Key Words:Electric conductivity of solids;Aliphatic compounds - Alumina - Aluminum oxide - Aspect ratio - Blending - Carrier mobility - Electric breakdown - Electric properties - Electric space charge - Electric variables measurement - Nanocomposites - Nanosheets - Polyethylenes
Abstract:This paper describes the effects of α-Al<inf>2</inf>O<inf>3</inf> nanosheets on the direct current voltage breakdown strength and space charge accumulation in crosslinked polyethylene/α-Al<inf>2</inf>O<inf>3</inf> nanocomposites. The α-Al<inf>2</inf>O<inf>3</inf> nanosheets with a uniform size and high aspect ratio were synthesized, surface-modified, and characterized. The α-Al<inf>2</inf>O<inf>3</inf> nanosheets were uniformly distributed into a crosslinked polyethylene matrix by mechanical blending and hot-press crosslinking. Direct current breakdown testing, electrical conductivity tests, and measurements of space charge indicated that the addition of α-Al<inf>2</inf>O<inf>3</inf> nanosheets introduced a large number of deep traps, blocked the charge injection, and decreased the charge carrier mobility, thereby significantly reducing the conductivity (from 3.25 x 10<sup>-13</sup> S/m to 1.04 x 10<sup>-13</sup> S/m), improving the direct current breakdown strength (from 220 to 320 kV/mm) and suppressing the space charge accumulation in the crosslinked polyethylene matrix. Besides, the results of direct current breakdown testing and electrical conductivity tests also showed that the surface modification of α-Al<inf>2</inf>O<inf>3</inf> nanosheets effectively improved the direct current breakdown strength and reduced the conductivity of crosslinked polyethylene/α-Al<inf>2</inf>O<inf>3</inf> nanocomposites.<br/> © 2020 by the authors.
Volume:13
Issue:6
Translation or Not:no