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

Xiaozhen He, Amirhossein Mahtabani, Ilkka Rytöluoto, Eetta Saarimäki, Kari Lahti, Mika Paajanen, Rafal Anyszka, Wilma Dierkes, Anke Blume

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

Abstract

Novel nanocomposites for dielectric applications based on a polypropylene (PP) blend filled with nanosilica are developed in the frame of the European ‘GRIDABLE’ project. A systematic study of the influence of surface modification of the nanosilica on the dielectric properties of the PP/silica blend was performed. The main goal of this investigation was to modify the chemical composition of the silica surface, which is expected to improve 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. Eight different silanes were investigated in this study, which are categorized into three different groups: I)Aliphatic silanes with a different number of alkoxy groups II)Hydrocarbon silanes containing delocalized electron clouds III)Polar silanes containing hetero elements (nitrogen, sulfur or oxygen) The results of the thermogravimetric analysis (TGA) show higher weight loss of the modified silicas in comparison to the unmodified one. This indicates 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 that the trap density peak is not significantly shifted in temperature when the silica is modified with functional groups elementally similar to the polymer matrix. However, their incorporation influences the traps density and suppress the deeper traps occurring near the range of the melting temperature of PP. When the silica surface is modified with a precursor containing a hetero element, it has an effect on both, trap level depth as well as density. Depending on the type of the hetero element (sulfur, nitrogen, oxygen), the trap depth shifted to higher temperatures, and the trap density decreased to significantly lower levels. Nitrogen appears to have the strongest effect on the charge trap properties. All these first stage of results show that incorporation of modified nanosilica into a PP matrix seems to be a promising approach to tailor its electric properties. Further development of these composites would lead to benefits for high-voltage cable and capacitors applications.
Original languageEnglish
Title of host publication2nd International Conference on Electrical Materials and Power Equipment, ICEMPE 2019
PublisherInstitute of Electrical and Electronic Engineers IEEE
Pages254-259
Number of pages6
ISBN (Electronic)978-1-5386-8434-4
ISBN (Print)978-1-5386-8434-4
DOIs
Publication statusPublished - 2019
MoE publication typeA4 Article in a conference publication
Event2nd International Conference on Electrical Materials and Power Equipment, ICEMPE - Guangzhou, China
Duration: 7 Apr 201910 Apr 2019

Conference

Conference2nd International Conference on Electrical Materials and Power Equipment, ICEMPE
Abbreviated titleICEMPE
CountryChina
CityGuangzhou
Period7/04/1910/04/19

Fingerprint

polypropylene
nanocomposites
traps
silicon dioxide
silanes
nitrogen
depolarization
sulfur
trapping
electron clouds
oxygen
matrices
cables
dielectric properties
high voltages
capacitors
chemical composition
hydrocarbons
melting
composite materials

Keywords

  • silica surface modification
  • dry silanization
  • polypropylene dielectric nanocomposites
  • charge trapping properties
  • TSDC
  • high voltage cable

Cite this

He, X., Mahtabani, A., Rytöluoto, I., Saarimäki, E., Lahti, K., Paajanen, M., ... Blume, A. (2019). Surface Modification of Fumed Silica by Dry Silanization for PP-based Dielectric Nanocomposites. In 2nd International Conference on Electrical Materials and Power Equipment, ICEMPE 2019 (pp. 254-259). [8727244] Institute of Electrical and Electronic Engineers IEEE. https://doi.org/10.1109/ICEMPE.2019.8727244
He, Xiaozhen ; Mahtabani, Amirhossein ; Rytöluoto, Ilkka ; Saarimäki, Eetta ; Lahti, Kari ; Paajanen, Mika ; Anyszka, Rafal ; Dierkes, Wilma ; Blume, Anke. / Surface Modification of Fumed Silica by Dry Silanization for PP-based Dielectric Nanocomposites. 2nd International Conference on Electrical Materials and Power Equipment, ICEMPE 2019. Institute of Electrical and Electronic Engineers IEEE, 2019. pp. 254-259
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abstract = "Novel nanocomposites for dielectric applications based on a polypropylene (PP) blend filled with nanosilica are developed in the frame of the European ‘GRIDABLE’ project. A systematic study of the influence of surface modification of the nanosilica on the dielectric properties of the PP/silica blend was performed. The main goal of this investigation was to modify the chemical composition of the silica surface, which is expected to improve 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. Eight different silanes were investigated in this study, which are categorized into three different groups: I)Aliphatic silanes with a different number of alkoxy groups II)Hydrocarbon silanes containing delocalized electron clouds III)Polar silanes containing hetero elements (nitrogen, sulfur or oxygen) The results of the thermogravimetric analysis (TGA) show higher weight loss of the modified silicas in comparison to the unmodified one. This indicates 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 that the trap density peak is not significantly shifted in temperature when the silica is modified with functional groups elementally similar to the polymer matrix. However, their incorporation influences the traps density and suppress the deeper traps occurring near the range of the melting temperature of PP. When the silica surface is modified with a precursor containing a hetero element, it has an effect on both, trap level depth as well as density. Depending on the type of the hetero element (sulfur, nitrogen, oxygen), the trap depth shifted to higher temperatures, and the trap density decreased to significantly lower levels. Nitrogen appears to have the strongest effect on the charge trap properties. All these first stage of results show that incorporation of modified nanosilica into a PP matrix seems to be a promising approach to tailor its electric properties. Further development of these composites would lead to benefits for high-voltage cable and capacitors applications.",
keywords = "silica surface modification, dry silanization, polypropylene dielectric nanocomposites, charge trapping properties, TSDC, high voltage cable",
author = "Xiaozhen He and Amirhossein Mahtabani and Ilkka Ryt{\"o}luoto and Eetta Saarim{\"a}ki and Kari Lahti and Mika Paajanen and Rafal Anyszka and Wilma Dierkes and Anke Blume",
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He, X, Mahtabani, A, Rytöluoto, I, Saarimäki, E, Lahti, K, Paajanen, M, Anyszka, R, Dierkes, W & Blume, A 2019, Surface Modification of Fumed Silica by Dry Silanization for PP-based Dielectric Nanocomposites. in 2nd International Conference on Electrical Materials and Power Equipment, ICEMPE 2019., 8727244, Institute of Electrical and Electronic Engineers IEEE, pp. 254-259, 2nd International Conference on Electrical Materials and Power Equipment, ICEMPE , Guangzhou, China, 7/04/19. https://doi.org/10.1109/ICEMPE.2019.8727244

