On the Silica Surface Modification and Its Effect on Charge Trapping and Transport in PP-Based Dielectric Nanocomposites

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

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

61 Citations (Scopus)
139 Downloads (Pure)

Abstract

The effect of filler surface functionalization with 3-aminopropyltriethoxysilane (APTES) on the charge trapping and transport was studied in polypropylene (PP)/(ethylene-octene) copolymer (EOC)/silica nanodielectrics. Different reaction conditions were utilized for silica functionalization to alter the deposited layer morphology. This approach made it possible to engineer the filler-polymer interface to achieve optimized dielectric properties for the nanocomposites. The successful chemical modification of the silica surface was confirmed via thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Subsequently, the effect of the engineered filler-polymer interface on the nanocomposites’ crystallinity was analyzed with differential scanning calorimetry (DSC). Scanning electron microscopy (SEM) was utilized to observe the morphology of the nanocomposite as well as the silica dispersion. Finally, the effect of the silica functionalization on the dielectric properties of PP/EOC/silica nanocomposites was tested via thermally stimulated depolarization current (TSDC) and broadband dielectric spectroscopy (BDS). The results suggested that the presence of the amine functionality on the silica reduces interfacial losses in nanocomposites, and hinders further injection of space charge by introducing deep trap states at the filler-polymer interface. Under certain conditions, APTES can form an “island-like” morphology on the silica surface. These islands can facilitate nucleation, inducing transcrystallization at the filler-polymer interface. The island-like structures present on the silica would further contribute to the induction of deep traps at the filler-polymer interface resulting in the reduction of space charge injection.

Original languageEnglish
Pages (from-to)3148-3160
Number of pages13
JournalACS Applied Polymer Materials
Volume2
Issue number8
Early online date22 Jul 2020
DOIs
Publication statusPublished - 14 Aug 2020

Keywords

  • dielectric properties
  • HVDC
  • PP-based nanodielectrics
  • silica surface modification
  • space charge
  • TSDC
  • UT-Hybrid-D

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