Photochemical stability and photostabilizing efficiency of poly(methyl methacrylate) based on 2-(6-methoxynaphthalen-2-yl)propanoate metal ion complexes

The photostabilization of poly(methyl methacrylate) (PMMA) films having 2-(6-methoxynaphthalen-2-yl)propanoate and Sn(II), Ni(II), Zn(II) and Cu(II) complexes was investigated. The production of PMMA films containing such complexes (0.5% by weight) was carried out by the casting method using chloroform. The photostabilization activities of the compounds were determined by monitoring the hydroxyl index with irradiation time. The quantum yield of the chain scission (Φcs) for the complexes in PMMA films and the changes in the viscosity average molecular weight of PMMA with irradiation time were evaluated. The rate of photostabilization for PMMA in the presence of the additives was found to follow the order NiL2 > CuL2 > ZnL2 > SnL2 (L, ligand). Depending on the structure of the additive, such as a peroxide decomposer, UV absorption or a radical scavenger for the photostabilizer, several mechanisms are suggested.