Surface Modification of Fumed Silica by Dry Silanization for PP-based Dielectric Nanocomposites. / He, Xiaozhen; Mahtabani, Amirhossein; Rytöluoto, Ilkka; Saarimäki, Eetta; Lahti, Kari; Paajanen, Mika; Anyszka, Rafal; Dierkes, Wilma; Blume, Anke.

2nd International Conference on Electrical Materials and Power Equipment, ICEMPE 2019. Institute of Electrical and Electronic Engineers IEEE, 2019. p. 254-259 8727244.

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

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T1 - Surface Modification of Fumed Silica by Dry Silanization for PP-based Dielectric Nanocomposites

AU - He, Xiaozhen

AU - Mahtabani, Amirhossein

AU - Rytöluoto, Ilkka

AU - Saarimäki, Eetta

AU - Lahti, Kari

AU - Paajanen, Mika

AU - Anyszka, Rafal

AU - Dierkes, Wilma

AU - Blume, Anke

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N2 - Novel nanocomposites for dielectric applications based on a polypropylene (PP) blend filled with nanosilica are developed in the frame of the European ‘GRIDABLE’ project. A systematic study of the influence of surface modification of the nanosilica on the dielectric properties of the PP/silica blend was performed. The main goal of this investigation was to modify the chemical composition of the silica surface, which is expected to improve 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. Eight different silanes were investigated in this study, which are categorized into three different groups: I)Aliphatic silanes with a different number of alkoxy groups II)Hydrocarbon silanes containing delocalized electron clouds III)Polar silanes containing hetero elements (nitrogen, sulfur or oxygen) The results of the thermogravimetric analysis (TGA) show higher weight loss of the modified silicas in comparison to the unmodified one. This indicates 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 that the trap density peak is not significantly shifted in temperature when the silica is modified with functional groups elementally similar to the polymer matrix. However, their incorporation influences the traps density and suppress the deeper traps occurring near the range of the melting temperature of PP. When the silica surface is modified with a precursor containing a hetero element, it has an effect on both, trap level depth as well as density. Depending on the type of the hetero element (sulfur, nitrogen, oxygen), the trap depth shifted to higher temperatures, and the trap density decreased to significantly lower levels. Nitrogen appears to have the strongest effect on the charge trap properties. All these first stage of results show that incorporation of modified nanosilica into a PP matrix seems to be a promising approach to tailor its electric properties. Further development of these composites would lead to benefits for high-voltage cable and capacitors applications.

AB - Novel nanocomposites for dielectric applications based on a polypropylene (PP) blend filled with nanosilica are developed in the frame of the European ‘GRIDABLE’ project. A systematic study of the influence of surface modification of the nanosilica on the dielectric properties of the PP/silica blend was performed. The main goal of this investigation was to modify the chemical composition of the silica surface, which is expected to improve 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. Eight different silanes were investigated in this study, which are categorized into three different groups: I)Aliphatic silanes with a different number of alkoxy groups II)Hydrocarbon silanes containing delocalized electron clouds III)Polar silanes containing hetero elements (nitrogen, sulfur or oxygen) The results of the thermogravimetric analysis (TGA) show higher weight loss of the modified silicas in comparison to the unmodified one. This indicates 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 that the trap density peak is not significantly shifted in temperature when the silica is modified with functional groups elementally similar to the polymer matrix. However, their incorporation influences the traps density and suppress the deeper traps occurring near the range of the melting temperature of PP. When the silica surface is modified with a precursor containing a hetero element, it has an effect on both, trap level depth as well as density. Depending on the type of the hetero element (sulfur, nitrogen, oxygen), the trap depth shifted to higher temperatures, and the trap density decreased to significantly lower levels. Nitrogen appears to have the strongest effect on the charge trap properties. All these first stage of results show that incorporation of modified nanosilica into a PP matrix seems to be a promising approach to tailor its electric properties. Further development of these composites would lead to benefits for high-voltage cable and capacitors applications.

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KW - dry silanization

KW - polypropylene dielectric nanocomposites

KW - charge trapping properties

KW - TSDC

KW - high voltage cable

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DO - 10.1109/ICEMPE.2019.8727244

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BT - 2nd International Conference on Electrical Materials and Power Equipment, ICEMPE 2019

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He X, Mahtabani A, Rytöluoto I, Saarimäki E, Lahti K, Paajanen M et al. Surface Modification of Fumed Silica by Dry Silanization for PP-based Dielectric Nanocomposites. In 2nd International Conference on Electrical Materials and Power Equipment, ICEMPE 2019. Institute of Electrical and Electronic Engineers IEEE. 2019. p. 254-259. 8727244 https://doi.org/10.1109/ICEMPE.2019.8727244