New photostabilizers for PVC based on some diorganotin(IV) complexes

The photostabilization of polyvinyl chloride (PVC) films by diorganotin(IV) complexes of the type Ph2SnL2, Bu2SnL2 and Me2SnL2 of the ligand benzamidoacetic acid complexes was investigated. The PVC films containing concentration of complexes 0.5% by weight were produced by the same casting method from tetrahydrofuran (THF) solvent. The photostabilization activities of these compounds were determined by monitoring the carbonyl, polyene and hydroxyl indices with irradiation time. The changes in viscosity average molecular weight of PVC with irradiation time were also tracked (using THF as a solvent). The quantum yield of the chain scission (Φcs) of these complexes in PVC films was evaluated and found to range between 4.65 × 10−8 and 6.21 × 10−8. Results obtained showed that the rate of photostabilization of PVC in the presence of the additive follows the trend:Ph2SnL2>Bu2SnL2>Me2SnL2According to the experimental results obtained, several mechanisms were suggested depending on the structure of the additive. Among them HCl scavenging, UV absorption, peroxide decomposer and radical scavenger for photostabilizer additives mechanisms.