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Surface Modification of Fumed Silica by Dry Silanization for PP/POE-based Dielectric Nanocomposites

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review


Original languageEnglish
Title of host publicationProceedings of the 26th Nordic Insulation Symposium
Place of PublicationNTNU, Norway
PublisherNordic Insulation Symposium
Publication statusPublished - 5 Aug 2019
Publication typeA4 Article in a conference publication
EventNordic Insulation Symposium -
Duration: 1 Jan 1900 → …

Publication series

NameProceedings of the Nordic Insulation Symposium
PublisherNordic Insulation Symposium
ISSN (Electronic)2535-3969


ConferenceNordic Insulation Symposium
Period1/01/00 → …


A systematic study of the influence of surface modification of nanosilica with coupling agents having different polarities on the dielectric properties of a PP/POE/silica blend was performed. The main goal of this investigation was to tailor the chemical composition of the silica surface, in order to modify the charge trapping properties of the nanocomposites. For the modification of the silica surface, a “green” approach was utilized: a dry silanization method, which is performed without the need of a solvent. The results of the thermogravimetric analysis (TGA) indicate that the dry process is an effective method to perform silica surface modification using alkoxysilanes.

The charge trapping properties were studied by Thermally Stimulated Depolarization Current (TSDC) measurements. The obtained TSDC results show significant differences in charge trapping properties of PP/POE composites filled with differently modified silicas. Polar functional groups attached to the surface of the silica appear to have a strong effect on the charge trapping properties: The trap depth distribution becomes deeper and the trap density decreases to significantly lower levels.

All results show that incorporation of surface modified nanosilica into a PP/POE matrix is a promising approach to tailor its dielectric properties. Further development of these composites may lead to benefits for application in high-voltage cable and capacitor applications.

Keywords: silica surface modification, dry silanization, charge trapping, PP, POE, TSDC, high voltage cable.