Photo-oxidation of polymers—VIII. The photo-oxidation of polystyrene containing aromatic ketones

Metal‐Catalyzed, Photo‐Assisted Selective Transformation of Tertiary Alkylbenzenes and Polystyrenes into Carbonyl Compounds

“…Several experiments have indicated the involvement of benzyl radicals in the partial or non‐selective degradation of PS [19c–e,20a,28] . In our case, a very faint electron paramagnetic resonance (EPR) signal was detected, although it could have been due to the use of PEG‐400 as reaction media.…”

“…suggested that acetophenone end‐groups present in commercially available PS were responsible not only for the yellowing and embrittlement after long‐term exposure to sunlight but also for the quicker photodegradation of PS under UV light (310 and 365 nm) leading to complex mixtures. They evaluated the accelerating effect of adding several aromatic ketones such as benzophenone and acetophenone, concluding that these ketones initiated the above photooxidation [19a,d,30] …”

Photodegradation of Polystyrene Films Containing UV-Visible Sensitizers

“…According to Geuskens et al [13] polymers with excited unsaturated end groups will decompose by a molecular mechanism to yield conjugated dienes and hydrogen (Figure 7) [32]. Figure 8 shows the evolution of the absorption at 312 nm (assigned to conjugated double bonds) during the photodegradation of polystyrene sensitized by benzophenone.…”

“…BP was first studied as a photodegradation additive in polystyrene by Geuskens [13]. When BP absorbs light it will be excited to an upper singlet state, which subsequently decays to the triplet state.…”

Testing Methods of Weathered Specimen

“…Photodegradation mechanisms of polystyrene [139][140][141][142][143][144][145][146][147][148][149][150] and polycarbonate [142][143][144] were also studied by IR, generally by carbonyl and hydroperoxide formation. Studies have also been done to evaluate the effect of UV radiation wavelength on the rate of the photolytic process.…”