Coupled thermal‐electrical analysis of carbon nanotube/epoxy composites

Abstract

The electrical and thermal behavior of epoxy composites reinforced with different contents of multi‐walled carbon nanotubes (from 0.1 to 0.4 wt% CNT) is studied when they are subjected to relatively high DC voltages (from 1 to 100 V). These materials obey Ohm's law, reaching values of electrical conductivity in the range of 0.01–0.5 S/m. The transported electric current leads to a significant increase of temperature, which is a result of the Joule heating effect. The temperature increases to 40ºC in CNT/epoxy composites when applying 100 V. The study of heating due to Joule's effect gives information about the electrical transport mechanisms implied. It is also confirmed that both, electrical conductivity and Joule's heating effect depend on the morphological features of the composites. The functionalization of CNTs decreases the electrical conductivity of composites but increases their corresponding Joule heating, due to the strong interface between the nanotubes and matrix, which hinders the formation of pathways in CNT in direct contact. The technique of CNT dispersion applied also affects to the increase of temperature induced by the electrical current. POLYM. ENG. SCI., 54:1976–1982, 2014. © 2013 Society of Plastics Engineers

Simulation of self-heating process on the nanoscale: a multiscale approach for molecular models of nanocomposite materials

“…This gap between the region below and above the percolation threshold is in agreement with the experiments, and with the fact that the formation of a percolative conductive network causes a neat transition of the system from insulator to conductor. 56,100 As general trend we nd that the heating rate increases as the applied voltage is higher for all the investigated CNT concentrations. In particular, from 3 to 10% of CNT, the sensitivity to the external voltage increases drastically, indeed while for a CNT concentration of 3% the heating rate does not overcome 1 C s À1 even when an external voltage of 100 V is applied, while for a concentration of 10% the heating rate jumps from about 4 C s À1 at 25 V to about 64 C s À1 when 100 V are applied to the system.…”

Dielectric and Electrical Properties of WS2 Nanotubes/Epoxy Composites and Their Use for Stress Monitoring of Structures

“…For the electrically conducting samples 8-11 (25 Vol.% nanotubes) the Nyquist plots ( Figure 6(b)) almost complete an ideal semicircle. It was observed that sample 8 (prepared under pressure of 0.8 MPa) presents the smallest resistive element among the studied conducting samples (8)(9)(10)(11), which agrees with the DC current measurements (see Table 1). At the high frequencies the specimen response is dominated by the capacity of the nanotubes, while at the low frequencies range the response reflects mostly the contribution from the high resistance of the polymer [39].…”

“…of the compressed pure INT-WS 2 exhibited a semiconducting behavior of the nanotubes (Figure 8(a)) [25] with the estimated band gap of 1.5-2 V. In addition, the I-U test demonstrated a remarkable difference between the DC conductivity of samples (8)(9)(10)(11) compared to that of the neat epoxy ( Supplementary Information Fig. S8) and the pure INT pellet (Figure 8).…”

“…The interest for incorporating nanoparticles in polymers has grown in the last two decades. Various nanofillers offer wide range of properties such as mechanical [4], thermal [5], and electrical [6] conductivities and may be successfully introduced into polymers [7][8][9][10]. Since their discovery, carbon nanotubes (CNTs) [11,12] were investigated intensively and a wide range of applications were offered to various devices based on CNTs.…”

Multifunctionalized Carbon Nanotubes Polymer Composites: Properties and Applications

“…CNT's electrical conductivity-filled epoxy nanocomposites, with less than 0.5 wt % of CNTs, were improved by several orders of magnitude (Jiang et al 2013a, b;Russ et al 2013;Prolongo et al 2013, He et al 2013Safdari and Al-Haik 2013). Furthermore, thermal conductivity of epoxy matrix at room temperature increased by 300 % on 3 wt% SWCNTs loading, and an additional increase of 10 % once they are magnetically aligned (Li et al 2013a, b, c, d, e).…”