Modeling of strands formation in elastomeric composites

Filling of rubbers with active fillers significantly improves their strength and deformation properties. One of the possible explanations of this phenomenon is presented in this article. It is based on a well-known fact that for large deformations of the elastomer binder filled in the gaps between neighboring filler particles is in the stress-strain state close to uniaxial tension. In this case, most of the polymer chains are oriented along the axis connecting the centers of inclusions. The paper suggests that the strength of the matrix in such a state (due to orientation) should be higher in comparison with other possible states with the same strain intensity. An dequate strength criterion was developed to account for this effect. The results of simulating the elastomeric binder destruction around two absolutely solid spherical inclusions are presented. A model of an incompressible hyperelastic material whose properties are given by a neo-Hookean potential was used to describe the properties of an elastomeric matrix. In the framework of computer experiments it was shown that when the system is deformed, the binder breaks should appear not in the gap between the filler particles, but at some distance from it. The elastic bond between the inclusions remains. A polymeric fiber (nanostrand) is formed between the inclusions, capable of withstanding higher tensile loads. It is known that layers with other physical-mechanical properties can be formed near the filler particles. Solutions are obtained for the problems in which the matrix in the gaps between the filler particles has a higher modulus to evaluate the possible influence of such layers. It is that this factor has virtually no effect on the emergence and formation of strands.