Electrophysical Characteristics of Epoxy Nanocomposites with Ultralow Percolation Thresholds

摘要

Nanocomposites based on ED-20 epoxy resin and single-walled carbon nanotubes (SWCNT) with high aspect ratios (l/d ～ 2500) have been produced. The filler has been introduced into a matrix using a high speed mixer without solvents. The electrical and physical characteristics of produced composites have been examined at various SWCNT concentrations. A low percolation threshold is experimentally established, indicating weak filler agglomerates in the epoxy matrix. The dielectric permittivity and tangent loss are plotted as the functions of the SWCNT concentration within a wide frequency range. All dependences exhibit the presence of a relaxation peak shifting toward the higher frequencies as the filler concentration increases. The investigation of nanocompos-ite cleavages via scanning electron microscopy reveals a uniform SWCNT distribution in the matrix.