Triplet‐state quenching by photostabilizers of polyolefins

Paramagnetic nickel(II) complexes which are used as commercial photostabilizers of polyolefins are shown in laser photolysis studies to quench the triplet state of benzophenone in dilute benzene solution. The efficiency of quenching observed is less than that of diamagnetic square‐planar nickel(II) complexes which are more effective photostabilizers of polypropylene in “Xenotest” experiments. The observed rate constants for quenching of triplet benzophenone are compared with those observed by other workers for quenching of singlet oxygen, O2*(1Δg), in dilute solution. The relevance of these studies to the understanding of photodegradation in polyolefins is discussed.