EPR studies on the interaction between additives and polyethylene matrix initiated by gamma radiation

Przybytniak, G.; Sadło, Jarosław; Walo, Marta

doi:10.3144/expresspolymlett.2020.45

Cited by 8 publications

(5 citation statements)

References 31 publications

(37 reference statements)

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“…In electron paramagnetic resonance experiments on cross linked polyethylene exposed to γ-rays, it was found that the main issue was scission of the C-H bonds, and consequently the creation of a free radical and paired electrons that were mobile along the backbone of the polymer [40]. At noncryogenic temperatures these phenomena were all rather short lived (<minutes).…”

Section: Nature and Life Time Of Free Radicals And Electronic Defects...mentioning

confidence: 99%

When x-rays alter the course of your experiments*

Bras

Myles

Felici³

2021

J. Phys.: Condens. Matter

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The continuing increase in the brilliance of synchrotron radiation beamlines allows for many new and exciting experiments that were impossible before the present generation of synchrotron radiation sources came on line. However, the exposure to such intense beams also tests the limits of what samples can endure. Whilst the effects of radiation induced damage in a static experiment often can easily be recognized by changes in the diffraction or spectroscopy curves, the influence of radiation on chemical or physical processes, where one expects curves to change, is less often recognized and can be misinterpreted as a ‘real’ result instead of as a ‘radiation influenced result’. This is especially a concern in time-resolved materials science experiments using techniques as powder diffraction, small angle scattering and x-ray absorption spectroscopy. Here, the effects of radiation (5–50 keV) on some time-resolved processes in different types of materials and in different physical states are discussed. We show that such effects are not limited to soft matter and biology but rather can be found across the whole spectrum of materials research, over a large range of radiation doses and is not limited to very high brilliance beamlines.

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Section: Nature and Life Time Of Free Radicals And Electronic Defects...mentioning

confidence: 99%

When x-rays alter the course of your experiments*

Bras

Myles

Felici³

2021

J. Phys.: Condens. Matter

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“…According to Hettal et al [19] the crystallinity of the same samples increases during aging, approximately to the same degree per dose of radiation in both aging regimes for the non-protected XLPE. The crystallinity increase effect may explain the change in stability of radicals, both oxygen-and carbon-centred, as it is known from the literature that radicals in the crystalline phase are significantly more stable as a result of inhibition of chain motions [15].…”

Section: Resultsmentioning

confidence: 99%

“…The mechanism of antioxidant reactions is not fully understood. In our previous work, the interpretation of EPR signals allowed us to determine the paramagnetic species participating in these reactions [15].…”

Section: Research Design and Approachmentioning

confidence: 99%

Radical Composition and Radical Reaction Kinetics in the Probe-Irradiated XLPE Samples as a Potential Source of Information on Their Aging Degree

Lewandowska

Sadło

2022

Materials

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Polyethylene is a model polyolefin, and a widely used material for the manufacture of many products, including cable sheaths. Understanding degradation mechanisms at the atomic scale leading to oxidation during aging is crucial for many long-term applications. The concentrations of radicals derived from oxidation and chain scission during radio-oxidation, as well as their ratio, are important parameters controlling the predominance of chain scission or crosslinking of the polymer. In this work, we propose a cryogenic EPR technique for measuring oxidation- and fragmentation-derived radicals as a less-destructive method for the evaluation of cable insulation aging and performance capability. We investigate the effect of the low-dose and high-dose radiation aging on the formation of free radicals in the polymer matrix that are both unprotected and protected by antioxidants. The stability of radicals after aging is a determinant of macroscopic processes and structural changes during aging. Under the conditions of the higher dose rate, the peroxy radical buildup is lower per dose. Peroxy radical buildup is followed by decay during aging, in accordance with POOH content. Our results allow the prediction of the capability of the antioxidant to protect the XLPE material in the function of dose and time.

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“…However, massive waste CLPE cables become a pollution source bringing a heavy burden to ecology at the end of their service life. , The irreversible cross-linking structure and the incorporation of various additives (including carbon black, lubricants, flame retardants, etc.) make it extremely difficult to recycle or reuse the CLPE cables. , Nowadays, landfill or incineration is the main method for disposing waste CLPE cables, causing serious environmental pollution and a waste of resources . Therefore, it is a great challenge to develop high-efficient and environmental recycling technology of waste CLPE cables, particularly for converting them into high value-added materials.…”

Section: Introductionmentioning

confidence: 99%

Electrically Conductive and All-Weather Materials from Waste Cross-Linked Polyethylene Cables for Electromagnetic Interference Shielding

Xie

Ye²,

Chen

et al. 2022

Ind. Eng. Chem. Res.

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With the explosive growth of intelligent devices, low-cost multifunctional materials will be in great demand in the near future. Preparation of flexible polymer composites from waste plastics can not only reduce the production cost but also alleviate the environmental concern. Herein, the thermoplastic polymers from waste cross-linked polyethylene (CLPE) cables were efficiently recycled by partially breaking the cross-linking points in the solid state and, thus, fully utilized in the low-cost, high-strength, and allweather electromagnetic interference (EMI) shielding materials. Briefly, with the assistance of the homemade solid-state shear milling (S3M) reactor, the waste CLPE cables were converted into fine micropowders at a large scale. The obtained decross-linked CLPE powders were coated with carbon nanotubes (CNTs), and then the coated complex particles were compacted together during the microwave sintering process. In this way, the segregated structure with CNTs selectively enriched at the interfaces of the CLPE phases was successfully constructed by taking full advantage of the selective heating mode of the microwave and the remaining crosslinked structure in CLPE. The sintered CLPE/CNTs containing 7.0 wt % CNTs exhibit an electrical conductivity of 22.6 S/m and an EMI shielding effectiveness (EMI SE) of 35.0 dB, respectively. More importantly, the resulting composite shows superior stability in electrical and EMI shielding properties even under extreme conditions, such as acid/alkali solution soaking and repeated bending deformation. The segregated CLPE/CNT composite also shows excellent mechanical properties with tensile strength above 20 MPa and elongation at a break of 280%. This interfacial engineering strategy offers an effective method to convert the unrecyclable waste plastic into value-added materials, showing great significance in resource recycling utilization.

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EPR studies on the interaction between additives and polyethylene matrix initiated by gamma radiation

Cited by 8 publications

References 31 publications

When x-rays alter the course of your experiments*

When x-rays alter the course of your experiments*

Radical Composition and Radical Reaction Kinetics in the Probe-Irradiated XLPE Samples as a Potential Source of Information on Their Aging Degree

Electrically Conductive and All-Weather Materials from Waste Cross-Linked Polyethylene Cables for Electromagnetic Interference Shielding

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