Carbon nanotube dispersion contains a liquid dispersion of carbon nanotubes treated.To synthesize carbon nanotubes resin composite material depends on the corresponding is waterborne resin or organic solvent resin. If it is a water-based resin, of course to use water-based carbon nanotube dispersion, if used in organic solvent resin, dispersion for alcohols.
Carbon nanotube resin composite material whether it is to do the conductive properties of modified or mechanical strength of resin composite material structure modification of carbon nanotubes, which needed to be cut to below 1:30 the ratio of length to diameter, will get better results, of course, the prerequisite is the tubular structure does not destroy the process must ensure that the cut in.
Carbonnanotubes are strong and flexible but very cohesive. They are difficult to disperse into liquids, such as water, ethanol, oil, polymer or epoxy resin. Ultrasound is an effective method to obtain discrete – single-dispersed – carbonnanotubes.Prior work on asymmetric thermally conductingnanoparticledispersions has shown that it is possible to raise the thermal conductivity of low thermal conductivityliquids at modest volume fractions of nanoparticles. Stable and reproducible nanotubedispersions require careful control of the dispersant chemistry as well as an understanding of their response to input energy. This paper addresses the effects of dispersant concentration, dispersing energy, and nanoparticle loading on thermal conductivity and steady shear viscosity of nanotube-in-oil dispersions. The thermal conductivity and viscosity of these dispersions correlate with each other and vary with the size of large scale agglomerates, or clustered nanoparticles, in the fluids. Fluids with large scale agglomerates have high thermal conductivities.Dispersion energy, applied by sonication, can decrease agglomerate size, but also breaks the nanotubes, decreasing both the thermal conductivity and viscosity of nanotubedispersions. Developing practical heat transfer fluids containing nanoparticles may require a balance between the thermal conductivity and viscosity of the dispersions.
CNT agglomerates, prepared by catalytic chemical vapor deposition in a nano-agglomerate fluidized-bed reactor are separated and dispersed. The effects of shearing, ball milling, and ultrasonic and chemical treatments on the dispersing of the carbon nanotubes were studied using SEM, TEM/HRTEM and a Malvern particle size analyser. The resulting microstructures of the agglomerates and the efficiency of the different dispersion methods are discussed. Representative results of annealed CNTs are highlighted. The as-prepared CNT product exists as loose multi-agglomerates, which can be separated by physical methods. Although a concentrated H2SO4/HNO3 (v/v=3:1) treatment is efficient in severing entangled nanotubes to enable their dispersion as individuals, damage to the tube-wall layers is serious and unavoidable. A high temperature annealing (2000 °C, 5 h) before the acid treatment (140 °C, 0.5 h) is recommended and can give well separated nanotubes with a high aspect ratio and 99.9% purity. These highly dispersed CNTs contain few impurities and minimal defects in their tube-bodies and will be of use in further research and applications.
CNTs Oil Dispersion are used in adhesives, coatings and polymers and as electrically conductive fillers in plastics to dissipate static charges in electrical equipment and in electrostatically paintable automobile body panels. By the use of nanotubes, polymers can be made more resistant against temperatures, harsh chemicals, corrosive environments, extreme pressures and abrasion. There are two categories of carbon nanotubes: Single-wall nanotubes (SWNT) and multi-wall nanotubes (MWNT).
Ultrasonic treatment is a simple and effective method to disperse carbon-nanotubes in water or organic solvents.Carbonnanotubes are generally available as dry material, e.g. from companies, such as SES Research or CNT Co., Ltd. A simple, reliable and scalable process for deagglomeration is needed, in order to utilize the nanotubes to their maximum potential. For liquids of up to 100,000cP ultrasound is a very effective technology for the dispersing of nanotubes in water, oil or polymers at low or high concentrations. The liquid jet streams resulting from ultrasonic cavitation, overcome the bonding forces between the nanotubes, and separate the tubes. Because of the ultrasonically generated shear forces and micro turbulences ultrasound can assist in the surface coating and chemical reaction of nanotubes with other materials, too.
Ultrasonication is a an effective procedure to untangle carbonnanotubes in water or organic solvents.Generally, a coarse nanotube-dispersion is first premixed by a standard stirrer and then homogenized in the ultrasonic flow cell reactor. The video below (Click image to start!) shows a lab trial (batch sonication using a UP400S) dispersing multiwall carbonnanotubes in water at low concentration. Because of the chemical nature of carbon the dispersing behavior of nanotubes in water is rather difficult. As shown in the video, it can be easily demonstrated that ultrasonication is capable to disperse nanotubes effectively.
As a result, the SWNTs are typically dispersed as bundles rather than fully isolated individual objects. When too harsh conditions are employed during dispersion, the SWNTs are shortened to lengths between 80 and 200nm. Although this is useful for certain tests, this length is too small for most practical applications, such as semiconducting or reinforcing SWNTs. Controlled, mild ultrasonic treatment (e.g. by UP200Ht with 40mm sonotrode) is a effective procedure to prepare aqueous dispersions of long individual SWNTs. Sequences of mild ultrasonication minimize the shortening and allow maximal preservation of structural and electronic properties.
