Abstract
AbstractThis is the first broadband dielectric spectroscopy study on the temperature- and frequency-dependent electrical conductivity of polyamide 6 (PA6) composites containing both metal microparticles (Al, Fe, or Cu) and carbon nanotubes (CNT). The dually reinforced PA6 hybrids are prepared through compression molding of metal- and CNT-loaded microparticles (MP). These MP are synthesized by activated anionic ring-opening polymerization (AAROP) of ε-caprolactam in suspension, carried out in the presence of the micron-sized metal powders and the nanosized CNT fillers, with a combined load of up to 10 wt%. The good dispersion of the two loads by the AAROP strategy results in a notable increase in the electrical conductivity by up to 11 orders of magnitude. Moreover, the frequency-dependent behavior of the measured conductivity obeys the so-called universal dynamic response. This response involves a direct current (d.c.) electrical conductivity ($${\sigma }_{{\text{dc}}}$$
σ
dc
) observed beyond a critical frequency, $${F}_{{\text{c}}}$$
F
c
, followed by a power-law response characterized by an exponent s, which fluctuates between 0.11 and 0.43. The $${\sigma }_{{\text{dc}}}$$
σ
dc
of the binary composites spans from 1.42 $$\times$$
×
10−5 to 1.63 $$\times$$
×
10−2 S/cm, this increase being attributed to the synergetic effect between CNT and the metal particles that contribute to the carrier mobility within the conductive network.
Graphical Abstract
Funder
Fundação para a Ciência e a Tecnologia
Ministerio de Ciencia e Innovación
Universidade do Minho
Publisher
Springer Science and Business Media LLC
Subject
Mechanical Engineering,Mechanics of Materials,General Materials Science