TY  - JOUR
A1  - He, Yushuang
A1  - Wang, Feipeng
A1  - He, Li
A1  - Wang, Qiang
A1  - Li, Jian
A1  - Qian, Yihua
A1  - Gerhard, Reimund
A1  - Plath, Ronald
T1  - An insight Into the role of Nano-Alumina on DC Flashover-Resistance and surface charge variation of Epoxy Nanocomposites
JF  - IEEE transactions on dielectrics and electrical insulation
N2  - The addition of nano-Al2O3 has been shown to enhance the breakdown voltage of epoxy resin, but its flashover results appeared with disputation. This work concentrates on the surface charge variation and dc flashover performance of epoxy resin with nano-Al2O3 doping. The dispersion of nano-Al2O3 in epoxy is characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The dc flashover voltages of samples under either positive or negative polarity are measured with a finger-electrode system, and the surface charge variations before and after flashovers were identified from the surface potential mapping. The results evidence that nano-Al2O3 would lead to a 16.9% voltage drop for the negative flashovers and a 6.8% drop for positive cases. It is found that one-time flashover clears most of the accumulated surface charges, regardless of positive or negative. As a result, the ground electrode is neighbored by an equipotential zone enclosed with low-density heterocharges. The equipotential zone tends to be broadened after 20 flashovers. The nano-Al2O3 is noticed as beneficial to downsize the equipotential zone due to its capability on charge migration, which is reasonable to maintain flashover voltage at a high level after multiple flashovers. Hence, nano-Al2O3 plays a significant role in improving epoxy with high resistance to multiple flashovers.
KW  - surface morphology
KW  - Epoxy resins
KW  - Electric potential
KW  - Surface treatment
KW  - Doping
KW  - Epoxy resin
KW  - multiple
KW  - flashover
KW  - nanocomposite
KW  - surface charge
Y1  - 2022
U6  - https://doi.org/10.1109/TDEI.2022.3173510
SN  - 1070-9878
SN  - 1558-4135
VL  - 29
IS  - 3
SP  - 1022
EP  - 1029
PB  - Inst. of Electr. and Electronics Engineers
CY  - Piscataway
ER  - 
TY  - JOUR
A1  - Kofod, Guggi
A1  - Risse, Sebastian
A1  - Stoyanov, Hristiyan
A1  - McCarthy, Denis N.
A1  - Sokolov, Sergey
A1  - Krähnert, Ralph
T1  - Broad-spectrum enhancement of polymer composite dielectric constant at ultra low volume fractions of silica-supported copper nanoparticles
JF  - ACS nano
N2  - A new strategy for the synthesis of high permittivity polymer composites is demonstrated based on well-defined spatial distribution of ultralow amounts of conductive nanoparticles. The spatial distribution Was realized by immobilizing Cu nanoparticles within the pore system of Alia microspheres, preventing direct contact between individual Cu particles. Both Cu-loaded and unloaded silica microspheres were-then used as fillers in polymer composites prepared with thermoplastic SEBS rubber is the matrix. With a metallic Cu content of about 0.26 vol % In the compoilte, a relative increase of 94% In real permittivity was obtained. No Cu-induced relaxations were observed in the dielectric spectrum within the studied frequency range of 0.1 Hz to 1 MHz. When related to the amount of conductive nanoparticles, the obtained composites achieve the highest broad spectrum enhancement of permittivity ever reported for a polymer based composite.
KW  - nanocomposite
KW  - broad-spectrum permittivity enhancement
KW  - metal nanoparticles
KW  - uniform spatial arrangement
Y1  - 2011
U6  - https://doi.org/10.1021/nn103097q
SN  - 1936-0851
VL  - 5
IS  - 3
SP  - 1623
EP  - 1629
PB  - American Chemical Society
CY  - Washington
ER  -