Characterization of the aging behavior of polyethylene by photoluminescence spectroscopy

Grabmayer, Klemens; Wallner, Gernot M.; Beißmann, Susanne; Schlothauer, Jan C.; Steffen, Ronald; Nitsche, David; Röder, Beate; Buchberger, Wolfgang; Lang, Reinhold W.

doi:10.1016/j.polymdegradstab.2014.04.030

Cited by 31 publications

(19 citation statements)

References 41 publications

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“…For the broad emission around 460 nm, a monotonic increase for constant thermal aging conditions was reported previously . The position of the emission maximum corresponds well to spectra of photo‐excited emission under excitation at 390 nm of heat degraded EVA and other polymers reported in literature . Also luminescence excited at other wavelengths is found in the same spectral region .…”

Section: Resultssupporting

confidence: 87%

“…The luminescence measurement set‐up as well as the measurement procedure has been used previously by the authors for the degradation characterization of commercial PV modules and solid polymer samples . A 375 nm UV‐diode laser (Newport Excelsior 375–16, Stahnsdorf, Germany) is used to excite the luminescence.…”

Section: Methodsmentioning

confidence: 99%

“…It has been used with various experimental conditions also for the characterization of encapsulation EVA . However, the results obtained depend significantly on experimental parameters, mainly excitation wavelength and aging conditions . In general, carbonyl and polyene groups are held responsible for the luminescence of polymers.…”

Section: Introductionmentioning

confidence: 99%

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Correlation of spatially resolved photoluminescence and viscoelastic mechanical properties of encapsulating EVA in differently aged PV modules

Schlothauer

Grabmayer

Wallner

et al. 2016

Progress in Photovoltaics

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The photoluminescence of ethylene vinyl acetate (EVA) in aged photovoltaic modules shows specific spatial patterns on the scale of the cells in the module that depend on the aging conditions. It is the aim of this work to investigate the correlation of these photoluminescence patterns to the viscoelastic mechanical properties of the encapsulating EVA.For this, the degradation under various conditions of two specimen sets of polycrystalline silicon photovoltaic minimodules, comprising EVA as encapsulating polymer, is investigated using spatially resolved, ultraviolet-excited photoluminescence. Samples of the encapsulation EVA are systematically extracted from the modules for spatially resolved dynamic mechanical characterization.A correlation between the spatial distribution of the photoluminescence intensity and the values of storage modulus and loss factor of the EVA is found. An increase in the values for storage modulus and a decrease of the loss factor of the EVA from the edge of the cell towards the center are observed for all samples. We conclude that diffusion-limited oxidation must be considered for aging studies of the encapsulation EVA and that photoluminescence detection can reveal the scale on which such diffusion processes occur.

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Section: Resultssupporting

confidence: 87%

Section: Methodsmentioning

confidence: 99%

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Correlation of spatially resolved photoluminescence and viscoelastic mechanical properties of encapsulating EVA in differently aged PV modules

Schlothauer

Grabmayer

Wallner

et al. 2016

Progress in Photovoltaics

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“…Usually, the amounts of each additive are as small as 0.1% to 2.0% mass fraction [4][5][6][7][8].Consequently, it is difficult to detect the additives using conventional vibrational spectroscopy.However, the formation of conjugated double bonds such as ,-unsaturated carbonyl groups during weathering may contribute significantly to the enhanced fluorescence and/or luminescence emissionwhendegraded samples are illuminated with UV or visible light [4]. Therefore, besides conventional vibrational spectroscopies,fluorescence and luminescence-based analytical techniques can be employed as a synergistic approach to monitor the extent of degradation [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Depth profiling of degradation of multilayer photovoltaic backsheets after accelerated laboratory weathering: Cross-sectional Raman imaging

Lin

Krommenhoek

Watson

et al. 2016

Solar Energy Materials and Solar Cells

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Understanding of thedurability of each individual layer and their interfaces in a multilayered photovoltaic (PV)backsheetis critical to the design and selection of materials for making reliable andhigh performance PV modules. In this study, Raman imaging was used to depth profile the chemical degradation of a multilayer commercial backsheetfilm exposed to ultraviolet (UV) radiationat 85°C, 5% relative humidity (RH, dry) and 85°C,60% RH (humid)on the NIST (National Institute of Standards and Technology) SPHERE(Simulated Photodegradation via High Energy Radiant Exposure).The backsheetfilm wasa multipartlaminate comprising of a pigmented polyethylene terephthalate (PET)-based outer layer, PET core layer and three ethylene vinyl acetate (EVA) layers having different vinyl acetate(VA) contents, along with two inner adhesive layers between PET outer and PET core layers, and PET core and EVA layers. Cross-sectional samples were prepared by cryo-microtomyfor various characterizations.The multilayer structureswere examined by laser scanning confocal andatomic force microscopies, while their chemical degradation profiles were obtained by Raman spectroscopic imaging. Non-uniform degradation was observed in the agedbacksheet film, and both UV and moisture appeared tosignificantly affect the degradation profiles of the multilayers.Severe degradation, indicated by high fluorescence,occurredin the outermost region of the pigmented PET outer layer, and the degradation gradient extended to approximately 20 µm to the bulk. It was also found thattheinner adhesive layerswere severelydeterioratedunder moist condition, indicating thatthe long-termadhesion between the layers could be a major area of concern for multilayer backsheets used in a humid environment. The relationship between the sharp 3 (non-uniform) degradation profile, resultant internal stress, and ultimate failures (cracking and delamination)was discussed as well.

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“…To minimize the UV degradation, UV screeners are added to polymers. The UV screeners absorb light and reduce the amount of light absorption by chromophores such as benzophenones or benzotriazoles, sterically hindered phenols, phosphites, thiosynergists, or hindered amine light stabilizers (HALS) . HALS scavenge the free radicals formed due to photolysis, which prevents further free radical reactions .…”

Section: Introductionmentioning

confidence: 99%

Photooxidative degradation of graphene‐reinforced high‐density polyethylene nanocomposites

Shehzad

Ahmad

Al‐Harthi

2018

J of Applied Polymer Sci

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Natural weathering of high-density polyethylene (HDPE) and its graphene nanocomposites was studied. The nanocomposites, prepared by in situ polymerization of ethylene, were exposed to the natural environment for 30, 60, and 90 days. The effects of weathering on the crystallinity, melting temperature, and lamellar thickness distribution were studied using differential scanning calorimetry. The changes in chain microstructure and molecular weight were determined by crystallization analysis fractionation and gel permeation chromatography, respectively. The effects of weathering on the dynamic mechanical properties and the morphology of the nanocomposite were also determined. The parent HDPE suffered severe degradation as expected. However, graphene-reinforced HDPE nanocomposites show resistance to degradation. The changes in the crystallinity, lamellar thickness, molecular weight, and dynamic mechanical properties of graphene nanocomposites were less pronounced as compared to the parent HDPE.

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Characterization of the aging behavior of polyethylene by photoluminescence spectroscopy

Cited by 31 publications

References 41 publications

Correlation of spatially resolved photoluminescence and viscoelastic mechanical properties of encapsulating EVA in differently aged PV modules

Correlation of spatially resolved photoluminescence and viscoelastic mechanical properties of encapsulating EVA in differently aged PV modules

Depth profiling of degradation of multilayer photovoltaic backsheets after accelerated laboratory weathering: Cross-sectional Raman imaging

Photooxidative degradation of graphene‐reinforced high‐density polyethylene nanocomposites

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