Natural and artificial weathering of polyethylene plastics

Howard, John B.; Gilroy, H. M.

doi:10.1002/pen.760090409

Cited by 35 publications

(13 citation statements)

References 10 publications

(6 reference statements)

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“…The excellent UV stabilization characteristics of CB nanoparticles can delay the formation of free radicals in the polymer, which are typical species essential for the process of UV degradation [12]. Also, small particle sized-CBs are known to have the greatest UV stabilizing efficiency [12,15]. In E250 sample, CB nanoparticles had an optimum concentration and suitable particles size and thus no microcracks were appeared on surface of the coating.…”

Section: Microcracking Due To Uv Exposurementioning

confidence: 98%

“…Carbonyl index = Absorbance I 1720 /Absorbance I 2900 (15) where I 1720 and I 2900 are intensity of absorbance peaks at 1720 and 2900 cm −1 , respectively. The absorbance intensity was calculated by Eq.…”

Section: Analysis Of Photo-oxidationmentioning

confidence: 99%

“…Its UV stabilization character is related to the type and particle size of the CB as well as to its concentration and its degree of dispersion in the polymer [13,14]. Small particle sized-CBs are known to have the greatest UV stabilizing efficiency but they tend to agglomerate into aggregates or clusters which cannot easily be dispersed [12,13,15]. The understanding of the role of CB towards oxidation may be summarized in terms of an antioxidant effect, probably via catalytic decomposition of peroxides and free radical scavenger with great effectiveness, balanced by a pro-oxidant property under some conditions [13,16].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Improving the UV degradation resistance of epoxy coatings using modified carbon black nanoparticles

Ghasemi-Kahrizsangi¹,

Neshati²,

Shariatpanahi³

et al. 2015

Progress in Organic Coatings

113

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Section: Microcracking Due To Uv Exposurementioning

confidence: 98%

Section: Analysis Of Photo-oxidationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Improving the UV degradation resistance of epoxy coatings using modified carbon black nanoparticles

Ghasemi-Kahrizsangi¹,

Neshati²,

Shariatpanahi³

et al. 2015

Progress in Organic Coatings

113

View full text Add to dashboard Cite

“…It has been reported [25,38] that increased UV stability of polyethylene can be achieved by increasing the loading of carbon black in the material up to a level of approximately 5% (wt/wt). At concentrations greater than this there appears to be no further improvement in UV stability.…”

Section: Hdpe/carbon Black Formulationsmentioning

confidence: 99%

“…At concentrations greater than this there appears to be no further improvement in UV stability. Furthermore, it has been pointed out that the assessment of the photostability of samples containing levels of carbon black greater than 5 % (wt/wt) cannot be made reliably using conventional tests, such as brittle point measurement, due to the large reduction in physical properties of the material containing higher levels of carbon black [38]. The value of the initial quantum yield for oxygen uptake approaches asymptotically a lower limit of approximately 1.8 x 10 ...2 as the concentration of carbon black increases (see Fig.…”

Section: Hdpe/carbon Black Formulationsmentioning

confidence: 99%

The effects of pigments on the photostability of polyethylene

Bigger

Delatycki

1989

J Mater Sci

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The affect of carbon black and various colourizing pigments on the ultraviolet (UV) stability of high and low density polyethylene (HDPE and LDPE) was determined using a novel method for the analysis of oxygen uptake profiles. Samples were exposed to 0.27 W m -2 (measured at 340nm) UV irradiation at 25.0 4-0.1° C in air at 1.0atm. The usefulness of this method of assessment of UV stability is demonstrated. The method also enables the rapid collection of data that enable the comparison of the relative photostabilities of experimental and commercial formulations containing pigments and stabilizing additives. The results show that carbon black is an effective UV screening agent for HDPE when added at levels as low as 0.05% (wt/wt) and that increased photoprotection is achieved with increasing concentration of carbon black, up to 5% (wt/wt), above which there is no further significant increase in photostability. LDPE containing ultramarine blue pigment (Na7AI6SiaO24S3) exhibits relatively poor photostability, whereas ferric oxide (Fe203) and chrome orange (PbCrO4. PbO) pigments are better photostabilizers for this material. Cadmium sulphide (CdS) was found to photosensitize LDPE. A compound containing 0.10% (wt/wt) carbon black, 0.12% (wt/wt) titanium dioxide (TiO2) and 1.78% (wt/wt) phthalocyanine green (C33H2N8CI14Cu) is an effective formulation for the stabilization of LDPE. Formulations of LDPE containing ultramarine blue-TiO2 or ferric oxidecarbon black combinations absorb heat on exposure and this may affect their photostability.

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Weathering

Searle¹

2001

Encyclopedia of Polymer Science and Technology

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The irreversible changes in chemical and physical properties of polymeric materials exposed to the environment are caused by the combined action of all weather factors, including solar radiation, heat, moisture, oxygen, and atmospheric pollutants. However, the actinic radiation of the sun absorbed by materials is the critical factor. It initiates the chemical reactions that lead to degradation through its bond breaking capabilities. The wavelength specificity of degradation, and its material dependency are illustrated by the activation spectra of various types of polymers. The contributions of the other major environmental factors to weathering and various types of outdoor weathering tests are described. The significant advances in development of weatherable polymeric materials have increased the need for more rapid evaluations by both outdoor and laboratory accelerated tests. Their validity depends on how well they simulate the effects of exposure to end‐use environments in terms of failure modes, mechanism of degradation, and stability rankings of materials. The most important factor in good correlations between laboratory accelerated and outdoor weathering tests is adequate simulation of the spectral power distribution of the natural source over the full range of actinic wavelengths. The types commonly used in laboratory accelerated devices are compared with solar radiation and the effects of their deviations in the uv and visible regions are discussed. The effect of increased stress levels of irradiance, temperature, and moisture on acceleration factors and on correlation with natural weathering tests are described. Techniques for predicting lifetimes under natural weathering based on laboratory accelerated tests are reviewed.

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Natural and artificial weathering of polyethylene plastics

Cited by 35 publications

References 10 publications

Improving the UV degradation resistance of epoxy coatings using modified carbon black nanoparticles

Improving the UV degradation resistance of epoxy coatings using modified carbon black nanoparticles

The effects of pigments on the photostability of polyethylene

Weathering

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