Carbon black content

Reinforcing fillers in general and high-structure carbon blacks in particular improve the extrusion characteristics of elastomers by decreasing extrudate swell. The extrudate swell decreases with increasing carbon black content [33]. 

Today, highly loaded silica compounds with relatively low carbon black content for tread profiles are becoming the standard for high-tech PCR tires. 

The physical network chain density (nent) was estimated from the comparison of the NMR and swelling results. A linear relationship of the nent in the NR system as a function of carbon black content exists. This result suggests that the physical adsorption plays a major role in the polymer-filler interactions. 

Figure 9.11 Physical network chain densities of NR cure to t9() with a variety of carbon black as a function of carbon-black content...

The new resonances, which appear with vulcanisation in the presence of carbon black, are qualitatively the same as observed for the unfilled formulation systems, i.e., new resonances at 50.7, 50.2, and 37 ppm were detected at lower cure times. At longer cure times these three resonances disappeared and new resonances were detected at 58, 64, and 45 ppm along with new peaks at 17 and 12 ppm and the growing of the intensity of the peak at 14 ppm. As the amount of carbon black content increased, the latter features were observed at an earlier stage of cure. 

Fig. 8.12 The dependence of the conductivity of a polyethylene furnace black composite on carbon-black content. Reprinted from Hindermann-Bischoff and Ehrburger-Dolle (2001). Copyright 2001, with permission from Elsevier.

Fig. 8.14 Comparison of the experimental and theoretical dependences of resistivity on carbon-black content iaa polyethylene composite. Reproduced with permission of the Institute of Physics from Scarisbrick (1973).

The final pigment black concentration to produce a good opacity is 2-5%, for base coats up to 10%, calculated on resin solid. Pigment blacks with extremely high-structure and surface area can be used for electro-conductive coatings [4.27, 4.29]. The carbon black content in this case is 30-50% on resin solid. 

There are a large variety of E-SBR types based on the styrene content, polymerization temperature, antioxidants, oil and carbon black content. Each of these basic classifications includes a variety of SBR polymer variations with respect to Mooney viscosities, coagulation types, emulsifier type, oil levels, and carbon black types and levels. Table 2 shows the basic series of E-SBR. 

Applications Gas chromatography has limited applications to filled systems. It was used for characterization of the various degradation products of ethylene ethyl acrylate copolymer filled with calcium carbonate by GC-MS, " evaluation of ecotoxi-cological properties of materials containing flame retardants,"" and determination of carbon black content by pyrolysis gas chromatography." ... 

Figure 16.7. Resistivity vs. carbon black content in a PE/PS blend, depending on annealing regime. [Adapted, by permission, from Gubbels F, Blacher S, Vanlathem E, Jerome R, Deltour R, Brouers F, Teyssie Ph, Macromolecules, 28, No.5, 1995, 1559-66.]...

Fig. 7.1.13 Calibration curves of relaxation times versus temperature for filled SBR samples, (a) T2 for samples with different carbon-black content. The straight lines are fits to the experimental data, (b) T[ for SBR filled with SOphr carbon black. Adapted from [Haul] with permission from Wiley-VCH.

For carbon-black filled SBR, T2 is directly proportional to temperature. Thus, a T2-parameter image corresponds to a temperature image of the sample. Axial parameter projections have been acquired in dynamic equilibrium at a shear rate of 10 Hz, and a pixel resolution of 0.4 x 0.4 mm, for SBR cylinders with carbon-black contents ranging from 0-50 phr. ID cross-sections through those projections are depicted in Fig. 5.12. An increase of temperature in the center of the sample is observed with increasing carbon-... 

These measurements were performed on the pipe samples as such, on the pipe samples after machining away the 0.3 mm. thick outside resin layer and finally after machining away a layer of 2.3 mm. Small sample disks (diameter 5 mm.) were taken out of the liner layer, the pipe body and the outside resin layer, to determine the carbon black content by TGA analysis. Some relevant results are listed in Table 5.7 and plotted in Figure 5.27. 

NECO, NEC3, NEC5, NEC7, NECIO, NEC20, and NEC30 are 70 30 NR/EPDM blends with carbon black content 0, 3, 5, 7, 10, 20, and 30 phr, respectively, b—the resistivities were lower than the limit of the testing equipment. 

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