Fabrication and characterization of MWCNT/natural Azerbaijani bentonite electroconductive ceramic composites

Abstract

Multi-walled carbon nanotubes have been synthesized by Aerosol-Chemical Vapor Deposition method. Carbon nanotubes firstly have been used as filler in affordable and prevalent natural Azerbaijani bentonite clays for fabrication electroconductive ceramic composites. In this paper, multi-walled carbon nanotubes/natural Azerbaijani bentonite ceramic composites were prepared by two-factor mechanical method and followed by calcination at 1050℃ in an inert atmosphere. The ceramic composites were characterized by scanning electron microscope, atomic force microscope, X-ray diffraction and thermogravimetric-differential-thermal analysis. X-ray diffraction analysis confirmed the presence of two principal components – multi-walled carbon nanotube and bentonite in composites. From the thermogravimetric-differential-thermal data, it was revealed that multi-walled carbon nanotube/ bentonite ceramic composites demonstrate thermo-oxidative stability up to 580–640℃. Scanning electron microscope images demonstrated a sufficiently high dispersibility of carbon nanotubes and satisfactory homogeneity in the composites. Experimental results demonstrated that by increasing the mass fraction of multi-walled carbon nanotubes from 1% to 8% in multi-walled carbon nanotube/bentonite ceramic composites, the electrical conductivity enhances substantially. The enhancement of electrical conductivity of the composites explained the mass fraction of multi-walled carbon nanotubes, as well as the uniform dispersion of multi-walled carbon nanotubes in the bentonite clays. Compared with other 8% multi-walled carbon nanotubes/bentonite ceramic composites, the electrical conductivity of heptane-multi-walled carbon nanotube/Gobu bentonite (σ = 397 S·m−1) and heptane-multi-walled carbon nanotubes/Atyali (σ = 305 S·m−1) composites is 2–5 times higher than the conductivity of composites obtained with cyclohexane carbon nanotubes- cyclohexane-multi-walled carbon nanotube/Atyali (σ = 78 S·m−1), cyclohexane-multi-walled carbon nanotube/Gobu (σ = 111,5 S·m−1). These results can be explained with the structure, the number of layers, purity and diameter distribution, as well as the type and amount of defects in internal and external layers of Hep-multi-walled carbon nanotubes which cause better dispersion in bentonite clays. Due to the high conductivity and high temperature stability, these composites can be used as promising material for fabrication heating elements, electrodes, substrates for microelectronic devices, etc.

Natural Materials—Interesting Candidates for Carbon Nanomaterials

“…These results indicate the good mechanical stability of CNTs/bentonites composites. In 2018, Huseynov and colleagues used natural bentonite ceramic clays from the Atyali and Gobu deposits of Azerbaijan for MWCNTs' growth [67]. They employed the aerosol chemical vapor deposition technique with two types of carbon sources: cyclohexane-CyH (98%), and n-heptane-Hep (98%).…”

“…They neglected the role of Ni for CNT growth, considering the Ni content to be of a low amount. In the case of CNS growth, they speculated that initially some nanometer-sized catalyst chunks are coated with amorphous carbon, which in turn In 2018, Huseynov and colleagues used natural bentonite ceramic clays from the Atyali and Gobu deposits of Azerbaijan for MWCNTs' growth [67]. They employed the aerosol chemical vapor deposition technique with two types of carbon sources: cyclohexane-CyH (98%), and n-heptane-Hep (98%).…”

“…Ceramics reinforced with carbon nanomaterials have shown significant improvements in the areas of mechanical properties, high thermal stability, and high conductivity [90][91][92][93]. Huseynov and colleagues employed MWCNTS as electro-conductive ceramic composites [67]. Moreover, it was found that the incorporation of MWCNTs into the ceramic matrices can lead to a remarkable increment in electro-conductivity of MWCNT/bentonite ceramic composites, and the maximum value of electro-conductivity was found to be 8 wt% of MWCNTs.…”

Photoluminescent Carbon Dot-Intercalated Bentonite: A Light Responsive Nanohybrid for Lead Removal

“…selective adsorption, sensing, mechanical reinforcement). 1 Of relevance to the present work, bentonite clay was modified with carbon nanomaterials such as graphite, 2 graphene [3][4] and multiwalled carbon nanotubes [5][6] ; the resultant hybrid materials were widely used in renewable energy, electronics and environment remediation applications. The resulting hybrids combine both high surface area, adsorptive performance of the 2D nanoclays and high active sites, electric performance of carbon nanomaterials; this synergetic combination was expected to promote the performance of the targeted composites, especially in environmental domain.…”

Void characteristics and mechanical strength of cementitious mortars containing multi-walled carbon nanotubes

“…One of the most widely used nanomaterials in cementitious ingredients is carbon nanotube (CNT), which has attracted a lot of attention. [10][11][12][13][14][15][16] CNTs are used in the preparation of various materials due to their high specific surface area, small size, and hollow-layered structures. 17,18 By using CNTs in cementitious materials, the augmentation of mechanical properties has been reported in several studies.…”