Photooxidation of polystyrene-the role of impurities as prodegradants

The role of in‐chain peroxides and phenyl alkyl ketone end groups in the initiation of photooxidation of polystyrene is discussed. Using quantitative phosphorescence spectroscopy and viscometric methods, the photolysis and thermolysis of small amounts of in‐chain peroxides present in polystyrene prepared under different oxygen concentrations was investigated. It was shown that in‐chain peroxides are unlikely initiators of photooxidation in polystyrene prepared in high‐temperature commercial syntheses, but will act as the precursor of the photoinitiator, the phenyl alkyl ketone end group.