Abstract: Disclosed is a method of preparing a rare-earth alkyl phosphate solution, the method including step (a) of preparing an alkyl phosphate amine salt solution by reacting an organic amine with an alkyl phosphate in a first solvent; step (b) of preparing a rare-earth metal salt solution by reacting a rare-earth metal oxide with an acid in the second solvent; and step (c) of mixing and reacting the alkyl phosphate amine salt solution with the rare-earth metal salt solution.

Abstract: The polymeric composition comprising (A) a polyester resin and (B) micrometrical silica particles, preferably particles made of cristobalite or quartz, dispersed in the polyester resin preferably at concentration of at least 2 wt %. The polyester resin preferably comprises a PET homo or copolymer. Packaging articles, especially biaxially stretched blow molded containers, made with the said polymeric composition exhibit high opacity to UV and visible light radiations as well as improved barrier properties to O2 and to water vapor, and improved thermal and mechanical properties.