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Formation and the structure of freeze-dried MgO nanoparticle foams and their electrical behaviour in polyethylene

L. K. H. Pallon ; R. T. Olsson ; D. Liu ; A. M. Pourrahimi ; M. S. Hedenqvist ; Anh Hoang (Institutionen för material- och tillverkningsteknik, Högspänningsteknik) ; Stanislaw Gubanski (Institutionen för material- och tillverkningsteknik, Högspänningsteknik) ; U. W. Gedde
Journal of Materials Chemistry A (2050-7488). Vol. 3 (2015), 14, p. 7523-7534.
[Artikel, refereegranskad vetenskaplig]

Electrically insulating low-density polyethylene (LDPE) nanocomposites based on dispersed MgO nanoparticle foams are reported. The foams were obtained via freeze-drying aqueous suspensions of precipitated ca. 40 nm wide and 10 nm thick Mg(OH)(2) nanoparticles and dewatering (calcining) at 400 degrees C, resulting in a 25 times more voluminous powder compared to conventionally dried nanoparticles. This powder handling prior to extrusion melt-processing greatly facilitated the nanocomposite preparation since no particle grinding was necessary. Large quantities of particles were prepared (>5 g), and the nanoparticle foams showed improved dispersion in the LDPE matrix with 70% smaller aggregate sizes compared to the conventionally dried and ground nanopowders. The nature of the nanoparticle foams was evaluated in terms of their dispersion on Si-wafers using ultrasonication as a dispersing aid, which showed to be detrimental for the nanoparticle separation into solitary particles and induced severe aggregation of the calcined nanoparticles. The grind-free MgO nanoparticles/LDPE-composite was evaluated by electrical measurement. The prepared composite showed an initial ca. 1.5 orders of magnitude lower charging current at 10(2) s, and a 4.2 times lower charging current after 16 hours compared to unfilled LDPE. The results open a way for improved insulation to be implemented in the future high-voltage cable system and present a new promising nanoparticle powder handling technique that can be used on a large scale.



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Denna post skapades 2015-06-10. Senast ändrad 2017-10-03.
CPL Pubid: 218169

 

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Institutioner (Chalmers)

Institutionen för material- och tillverkningsteknik, Högspänningsteknik (2005-2017)

Ämnesområden

Energi
Materialvetenskap
Elektroteknik och elektronik

Chalmers infrastruktur