated products. J. VINYL ADDIT. TECHNOL., 24:208-216, 2018. (c) 2016 Society of Plastics Engineers