Photo-oxidation of polymers—III

David, Christiane; Baeyens‐Volant, Danielle; Delaunois, G.; Vinh, Q. Lu; Piret, W.; Geuskens, Georges

doi:10.1016/0014-3057(78)90037-x

Cited by 50 publications

(14 citation statements)

References 8 publications

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“…The shift in the excimer fluorescence band of the irradiated PMS film is in good agreement with that reported with irradiated PS [14] and poly (4-methoxystyrene) [11]. Tovborg and Kops [43] pointed out that quenching of polymeric emission might be attributed to the energy transportation of the oxides formed by the photo-oxidation of polymeric chromophores, or to the quenching effect of the formed peroxide formed during UV-irradiation.…”

Section: Effect Of Uv-irradiation Time On Fluorescence Spectra Of Pursupporting

confidence: 88%

“…The interaction of UV-radiations with polymeric chromophores in presence of air resulted in the formation free radicals. The chemical structure of substituted vinyl benzene is susceptible to photodegradation through the formation of oxyradicals when exposed to UV irradiation [14] [15]. The quantum energies associated with irradiated light in the UV region are sufficient to break many chemical bonds present in the polymer chromophores [20].…”

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confidence: 99%

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Irradiation Effect on Photodegradation of Pure and Plasticized Poly (4-Methylstyrene) in Solid Films

Safi¹,

Mouamin²,

Sieadi³

et al. 2014

MSA

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The photodegradation of irradiated thin films of poly (para-methylstyrene) with 265 nm radiations in the presence of airand as a function of irradiation time has been studied using UV-VIS, fluorescence and FT-IR Spectroscopic techniques. The influence of phthalate and terephthalate plasticizers on stability of poly (para-methylstyrene) towards irradiations was also investigated. Blending with phthalate plasticizers was found to cause a higher efficiency of photodegradation than that obtained in doping with terephthalate plasticizers. The intensity of absorption was also found to increase with time of irradiation and in change in the shape of the spectra at longer wavelength, thus indicating a possibility of photodegradation of polymer chains. The analysis of the FT-IR spectra of the irradiated and non-irradiated samples, shows a predominant absorption associated with carbonyl compounds with 1740 cm −1 . In addition, the observed increase in the intensities of the carbonyl and hydroxyl regions of the FT-IR spectra, have provided an evidence for the photodegradation as well as photo-oxidation of polymeric chains. The presence of the plasticizer in the polymer backbone was found to accelerate the photodegradation of polymeric chains.

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Section: Effect Of Uv-irradiation Time On Fluorescence Spectra Of Pursupporting

confidence: 88%

mentioning

confidence: 99%

Irradiation Effect on Photodegradation of Pure and Plasticized Poly (4-Methylstyrene) in Solid Films

Safi¹,

Mouamin²,

Sieadi³

et al. 2014

MSA

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“…It is more likely that this red shift occurs as result of photodegradation of the polymeric chains, and can be attributed to the formation of conjugated double bonds along the polymer chain during the photodegradation by hydrogen abstraction process (Lacoste, Carlson, Falicki, & Wiles, 1994). The fluorescence band shift of these isomers is in good agreement with that reported with irradiated polystyrene (David et al, 1978), and other poly (substituted styrene) films (Subramanian, 2002). It has been reported that the spectral shift and the fluorescence quenching of irradiated polymer film might be attributed to the energy transportation of the oxides formed by the photooxidation of polymeric chromophores by UV-radiation (Jensen & Kops, 1981).…”

Section: Effect Of Uv-irradiation On Fluorescence Spectra Of Pure Andsupporting

confidence: 85%

UV-Irradiation Effect on the Photodegradation of Plasticized Poly (Ortho, Meta, and Para-Fluorostyrene) Isomers in Solid Films

Ani¹,

Anabtawi²

2012

IJC

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The photostability of thin films of poly (Fluorostyrene) isomers was studied by irradiation with UV-light, in presence of air at room temperature. The irradiated polymer films were exposed to different intervals of time and the degradation process was investigated with absorption, fluorescence and FT-IR spectroscopic methods. The influence of phthalate and terephthalate plasticizers on photo-oxidative degradation was also investigated. Blending with these plasticizers was found to decrease the stability of the irradiated polymers. The same observation was noticed in the photodegradation of other substituted polystyrenes films. The intensity of absorption was also found to increase with time of irradiation and in the intensity of a new absorption band at longer wavelength. In addition the formation on new fluorescence band at longer wavelength for the irradiated film is an evidence of photodegradation of the irradiated polymer films. The FT-IR spectra of irradiated polymers and for blended polymer films with phthalates and terephthalate, showed an increase in the absorption bands of these isomers indicating the possibility of degradation. The mechanism of photodegradation of these isomers was found to be similar to that of polystyrene. The order of photostability of these isomers was found that poly (p-fluorostyrene) is the most stable isomer and, poly (o-fluorostyrene) is the lowest stable isomer towards irradiation effect.

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“…Obviously, the energy transfer mechanism cannot be operative from the very beginning of the photo-oxidation process unless hydroperoxides are already present but it can be expected that it will become predominant as soon as the hydroperoxide concentration is high enough. From that moment, free radicals produced in reaction [12] will initiate the oxidation according to reaction [5] in exactly the same way as radicals produced in reaction [4] when polystyrene is irradiated at 254 nm and the quantum yield of oxygen absorption will be the same. Chain scissions also are produced by the same mechanism in both cases (reaction [6]) and discussion of Scheme 1 is still valid.…”

Section: Kh __÷ Ucrn2mentioning

confidence: 96%

“…This has been ascribed to transfer of energy from the excited phenyl chromophores to hydroperoxide groups formed in the polymer P -P + POOH -P + P0' + oH' [4] These are expected to decompose with a quantum yield close to 0.5, a value measured for cumyl hydroperoxide (a model compound for polystyrene hydroperoxides) in a polystyrene matrix (2). The radicals produced in reaction [4] will then bring about the absorption of oxygen with a quantum yield compatible with the experimental value 0 P0 (or OH') + PH -* POH (or H20) + P'--I P00' [5] This mechanism is supported by the fact that added cumyl hydroperoxide accelerates the rate of photo-oxidation of polystyrene (2).…”

Section: Jjmentioning

confidence: 99%

Recent advances in the photo-oxidation of polymers

Geuskens¹,

David²

1979

Pure and Applied Chemistry

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-Recent results, mainly selected from the authors work on polystyrene, clearly indicate that a sound understanding of the photo-oxidation of polymers cannot be gained without quantum yields determination. These show that transfer of energy has a major role in the initiation of the photo-oxidation because of the high local concentration of reactive groups in polymers. It is also possible to find correlations between the rate of ageing of industrial polymers and the extent of chemical transformation of the materials prior to the exposure to ultra-violet light.

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Photo-oxidation of polymers—III

Cited by 50 publications

References 8 publications

Irradiation Effect on Photodegradation of Pure and Plasticized Poly (4-Methylstyrene) in Solid Films

Irradiation Effect on Photodegradation of Pure and Plasticized Poly (4-Methylstyrene) in Solid Films

UV-Irradiation Effect on the Photodegradation of Plasticized Poly (Ortho, Meta, and Para-Fluorostyrene) Isomers in Solid Films

Recent advances in the photo-oxidation of polymers

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