Byproduct-free curing of a highly insulating polyethylene copolymer blend: an alternative to peroxide crosslinking

Mauri, Massimiliano; Peterson, Anna; Senol, Ayça; Elamin, Khalid; Gitsas, Antonis; Hjertberg, Thomas; Matic, Aleksandar; Gkourmpis, Thomas; Prieto, Óscar; Müller, Christian

doi:10.1039/c8tc04494e

Cited by 29 publications

(58 citation statements)

References 35 publications

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“…We chose to focus our study on ternary blends of (i) p(E‐ stat ‐GMA 8 ) and (ii) p(E‐ stat ‐AA 7 ) with a co‐monomer content of 8 wt% GMA and 7 wt% AA, respectively, which we diluted with (iii) neat LDPE. To benchmark our results we used the binary copolymer blend p(E‐ stat ‐GMA 8 ):p(E‐ stat ‐AA 7 ) that we have studied previously . Further, we included the binary blend p(E‐ stat ‐GMA 4.5 ):p(E‐ stat ‐AA 3 ) with a lower co‐monomer content of 4.5 wt% GMA and 3 wt% AA in our analysis, which contains a similar amount of functional groups as compared to a p(E‐ stat ‐GMA 8 ):p(E‐ stat ‐AA 7 ):LDPE ternary blend comprising 50 wt% LDPE.…”

Section: Resultsmentioning

confidence: 99%

“…Chemical structures of the branched statistical copolymers p(E‐ stat‐ AA) and p(E‐ stat ‐GMA), as well as LDPE (top), and the curing reaction between epoxy and carboxyl groups (bottom). Adapted with permission from Mauri et al . Copyright 2018 Royal Society of Chemistry.…”

Section: Resultsmentioning

confidence: 99%

“…As a cut‐off we chose a network density of about 0.3 network points per 1000 carbons, which for the p(E‐ stat ‐GMA 8 ):p(E‐ stat ‐AA 7 ) binary blend corresponds to a gel content of 5% (cf. Mauri et al …”

Section: Resultsmentioning

confidence: 99%

“…To avoid by‐products associated with peroxide crosslinking, we as well as others have recently explored alternative curing concepts based on click chemistry‐type reactions involving a statistical ethylene–glycidyl methacrylate copolymer, p(E‐ stat ‐GMA), which is commonly used as a compatibilizer for polymer blends . In particular, we found that blending of p(E‐ stat ‐GMA) with a statistical ethylene–acrylic acid copolymer, p(E‐ stat ‐AA), results in a formulation that can be extruded below 140 °C, but allows rapid curing during less than 5 min above 160 °C through a click chemistry‐type reaction between epoxy and carboxyl groups . Importantly, because of the absence of any by‐product the crosslinked copolymer blends featured a low DC conductivity of about 2·10 −16 S cm −1 as determined by broad‐band dielectric spectroscopy (BDS) .…”

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

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Click chemistry‐type crosslinking of a low‐conductivity polyethylene copolymer ternary blend for power cable insulation

Mauri

Hofmann

Gómez-Heincke

et al. 2020

Polymer International

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High‐voltage direct‐current power cables are vital for the efficient transport of electricity derived from renewable sources of energy. The most widely used material for high‐voltage power cable insulation – low‐density polyethylene (LDPE) – is usually crosslinked with peroxides, a process that releases unwanted by‐products. Hence, by‐product‐free crosslinking concepts that mitigate the associated increase in electrical conductivity are in high demand. Click chemistry‐type crosslinking of polyethylene copolymer mixtures that contain glycidyl methacrylate and acrylic acid co‐monomers is a promising alternative, provided that the curing reaction can be controlled. Here, we demonstrate that the rate of the curing reaction can be adjusted by tuning the number of epoxy and carboxyl groups. Both dilution of copolymer mixtures with neat LDPE and the selection of copolymers with a lower co‐monomer content have an equivalent effect on the curing speed. Ternary blends that contain 50 wt% of neat LDPE feature an extended extrusion window of up to 170 °C. Instead, at 200 °C rapid curing is possible, leading to thermosets with a low direct‐current electrical conductivity of about 10−16 S cm−1 at an electric field of 20 kV mm−1 and 70 °C. The conductivity of the blends explored here is comparable to or even lower than values measured for both ultraclean LDPE and a peroxide‐cured commercial crosslinked polyethylene grade. Hence, click chemistry curing represents a promising alternative to radical crosslinking with peroxides. © 2019 Society of Chemical Industry

