Effect of Aggregation of the Particles of Filler in a Dispersion-Filled Composite on the Fractal Dimensionality of the Surface

Due to the extensive development of the methods of fractal analysis for the last 15 years, it becomes possible to clarify an important role played by the surface of dispersed particles in various physical and chemical processes. It was discovered that the surfaces of various dispersed particles, including dispersed particles used as fillers of polymers, possess the property of self-similarity within a fairly large interval of linear scales and that the dimensionality of the surfaces of particles of the filler d is not integer and belongs to the interval 2 # < dn < 3. This means that the indicated surfaces are fractals. Moreover, the higher the degree of fractality (roughness) of the surface of the filler, the greater its contribution to the thermodynamic properties of the system. In the fractal dimensionality dn of the surfaces of particles (aggregates of particles) of the filler was experimentally found for the dispersion-filled polyhydroxyester-graphite (PHE-Gr) composites. It was also discovered that the fractal dimensionality dn increases with the volume content of the filler *qn and, in addition, the influence of dn on the plasticity of the composites becomes more pronounced. In it was also assumed that the indicated increase is caused by the aggregation of particles of the filler. The aim of the present work is to give theoretical confirmation of the assumption made above and show that the sole cause of increase in dn with the concentration *qn is the aggregation of particles of graphite in PHE-Gr composites.