The photo-oxidation of polymers—1. Initiation of polystyrene photo-oxidation

Kuzina, S. I.; Михайлов, А. И.

doi:10.1016/0014-3057(93)90250-j

Cited by 28 publications

(16 citation statements)

References 4 publications

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“…To date, a rather large amount of data has been accumulated on the photochemistry and radiation chemistry of polystyrene [11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

“…The quantum yield of this reaction, as determined by various authors, is 10 -3 to 10 -5 [13]. Even after radical formation, their benzene rings still fulfill the function of accumulation of the energy of the absorbed radiation.…”

mentioning

confidence: 98%

“…However, obviously the initial step of such mechanisms is formation of radicals on exposure to radiation. This process has been quite well studied for polystyrene [9,13,14].…”

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confidence: 99%

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Fluorescence and absorption of a polystyrene-based scintillator exposed to UV laser radiation

et al. 2007

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We have established that exposure of polystyrene-based scintillator samples to UV laser radiation (248 nm) leads to a significant decrease in the fluorescence intensity. We have carried out a spectral analysis of the luminescent and absorption properties of the scintillator, which allowed us to determine the major factor in the decrease in luminescence intensity of the samples exposed to UV radiation. We propose a new hypothesis for the mechanism of the processes leading to the decrease in light output of the scintillator during operation. Introduction.A plastic scintillator is a composite consisting of an optically transparent plastic and added luminophores. A plastic scintillator displays bright luminescence when exposed to ionizing radiation and is rather stable relative to such exposure. Scintillators are made from such composites in the form of optical fibers, films, and plates with large surface area, and also bulk blocks of any size or shape, which significantly expands the possibilities for their application. The advantage of plastic scintillators is their fast response (the radioluminescence lifetime ranges from fractions of a nanosecond to several nanoseconds). They are used for radiation detection and dosimetry.The most widely used plastic scintillators are based on polystyrene with added luminophores: p-terphenyl (p-TP) and 1,4-bis(2-(5-phenyloxazolyl))benzene (POPOP). Polystyrene plastic is the most radiation resistant among the known synthetic polymers [1]; it has high transparency over a broad spectral range (λ > 290 nm). However, we should point out that the indicated characteristic is seen only in the very pure polymer. Commercial polystyrene contains impurities and structural defects absorbing in the 290-400 nm region [2][3][4].A general disadvantage of plastic scintillators is gradual loss of scintillation efficiency during operation. As the absorbed dose of ionizing radiation increases, the light output of the scintillator decreases. As the characteristic for radiation resistance, we take the value of the absorbed dose D 1/2 at which the light output is half of the initial value. For polystyrene scintillators, D 1/2 ≈ 600 kGy [3].The radiation-induced physicochemical changes leading to a decrease in the light output of a plastic scintillator have been the subject of many studies [3,[5][6][7][8][9][10]. Special attention has been focused on the loss of transparency in the plastic. It has been established that this is due to the appearance of "induced" absorption bands that are relatively intense in the 300-400 nm region and low-intensity in the visible region. The bands that appeared were assigned to macroradicals formed on exposure to radiation, some of which proved to be short-lived while others were rather stable. These data provided the basis for established ideas about the reasons for radiation-induced wear in plastic scintillators. We should point out that in some papers (see, for example, [9]), bands were seen which could not be attributed to radicals, and they were assigned to unident...

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“…To date, a rather large amount of data has been accumulated on the photochemistry and radiation chemistry of polystyrene [11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 98%

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Fluorescence and absorption of a polystyrene-based scintillator exposed to UV laser radiation

et al. 2007

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“…Although photochemical (õ 440 nm excitation) and thermal degradation reactions of bulk polystyrene have been thoroughly investigated, [8][9][10][11][12][13][14] the photochemical reactions of individual micron diameter polystyrene latex particles isolated in a visible radiation trap have only recently been described. 15 Many different photochemically initi- pended drop.…”

Section: Resultsmentioning

confidence: 99%

Rapid spectroscopic confirmation of the presence of polystyrene in polymer particles of mixed composition

Crawford¹,

Hughes²

1998

J. Polym. Sci. B Polym. Phys.

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“…Compared to the pristine azide-telechelic polystyrene, M60 weight loss decreased of about 40°C, according to Td 10 . This lower thermal stability for M60 is probably the result of chain degradations by photo-oxidation during UV crosslinking process [40][41][42].…”

Section: (C-f) + M(c-c) + M(c-n)mentioning

confidence: 98%

Proton Conducting Sulphonated Fluorinated Poly(Styrene) Crosslinked Electrolyte Membranes

Soules¹,

Améduri²,

Boutevin³

et al. 2011

Fuel Cells

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Potential membranes for polymer electrolyte membrane fuel cell based on crosslinked sulphonated fluorinated polystyrenes (PS) were synthesised in two steps. First, azide‐telechelic polystyrene was obtained by iodine transfer polymerisation of styrene in the presence of 1,6‐diiodoperfluorohexane followed by azido chain‐end functionalisation. Then azide‐telechelic polystyrene was efficiently crosslinked with 1,10‐diazido‐1H,1H,2H,2H,9H,9H,10H,10H‐perfluorodecane under UV irradiation. After 45 min only, almost completion of azide crosslinking could be achieved, resulting in crosslinked membranes with insoluble fractions higher than 95%. The sulphonation of the crosslinked membranes afforded ionic exchange capacities (IECs) ranging from 2.2 to 3.2 meq g–1. The hydration number was shown to be very high (from 30 to 75), depending on both the content of perfluorodecane and of sulphonic acid groups. The morphology of the membranes, assessed by small‐angle X‐ray scattering, was found to be a lamellar‐type structure with two types of ionic domains. For the membrane that exhibited an IEC value of 2.2 meq·g–1, proton conductivity was in the same range as that of Nafion® (120–135 mS·cm–1), whereas the membrane IEC value of 3.2 meq·g–1 showed a proton conductivity higher than that of Nafion® in liquid water from 25 to 80 °C, though a high water uptake.

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The photo-oxidation of polymers—1. Initiation of polystyrene photo-oxidation

Cited by 28 publications

References 4 publications

Fluorescence and absorption of a polystyrene-based scintillator exposed to UV laser radiation

Fluorescence and absorption of a polystyrene-based scintillator exposed to UV laser radiation

Rapid spectroscopic confirmation of the presence of polystyrene in polymer particles of mixed composition

Proton Conducting Sulphonated Fluorinated Poly(Styrene) Crosslinked Electrolyte Membranes

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