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Click chemistry‐type crosslinking of a low‐conductivity polyethylene copolymer ternary blend for power cable insulation

Mauri

Hofmann

Gómez-Heincke

et al. 2020

Polymer International

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Polyethylene Based Ionomers as High Voltage Insulation Materials

D'Auria

Pourrahimi

Favero

et al. 2023

Adv Funct Materials

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Polyethylene based ionomers are demonstrated to feature a thermo‐mechanical and dielectric property portfolio that is comparable to cross‐linked polyethylene (XLPE), which may enable the design of more sustainable high voltage direct‐current (HVDC) power cables, a crucial component of future electricity grids that seamlessly integrate renewable sources of energy. A new type of ionomer is obtained via high‐pressure/high‐temperature free radical copolymerization of ethylene in the presence of small amounts of ion‐pair comonomers comprising amine terminated methacrylates and methacrylic acid. The synthesized ionomers feature a crystallinity, melting temperature, rubber plateau modulus and thermal conductivity like XLPE but remain melt‐processable. Moreover, the preparation of the ionomers is free of byproducts, which readily yields a highly insulating material with a low dielectric loss tangent and a low direct‐current (DC) electrical conductivity of 1 to 6·10−14 S m−1 at 70 °C and an electric field of 30 kV mm−1. Evidently, the investigated ionomers represent a promising alternative to XLPE‐based high voltage insulation, which may permit to ease the production as well as end‐of‐use recycling of HVDC power cables by combining the advantages of thermoset and thermoplastic materials while avoiding the formation of byproducts.

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Alternative Concepts for Extruded Power Cable Insulation: from Thermosets to Thermoplastics

Pourrahimi,

Mauri,

D'Auria

et al. 2024

Advanced Materials

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The most common type of insulation of extruded high‐voltage power cables is composed of low‐density polyethylene (LDPE), which must be crosslinked to adjust its thermomechanical properties. A major drawback is the need for hazardous curing agents and the release of harmful curing byproducts during cable production, while the thermoset nature complicates reprocessing of the insulation material. This perspective explores recent progress in the development of alternative concepts that allow to avoid byproducts through either click chemistry type curing of polyethylene‐based copolymers or the use of polyolefin blends or copolymers, which entirely removes the need for crosslinking. Moreover, polypropylene‐based thermoplastic formulations enable the design of insulation materials that can withstand higher cable operating temperatures and facilitate reprocessing by remelting once the cable reaches the end of its lifetime. Finally, polyethylene‐based covalent and non‐covalent adaptable networks are explored, which may allow to combine the advantages of thermoset and thermoplastic insulation materials in terms of thermomechanical properties and reprocessability.

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Byproduct-free curing of a highly insulating polyethylene copolymer blend: an alternative to peroxide crosslinking

Abstract: An alternative crosslinking concept for the insulation of HVDC power cables that uses click chemistry is presented.

Cited by 29 publications

References 35 publications

Click chemistry‐type crosslinking of a low‐conductivity polyethylene copolymer ternary blend for power cable insulation

Click chemistry‐type crosslinking of a low‐conductivity polyethylene copolymer ternary blend for power cable insulation

Polyethylene Based Ionomers as High Voltage Insulation Materials

Alternative Concepts for Extruded Power Cable Insulation: from Thermosets to Thermoplastics

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