Kinetics clusters

Flocculation studies, considering the small-strain mechanical response of the uncross-hnked composites during heat treatment (annealing), demonstrate that a relative movement of the particles takes place that depends on particle size, molar mass of the polymer, as well as polymer-filler and filler-filler interactions (Figure 22.2). This provides strong experimental evidence for a kinetic cluster-cluster aggregation (CCA) mechanism of filler particles in the mbber matrix to form a filler network [24]. 

The CCA-model considers the filler network as a result of kinetically cluster-cluster-aggregation, where the size of the fractal network heterogeneity is given by a space-filling condition for the filler clusters [60,63,64,92]. We will summarize the basic assumptions of this approach and extend it by adding additional considerations as well as experimental results. Thereby, we will apply the CCA-model to rubber composites filled with carbon black as well as polymeric filler particles (microgels) of spherical shape and almost mono-disperse size distribution that allow for a better understanding of the mechanisms of rubber reinforcement. 

Kolb, M. Unified description of static and dynamic scaling for kinetic cluster formation. Phys. Rev. Lett., 1984,53(17), 1653-1656. 

Jullien, R., Kolb, M. and Botet, R. (1984). Scaling properties of growth by kinetic clustering of clusters. In Kinetics, Aggregation, Gelation, Family. F. and Landau, D.P. (eds). North Holland, Amsterdam, pp. 101-109. 

The flocculation results give strong evidence that kinetic-aUy aggregated filler clusters or networks are formed in elastomer composites, as shown schematically in Fig. 36.6. Accordingly, the model of mbber reinforcement by flexible filler clusters refers to the kinetic cluster-cluster aggregation... 

K.D. Belashchenko, V.Yu. Dobretsov, l.R. Pankratov, G.D. Samolyuk and V.G. Vaks, The kinetic cluster-field method and its application to studies of Llj-type orderings in alloys, and Kinetic features of alloy ordering with many types of ordered domain DOs-type orderings, J. Phys. Condens. Matter 11(52), 10593-10620 and 10567-10592 (1999). 

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