Photostabilizing Efficiency of Poly(vinyl chloride) in the Presence of Organotin(IV) Complexes as Photostabilizers

Three organotin complexes containing furosemide as a ligand (L), Ph(3)SnL, Me(2)SnL(2) and Bu(2)SnL(2), were synthesized and characterized. Octahedral geometry was proposed for the Me(2)SnL(2) and Bu(2)SnL(2), while the Ph(3)SnL complex has trigonal bipyramid geometry. The synthesized organotin complexes (0.5% by weight) were used as additives to improve the photostability of poly(vinyl chloride), PVC, (40 μm thickness) upon irradiation. The changes imposed on functional groups, weight loss and viscosity average molecular weight of PVC films were monitored. The experimental results show that the rate of photodegradation was reduced in the presence of the organotin additives. The quantum yield of the chain scission was found to be low (9.8 × 10(−7)) when Ph(3)SnL was used as a PVC photostabilizer compared to controlled PVC (5.18 × 10(−6)). In addition, the atomic force microscope images for the PVC films containing Ph(3)SnL(2) after irradiation shows a smooth surface compared to the controlled films. The rate of PVC photostabilization was found to be highest for Ph(3)SnL followed by Bu(2)SnL(2) and Me(2)SnL(2). It has been suggested that the organotin complexes could act as hydrogen chloride scavengers, ultraviolet absorbers, peroxide decomposers and/or radical scavengers.