Synthesis, characterization, properties, and use of new fusidate organotin complexes as additives to inhibit poly(vinyl chloride) photodegradation

Poly(vinyl chloride) (PVC) is a common plastic that has many uses. Additives enhance the properties of PVC and enable its use in specific applications under harsh conditions. Therefore, several new tin complexes containing the fusidate unit were synthesized and tested as PVC photostabilizers. The reaction of sodium fusidate and appropriate tin chloride or oxide in boiling methanol provides the corresponding organotin complex in high yield. The structures and properties of the synthesized tin complexes were established using several analytical and spectroscopic tools. Also, the surface morphology of the complexes was inspected using various methods. The fusidate unit acts as either a monodentate (triphenyl and dibutoxide derivatives) or bidentate (dimethyl and dibutyl derivatives) ligand depending on the substitutes attached to the tin atom. The PVC was blended with tin complexes (0.5% by weight), and thin films were made and irradiated with ultraviolet (UV) light for a long time. The effect of tin complexes on PVC as photostabilizers was assessed using different methods. The tin complexes significantly reduce PVC photodegradation. The non-desirable changes in the irradiated PVC were minimal in the presence of additives compared to those observed in the blank film. The dimethyltin derivative, which had the highest surface area compared to the other complexes, was the most efficient additive to decrease the photodegradation of PVC film after irradiation. The tin complexes prevent photodegradation by acting as ultraviolet absorbers as well as scavengers for hydrogen chloride and peroxides.