Formation and the structure of freeze-dried MgO nanoparticle foams and their electrical behaviour in polyethylene
Artikel i vetenskaplig tidskrift, 2015

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.


L. K. H. Pallon

Kungliga Tekniska Högskolan (KTH)

R. T. Olsson

Kungliga Tekniska Högskolan (KTH)

D. M. Liu

Kungliga Tekniska Högskolan (KTH)

A. M. Pourrahimi

Kungliga Tekniska Högskolan (KTH)

M. S. Hedenqvist

Kungliga Tekniska Högskolan (KTH)

Tuan Anh Hoang

Chalmers, Material- och tillverkningsteknik, Högspänningsteknik

Stanislaw Gubanski

Chalmers, Material- och tillverkningsteknik, Högspänningsteknik

U. W. Gedde

Kungliga Tekniska Högskolan (KTH)

Journal of Materials Chemistry A

2050-7488 (ISSN)

Vol. 3 7523-7534





Elektroteknik och elektronik