Polyethylene nanocomposite dielectrics: Implications of nanofiller orientation on high field properties and energy storage

Abstract

Nanocomposite formation, through the incorporation of high aspect ratio nanoparticles, has been proven to enhance the dielectric properties of thermoplastic polymers, when the mitigation of internal charges and the nature of the interfacial regions are properly adjusted. Here, we explore polyethylene/montmorillonite nanocomposites, and we specifically investigate how to impart desirable dielectric behavior through controlled nanoscale texturing, i.e., through control of the spatial arrangement of the high aspect ratio nanofiller platelets. In particular, it is shown that filler alignment can be used to improve the high electric-field breakdown strength and the recoverable energy density. The origins of the improved high field performance were traced to improved charge-trapping by a synergy of nanofillers and polar maleic anhydride (MAH) groups—introduced via polyethylene-MAH copolymers—as templated by the inorganic nanofillers. Further, it is conclusively demonstrated that the alignment of the two-dimensional nanoparticles has a measurable positive effect on the breakdown strength of the materials and, consequently, on the maximum recoverable energy density.

Dielectric investigation of high density polyethylene loaded by ZnO nanoparticles synthesized by sol–gel route

“…Here, the polarizations are associated with HDPE matrix, ZnO NPs and HDPE-NPs interfaces while the nonpolar nature of HDPE may have the dominant effect on the small dielectric response at the applied range of frequency. The same behavior has been previously observed for polyethylene nanocomposites [31,32].…”

Ultrahigh Energy Density of Polymer Nanocomposites Containing BaTiO3@TiO2 Nanofibers by Atomic‐Scale Interface Engineering

“…However, increased ε r is usually achieved at the cost of substantially decreased E B , as a result of the structural imperfections caused by the high loading of ceramics nanoparticles and more importantly, due to the large contrast in permittivity between the ceramic nano particles and the polymer matrix that induces signifi cant electric fi eld concentration in the polymer and results in a dramatically decreased breakdown strength of polymer nanocomposites. Compromises have thus been made by replacing the high-ε r nanoparticles with fi llers of large aspect ratios, such as TiO 2 , [ 9 ] BaTiO 3 nanofi bers (1D) [ 10 ] or montmorillonite, [ 11 ] clay nanosheets (2D). [ 12 ] The enhanced E B of these nanocomposites could be attributed to the ordered traps, more scattering centers to injected charges and increased path tortuosity in the electrical treeing process during breakdown.…”

The effect of mechanical relaxation on ultra-fast charge pulses in flexible epoxy resin nanocomposites

“…The generation and transport of ultra-fast pulses are considered to be governed by the chain relaxation and mechanical properties of the polymer rather than by hopping through localized states (traps), which implies a brand new conduction mechanism related to electromechanical compression in polymers. The introduction of nanofillers into a polymer provides a method to modify the mechanical, magnetic, electric and optical properties of the polymer itself [10][11][12]. Therefore, if the characteristics of the fast pulses change together with the mechanical relaxation of a nanostructured polymeric material, showing a correlation with the presence and concentration of nanoparticles, which would be strong support for the former explanation regarding the conduction mechanism associated with fast pulses [8,9,13].…”