Complex formation in photostabilized polypropylene

Abstract The formation of a yellow complex between 2-hydroxy-4-octoxybenzophenone and calcium stearate in the matrix of polypropylene has been observed. The same complex was prepared in model conditions and mixed into the polymer. In order to prevent colour changes in polypropylene, aliphatic or aromatic carboxylic acids were used as ‘harder’ ligands. The photooxidative stability of polymer films was evaluated.