Carbon black agglomerates

Rumscheidt, F. D., and Mason, S. G., Particle motions in sheared suspensions. XII. Deformation and burst of fluid drops in shear and hyperbolic flow. J. ColloidScL 16,238-261 (1961). Rwei, S. P., Manas-Zloczower, I., and Feke, D. L., Observation of carbon black agglomerate dispersion in simple shear flows. Polym. Eng. ScL 30, 701-706 (1990). 

Studies on the kinetics of carbon black dispersion in various rubbers have been reported using a Brabender mixer fitted with cam-type rotors [110]. Dispersion rating, determined by visual inspection of photomicrographs, was found to depend strongly on mixing time. For an SBR emulsion, it was observed that there was an initial delay period where the carbon black agglomerates were thought to be fractured and incorporated into the rubber. Subsequently, the process of dispersion continued for a considerable time thereafter. 

Example 7.4 The Strength of Carbon Black Agglomerates Calculate the tensile... 

Fig. 7.27 Rupture time sequence of a carbon black agglomerate (R0 = 30 pm) in a styrene-cobutadiene rubber (SBR) in simple shear flow. The shear rate was 13.5 s 1 resulting in a shear stress of 130,000 Pa. [Reprinted by permission from V. Collin, Etude Rheo-optique des Mecanismes de Dispersion du Noir de Carbone dans des Elastomeres, Doctoral Dissertation, Ecole des Mines de Paris, Sophia, Antipolis, France (2004).]...

Example 7.5 The Shear Stresses Needed to Break 100 pm Diameter Spherical Carbon Black Agglomerates having Tensile Strengths given in Example 7.4. 

Roll-mill for Dispersive Mixing A laboratory roll-mill with 5-in diameter rolls and 0.05 in minimum clearance between the rolls is used for dispersive mixing of carbon black agglomerates in LDPE. Calculate the roll speed needed to break up 5 of the particles per pass, assuming that the critical shear stress needed for breakup is that obtained in Problem 7.12 in the narrow clearance, and that the amount of polymer on the rolls is 50% above the minimum. Assume the same constant viscosity as in Problem 7.7. 

Figure 4.13 Dispersion rate of carbon black agglomerates in a PE melt depending on the shear stress and stress duration (trials with a single screw extruder) [17]...

In this specific model, approximately the same number of chains connect the cores directly ( fixed length chains ) as they do through carbon black agglomerates, and at zero time, 2(1 /Nt) = 2.12 10-2 and m/p = 0.02. Initially, therefore, fire load is more or less equally divided between the two groups of molecules. In a relaxation experiment, when Yd reaches a value of 60 1020,2(1 /TV,-) = 0.833 10-2, and the chains of constant length can therefore be calculated as carrying about 71%... 

The dispersion of carbon black agglomerates which are in suspension of liquid polymethylsiloxane and their dependence fi om the shear stress, has been studied by simple shear flow in cone-and-plate shearing device [13, 14]. The statements presented above show that the results of the research on the influence of mixing duration on the dispersing degree of the carbon black... 

Shiga, S. and Fumta, M. (1985) Processability of EPR in an internal mixer (II) morphological changes of carbon black agglomerates during mixing. Rubber Chem. Technol., 58, 1. 

Figure 4. Average size distribution of carbon black agglomerates with various...

The distributive and dispersive mixing based on the flow field is evaluated experimentally in this article. This study began by considering the dispersive mixing in terms of size distribution of carbon black agglomerates with different volume fraction of the materials. 

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