Carbon black transmission electron microscopy

FIGURE 22.1 Transmission electron microscopy (TEM) micrograph of a carbon black network obtained from an ultrathin cut of a filled rubber sample. 

Fig. 3.2 HRTEM (high resolution transmission electron microscopy) image of a furnace carbon black. Curved graphene sheets and surfaces can be easily observed...

For the first time, TIRE-LII has been successfully applied to the characterization of in liquids suspended nanoparticles. Re-dispersed carbon blacks were investigated in different solvents, whereby a linear correlation between the exponential LII signal decay time and the primary particle size determined by transmission-electron microscopy was found. 

A mixture of boric acid (1 g) and urea (11.8 g) was taken in 40 ml distilled water and heated at 70 °C until the solution became viscous the a-CNTs were soaked in it for nearly 2 h. They were later separated physically and dried in air at 40 C overnight. The dried sample was thermally treated at 970 °C for 3 h for 40 nm nanotubes in a N2 atmosphere, and for 12 h in the case of the larger diameter (170 nm) nanotubes, and then cooled down to room temperature. The product was subsequently heated in an NHt atmosphere at 1050 °C in case of 170 nm nanotubes and 900 C in case of 40 nm nanotubes for three hours to give black-coloured boron-carbon-nitride nanotube brushes. The products were investigated by transmission electron microscopy and other physical techniques. 

Scanning electron microscopy (SEM) data for carbon-black compounds and conductive polymer blends [72c], supported by recent transmission electron microscopy (TEM) evaluations [79,80] (shown in Figure 11.39) were made, they also contradict the assumption of a statistical distribution. We find complete dispersion below the critical volume concentration (I) and a sudden stiucture formation ( branched flocculate chains ) at the critical volume concentration. This structural feature remains at higher concentrations. 

It is important to emphasize that the actual morphology of carbon blacks has remained unknown for decades, even if it was commonly used in the rubber industry. This is due to the very small size of its constituting objects they are smaller than 0.1 tim and can only be resolved by transmission electron microscopy. 

As observed by transmission electron microscopy, carbon blacks appear as irregular, chainlike, branched aggregates of partially fused spheres (Hess et al., 1973). 

As evidenced by transmission electron microscopy (Hess, 1991 Herd et al., 1992), surface area is directly linked to the size of primary particles so that American Society of Testing Materials (ASTM) has chosen this parameter for carbon black nomenclature. More precisely, ASTM nomenclature includes four digits, the first one relates to vulcanization speed (N as normal or S as slow), then tree numbers, which first correspond to the primary particle diameter. 

Transmission electron microscopy/image analysis (TEM/AI) has been used for a long time to determine aggregate size distribution of carbon black and silicas (Goritz et al, 1997). Such studies are very costly because they need at least a few thousand aggregate size measurements to determine precisely the size distribution. Nevertheless, using TEM/AI aggregates are measured as two-dimensional projections, which probably maximizes their sizes. 

Performance of rubber compounds is affected by micromorphology, such as polymer compatibility and carbon black distribution. Transmission electron microscopy has been commonly used to examine micromorphology. More recently, atomic force microscopy, also referred to as scanning probe microscopy, has been used for this purpose. Tapping mode atomic force microscopy can be used to distinguish two different polymer domains in unfilled rubber... 

Zhang et al. [63] prepared styrene-butadiene nanocomposites by dispersing an aqueous dispersion of montmoril-lonite and latex and flocculating the dispersion with acid. The performance of the rubber nanocomposites were compared with clay, carbon black, and silica rubber composites prepared by standard compotmding methods. The montmoriUonite loadings for the rubber nanocomposite were up to 60 phr. The morphology of the rubber nanocomposites by transmission electron microscopy appears to indicate intercalated structures. The mechanical properties of the rubber nanocomposites were superior to all of the other additives up to about 30 phr. However, rebound resistance was inferior to all of the additives except sUica. The state of cure was not evaluated. 

Liu, Z.Y., Zhang, J.L, Yu, P.T., Zhang, J.X., Makharia, R., More, K.L., and Stach, E.A. (2010) Transmission electron microscopy observation of corrosion behaviors of platinized carbon blacks under thermal and electrochemical conditions. J. Electrochem. Soc., 157, B906-B913. 

The classification scheme shown is not definite. For example, the distinction between NPs and clusters cannot be established on the basis of dimensional criteria. Although the term cluster is used for small Au NPs [34], in principle, they are characterized by a well-defined structure [35], while the mobility of the surface atoms in the NPs does not allow one to ascribe them an exact geometrical shape. Similarly, although transmission electron microscopy (TEM) images depict carbon black particles as spherical and they are thus classified as OD nano-objects, they actually consist of disordered graphene sheets. 

Fig. 6.2 Carbon-based materials used in electroanalysis schemes for (a) single- and (b) multiwall carbon nanotubes, (c) graphene, (d) C o fullerene (e) transmission electron microscopy images of carbon black particles (Reproduced from Refs. [45,54,55], and [56] with the permission of Springer, American Chemical Society and InTech, respectively)...

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