Studies of the Photocycloaddition of Benzophenone to cis-Polyisoprene

Ng, Howard C.; Guillet, J. E.

doi:10.1021/ma60058a030

Cited by 13 publications

(6 citation statements)

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“…Further evidence for this suggestion has been maintained both by recent studies in our own laboratories (Ref . 3) and in those of Professor Geuskens in Brussels (Ref .…”

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confidence: 97%

Studies of the mechanism of polyolefin photodegradation

Guillet¹

1980

Pure and Applied Chemistry

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-Through studies of the photodegradation of commercial polymers and their model compounds, the roles of ketone carbonyl and hydroperoxide functional groups in the overall photodegradation mechanism have been elucidated. Besides undergoing photochemical reaction themselves, polymeric ketones are capable of sensitizing the decomposition of the more reactive hydroperoxide functionality by energy transfer involving an exciplex intermediate.It Is now well established that the primary mechanism of photodegradation of hydrocarbon polymers when exposed to terrestrial UV involves the process of photooxidation. Although there has been much controversy in recent years about the relative roles of different absorbing groups in polyolefins, it seems clear that in most cases initiation of the photooxidation process is caused primarily by absorption of light by only two groups, namely the hydroperoxide group and the ketone carbonyl. The relative importance of these two groups in the photooxidation process may vary significantly depending on the structure of the particular polyolefin. In polyethylene, for example, it is well known that the steady state concentration of hydroperoxides during a photooxidation in the solid phase remains very low, while in polypropylene, substantial concentrations of hydroperoxide are produced and maintained in the photostationary state primarily because they exist in a sequential hydrogen bonded form. These hydrogen-bonded peroxides may be significantly more stable to UV photodecomposition than an isolated hydroperoxide group.In polyethylene, careful studies of photooxidation rates under constant UV irradiation in the solid phase indicate that the process follows an exponential relationship, as shown in Fig. 1. Since under

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“…Further evidence for this suggestion has been maintained both by recent studies in our own laboratories (Ref . 3) and in those of Professor Geuskens in Brussels (Ref .…”

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confidence: 97%

Studies of the mechanism of polyolefin photodegradation

Guillet¹

1980

Pure and Applied Chemistry

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“…Figure6. Evolution of the IR spectra of a polystyrene film (thickness 105 µ ) photooxidized for 221 h (B) and then photolyzed (X > 300 nm) for (C) 199 h, (D) 367 h, (E) 531 h, (F) 739 h, and (G) 950 h. Spectrum A is the initial spectrum.…”

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confidence: 99%

Polystyrene photooxidation. 1. Identification of the IR-absorbing photoproducts formed at short and long wavelengths

Mailhot¹,

Gardette²

1992

Macromolecules

110

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“…Such a reaction may be visualized as a novel type of photopolymerization, in which a photon is absorbed for the creation of each ring in the polymer backbone. Guillet has proposed the name "photoreplica polymerization" for such reactions, in which a preformed polymer chain serves as a substrate for photochemical cycloaddition (6).…”

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confidence: 99%