Influence of carbon nanotube surface treatment on resistivity and low‐frequency noise characteristics of epoxy‐based composites

Abstract

Resistivity and low‐frequency (10 Hz–20 kHz) noise characteristics of composite materials with multi‐walled carbon nanotubes (MWCNTs) of different surface treatment, that is, MWCNTs covered with bisphenol‐A based liquid epoxy resin (epoxy‐grafted) and polyethylene polyamine (amino‐grafted), have been carried out over the temperature range from 73 to 380 K. The resistivity of the investigated materials decreases with temperature increase up to 250 K; at higher temperatures polymer matrix expansion leads to the resistivity increase and above 340 K the conductivity in the matrix becomes significant. Low‐frequency noise spectra of the investigated materials are 1/fα‐type and noise spectral density is proportional to the squared voltage. The observed fluctuations in the investigated materials are resistance fluctuations. The conduction in the investigated composites is caused by tunneling inside and between MWCNTs controlled by charge carrier capture and release processes in localized states. MWCNT's surface treatment by polyethylene polyamine leads to the larger density of surface states what causes lower resistivity and more intensive low‐frequency fluctuations. POLYM. COMPOS., 39:E1224–E1230, 2018. © 2018 Society of Plastics Engineers

Noise and Electrical Characteristics of Composites Filled with Onion-Like Carbon Nanoparticles

“…These defects form charge carrier trapping centers with widely distributed characteristic times, and the processes of capture and release of charge carriers through these centers are well reflected in the low-frequency noise characteristics. The voltage noise spectra of the materials investigated at room temperature are 1/f α –type, where varies between 0.68 and 1.45 for different spectra ( Figure 8 ), which is characteristic of the superposition of the processes of capture and release of charge carriers by the trapping centers with widely distributed characteristic times [ 37 , 41 , 49 , 51 ].…”

“…One of the most sensitive methods for analyzing charge transfer mechanisms in composite materials is the study of low-frequency noise, which allows the smallest fluctuation in the physical processes occurring in the material to be captured [ 35 , 36 , 37 , 38 ]. There are very few papers on the noise characteristics of carbon nanoparticle-based composite materials [ 35 , 39 ], although noise studies can highlight the influence of the type of carbon nanofiller on the charge transfer mechanisms [ 40 , 41 ]. In this paper, we present an in-depth study of the electrical and low-frequency noise characteristics of composite materials where onion-like carbon particles of different sizes have been used as conductive fillers in an epoxy resin.…”

High resistivity‐temperature effect of resistivity for economical and facile conductive polymer composites with low percolation threshold via self‐constructed dual continuous structure

“…[1][2][3][4][5][6][7][8][9][10][11] Especially, numerous conductive polymer materials were comprehensively applied in 5G electronics in recent years. The CPCs usually comprised the polymer matrix and electrically conductive fillers including metal fillers, 12,13 carbon black (CB), [14][15][16] carbon nanotube (CNT), [17][18][19][20] carbon fiber (CF), 21 graphene and graphite. [22][23][24][25][26] The electrically conductive properties of the composites generally depended on the conductive characteristics and dispersion of fillers, the microstructure of the composites, processing method, and so on.…”

Economical conductive graphite‐filled polymer composites via adjustable segregated structures: Construction, low percolation threshold, and positive temperature coefficient effect

“…However, so far CPCs still had several disadvantages. On one hand, the fillers with high conductivity were relatively high costs, such as carbon nanotubes (CNTs), [16][17][18][19] graphene, 20,21 and metal fillers. On the other hand, high electrical conductivity for CPCs generally meant high contents of fillers.…”