Dielectric response of structured multilayered polymer films fabricated by forced assembly

Abstract

The effect of introducing a multilayer microstructure on the dielectric properties of polymer materials is evaluated in 32- and 256-layer films with alternating polycarbonate (PC) and polyvinylidene-hexafluoropropylene (coPVDF) layers. The permittivity, dielectric loss, dielectric strength, and energy density were measured as a function of the relative PC/coPVDF volume concentrations. The permittivity follows an effective medium model while the dielectric strength was typically higher than that predicted by a volume fraction based weighted average of the components. Energy densities as high as ∼14J∕cm3, about 60% greater than that of the component polymers, are measured for 50% PC/50% coPVDF films.

Space charge dynamics at the physical interface in oil-paper insulation under DC voltage

“…This differs significantly from the results in [22][23]. In [22][23], the interface served as a trapping site, allowing the passage of positive charge and to a lesser extent, negative charge [24], and it was the same with the results in [4]. This phenomenon is thought to be determined by the nature of surface states and electrodes in [4], while the formation of an electrical double layer in this experiment signified that there were other reasons.…”

“…This differs significantly from the results in [22][23]. In [22][23], the interface served as a trapping site, allowing the passage of positive charge and to a lesser extent, negative charge [24], and it was the same with the results in [4].…”

The effect of strain-hardening on the morphology and mechanical and dielectric properties of multi-layered PP foam/PP film

“…Therefore, it is important to optimize the rheological properties of the PP resins in order to deliver good foam products, with well-controlled cell type, size and density. Finally, the continuous microlayer co-extrusion technique has yielded improved mechanical, optical, transport, and dielectric properties of polymeric materials in layered structures by increasing the number of layers [29][30][31][32]. This technique can also lead to better morphology of PP/PP foam via the layer confinement that the PP film layers provide and suppress the growth of the PP foam layers, resulting in smaller cell sizes and narrow cell size distribution.…”

“…Three complementary approaches are possible in order to obtain a microcellular PP foam/film with improved foaming behavior and morphology that can mimic that of cork: the use of a nucleating agent, the incorporation of long chain branches, and processing via continuous microlayer co-extrusion [19][20][21][22][23][24][25][26][27][28][29][30][31][32]. A nucleating agent is helpful to nucleate and crystallize polypropylene earlier in the cooling process at a faster rate [20][21][22][23].…”

“…Schematics of (a) 2-component multilayer co-extrusion system and (b) schematic diagram of doubling layers through layer multiplier [19,32]. tests.…”