Combining Theory and Experiment to Study the Photooxidation of Polyethylene and Polypropylene

Bertoldo, Monica; Bronco, Simona; Cappelli, Chiara; Gragnoli, and Tania; Andreotti, Leonardo

doi:10.1021/jp035427h

Cited by 47 publications

(36 citation statements)

References 21 publications

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“…The mechanism commonly invoked in the radiation-induced oxidation process of PP is the attack of free radicals on the polymer chains. The alkyl radicals generated in this way react with oxygen, giving rise to hydroperoxides, alcohols, and carbonyl compounds such as carboxylic acids, ketones and esters, whose relative percentage depends on oxidation conditions [55,56]. The quantification of the various oxidation products of PP (as a result of gamma, photo, and thermal oxidation) was done by Lacoste et al [57,58].…”

Section: Resultsmentioning

confidence: 99%

Complete relaxation map of polypropylene: radiation-induced modification as dielectric probe

Suljovrujić

2012

Polym. Bull.

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The molecular relaxation behaviour of isotactic polypropylene (iPP) exposed to gamma radiation in air to various absorbed doses (up to 700 kGy) has been investigated by dielectric loss (tan d) analysis; the polar (mainly carbonyl and hydroperoxide) groups that were introduced by radiation-induced oxidation were considered as tracer groups. All relaxation zones (a, b, c and d in the order of decreasing temperature), between 25 K and melting temperature, were studied in the frequency range from 1 kHz to 1 MHz. The changes observed in the dielectric relaxation spectra were related to the modifications in the structural and morphological parameters attributed to exposure of the iPP samples to radiation. Wide-angle X-ray diffraction was used to investigate radiation-induced changes in the crystalline structure and degree of crystallinity, since the a relaxation is connected with this phase. Infrared spectroscopy and gel measurements were used to determine the changes in the oxidative degradation and the degree of network formation, respectively. Conclusions derived using different methods were compared. This study reveals high dielectric and/or relaxation sensitivity of iPP to gamma radiation. Disappearance of the lowtemperature dielectric (c and d) relaxations together with large changes in intensity, position and activation energy of the dielectric a relaxation are observed with gamma irradiation and are mainly connected with oxidative degradation in iPP structure.

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Section: Resultsmentioning

confidence: 99%

Complete relaxation map of polypropylene: radiation-induced modification as dielectric probe

Suljovrujić

2012

Polym. Bull.

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“…The phenomenon is also more pronounced in the case of the samples containing GA. 3 represents the FTIR spectra of the neat LLDPE film before and after different UV exposure time intervals. The significant changes of the spectra occurred in the carbonyl (1840-1670 cm -1 ), hydroxyl (3500-3300 cm -1 ) and vinyl (909 and 1641 cm -1 ) absorption bands [33][34][35][36]. The absorption band around 1712 cm -1 , which can be assigned to the C=O stretching of a ketone group grows in intensity with the UV exposure time and at the same time a band broadening is observed indicating the presence of more than one type of carbonyl group.…”

Section: Mechanical Propertiesmentioning

confidence: 99%

Study on the effect of galbanic acid on photo-oxidative degradation of linear low density polyethylene (LLDPE) films

Jahanmardi

Assempour

2008

E-Polymers

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Photo-oxidative degradation of LLDPE films (~ 250 μm thick) containing varying amounts of galbanic acid (a type of coumarin derivatives) was investigated by exposing the films to an artificial sunlight (emitted by 300 W OSRAM UltraVitalux lamps) at 40 ○ C for extended time periods. Photo-oxidative degradation of the neat polymer film and the LLDPE films containing benzophenone (an active photo-initiator for PE) and coumarin alone were also studied under similar conditions for comparison. The rate of photo-oxidation was assessed by measuring tensile properties, gel content, carbonyl index, molecular weight and density. It was shown that galbanic acid was highly effective in accelerating photo-oxidation of LLDPE films and an outstanding acceleration of photo-oxidation was observed for the film containing 0.2 wt % of galbanic acid in comparison with the film containing the same amount of benzophenone. However, the film containing coumarin did not exhibit considerable difference in behaviour in photo-oxidation relative to the neat LLDPE film during the exposure time. On the basis of the obtained results, the prooxidant activity of galbanic acid was described in terms of activity of the functional groups existing in the substituted moiety of its molecules.

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“…The photodegradation of pure PE has been extensively studied [20][21][22]. The reaction of PE under ultraviolet irradiation occurred via direct absorption of photons by the PE macromolecule to create excited states, and then undergo chain scission, branching cross-linking and oxidation reactions.…”

Section: Photocatalytic Degradation Mechanism Of Pe-(tio 2 / Cupc) Samentioning

confidence: 99%

Enhancement of photocatalytic degradation of polyethylene plastic with CuPc modified TiO2 photocatalyst under solar light irradiation

Zhao

Chen

et al. 2008

Applied Surface Science

122

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Solid-phase photocatalytic degradation of polyethylene (PE) plastic, one of the most common commercial plastic, over copper phthalocyanine (CuPc) modified TiO 2 (TiO 2 /CuPc) photocatalyst was investigated in the ambient air under solar light irradiation. Higher PE weight loss rate, greater texture change; more amount of generated CO 2 , which is the main product of the photocatalytic degradation of the composite PEC plastic can be achieved in the system of PE-(TiO 2 /CuPc) in comparison with PE-TiO 2 system. The CuPc promoted charge separation of TiO 2 and enhanced the photocatalytic degradation of PE based on the analysis of surface photovoltage spectroscopy (SPS). During the photodegradation of PE plastic, the reactive oxygen species generated on TiO 2 or TiO 2 /CuPc particle surfaces play important roles. The present study demonstrates that the combination of polymer plastic with TiO 2 /CuPc composite photocatalyst in the form of thin film is a practical and useful way to photodegrade plastic contaminants under solar light irradiation. # 2007 Published by Elsevier B.V.

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Combining Theory and Experiment to Study the Photooxidation of Polyethylene and Polypropylene

Cited by 47 publications

References 21 publications

Complete relaxation map of polypropylene: radiation-induced modification as dielectric probe

Complete relaxation map of polypropylene: radiation-induced modification as dielectric probe

Study on the effect of galbanic acid on photo-oxidative degradation of linear low density polyethylene (LLDPE) films

Enhancement of photocatalytic degradation of polyethylene plastic with CuPc modified TiO2 photocatalyst under solar light irradiation

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