Photodegradation of Polymers

Rabek, Jan F.

doi:10.1007/978-3-642-80090-0

Cited by 226 publications

(103 citation statements)

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“…23 This behaviour is similar to that observed by Han and coworkers 2,3 and Lai and Liau 1 for the thermal degradation of PEG. They found that the thermal degradation of PEG in air at 80 o C followed a random chain scission oxidation mechanism.…”

Section: Resultssupporting

confidence: 89%

Photo-fenton degradation of poly(Ethyleneglycol)

Santos

Cavalheiro

Poli

et al. 2011

J. Braz. Chem. Soc.

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Polietilenoglicol (PEG) foi fotooxidado usando o sistema foto-Fenton e comparando com a reação no escuro. Os produtos foram analisados por GPC e HPLC. As amostras tratadas na ausência de luz necessitaram 490 min para que a -M w decrescesse em 50%, enquanto que sob irradiação UV essa mesma proporção foi obtida em 10 min. O decaimento exponencial de -M w com um concomitante aumento na polidispersividade e o número de quebras de cadeia caracteriza um mecanismo de quebra de cadeia aleatório. Os produtos da degradação de PEG em ambos os casos mostram a presença de produtos de massa molecular menor, incluindo etilenoglicóis menores e o ácido fórmico. O mecanismo da fotodegradação corresponde a processos consecutivos, onde etilenoglicóis de maior massa molar geram outros de menor massa, envolvendo quebras sucessivas das cadeias do polímero. O estudo demonstra que o processo de foto-Fenton com irradiação UV é um bom método para a decomposição de PEG.Polyethyleneglycol (PEG) was photooxidized in a photo-Fenton system and results compared with the dark reaction. The products were analysed using GPC and HPLC. In the absence of light, PEG samples needed 490 min to reduce their -M w by 50%, whereas under UV irradiation, only 10 min were necessary. The exponential decay of -M w with a concomitant increase in polydispersity and number of average chain scission, characterized a random chain scission mechanism. The degradation products of PEG in both systems showed the presence of lower molecular weight products, including smaller ethyleneglycols and formic acid. The mechanism involves consecutive processes, were the larger ethyleneglycols give rise, successively, to smaller ones. This suggests that the mechanism involves successive scissions of the polymer chain. Irradiated samples decomposed faster than those kept in the dark This study proves that the foto-Fenton method associated with UV-light is a good reactant for PEG photodegradation.

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Section: Resultssupporting

confidence: 89%

Photo-fenton degradation of poly(Ethyleneglycol)

Santos

Cavalheiro

Poli

et al. 2011

J. Braz. Chem. Soc.

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“…Phenols can react with singlet oxygen via electron transfer [16]. It has also been suggested that the photooxidation of polystyrene by singlet oxygen may occur via a radical mechanism as well as by formation of a hydroperoxide [17].…”

Section: Electronic Structure Of Singlet Oxygenmentioning

confidence: 99%

Photosensitized singlet oxygen and its applications

DeRosa

2002

Coordination Chemistry Reviews

2,565

2,134

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“…The peaks around this latter phase are due to oxidation processes. Photo-oxidation is generally considered to be a result of oxidative processes in the amorphous regions, which change the primary structure of a polymer by chain-scission or crosslinking [47,48]. The increase in the intensity of the carbonyl >C=O band (1712 cm -1 ) due to the accumulation and decomposition of hydroperoxides compounds were formed during outdoor exposure.…”

Section: Resultsmentioning

confidence: 99%

“…These mechanisms can be resulted by chain-scission or crosslinking the primary structure of polymer films [11,12]. The study of the photo-oxidation of low density polyethylene has been focused on the exposure of both commercial greenhouses to weathering conditions (outdoor) in the middle of Morocco (Sidi Kacem city).…”

Section: Introductionmentioning

confidence: 99%

Natural Ageing of Stabilized and Unustabilized Ldpe Films Used as Greenhouses Covering Materrials: Atr-Ftir and Sem Analysis

.¹

2015

IJRET

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This article focuses on the study of both stabilized and unstabilized low-density polyethylene films aged under natural weathering in the middle of Morocco (Sidi Kacem city). The study was undertaken on three samples for each LDPE films: a new sample taken as reference; another exposed to outdoor weathering for one year; and a sample exposed for two years. The outdoor exposure effects were followed by analysis of the total reflection Fourier transform infrared spectroscopy (ATR-FTIR). This technique provides information on the main chemical functions and evaluates the internal causes of natural ageing of our samples. The infrared spectra show the formation of hydroperoxides -O-OH, carbonyls >C=O, aliphatic esters R-(CO)-O-R, ether R-O-R, vinyl C=C, vinylidene >C=CH 2 and trans-vinylene RHC=CRH in the amorphous regions. These compounds lead to initiate the mechanism of photo-oxidation of the unstabilized LDPE samples. Therefore, the increase in the formation of oxidation products into the aged samples (LDPEUS) indicates an accelerated degradation of these latter on climatic factors (UV, O2, humidity, rain ...). The UV stabilizer (free radicals scavengers) added to the formulation of LDPE films can delay the attack of the amorphous phase and prevent the formation of compounds that can cause and accelerate photo-oxidation. The results obtained by the infrared have been confirmed by observing the morphology of the samples with scanning electron microscopy technology (SEM).

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Photodegradation of Polymers

Cited by 226 publications

References 0 publications

Photo-fenton degradation of poly(Ethyleneglycol)

Photo-fenton degradation of poly(Ethyleneglycol)

Photosensitized singlet oxygen and its applications

Natural Ageing of Stabilized and Unustabilized Ldpe Films Used as Greenhouses Covering Materrials: Atr-Ftir and Sem Analysis

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