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

Xiaozhen He, Ilkka Rytöluoto (Contributor), Amirhossein Mahtabani (Contributor), Eetta Saarimäki (Contributor), Kari Lahti (Contributor), Mika Paajanen (Contributor), Rafal Piotr Anyszka (Contributor), Wilma K. Dierkes (Contributor), Anke Blume (Contributor)

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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.
Original languageEnglish
Number of pages5
Publication statusPublished - 12 Jun 2019
Event26th Nordic Insulation Symposium on Materials, Components and Diagnostics - Tampere, Finland
Duration: 11 Jun 201913 Jun 2019
Conference number: 26


Conference26th Nordic Insulation Symposium on Materials, Components and Diagnostics
Abbreviated titleNORD-IS 2019


  • silica surface modification
  • dry silanization
  • charge trapping
  • TSDC
  • high voltage cable


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