Journal of Applied Polymer Science, Vol.78, No.8, 1555-1565, 2000
A fractal approach to the mixing-microstructure-property relationship for rubber compounds
This research is concerned with exploration of the utility of fractal methods for characterizing the mixing treatment applied to a rubber compound and for characterizing the filler dispersion developed during mixing. Fractal analysis also is used for characterization of the fracture surfaces generated during tensile testing of vulcanized samples. For the purposes, the maximum entropy method, to rubber mixing, and the box counting method are applied to analyze the mixing treatment and the filler dispersion, respectively. These methods are effectively used, and it is found that fractal dimensions of mixer power traces and fracture surfaces of vulcanized rubber decrease with the evolution of mixing time while the fractal dimension of the state-of-mix also decreases. The relationship of the fractal dimensions thus determined with conventional properties such as tensile strength, electrical resistance, and fracture surfaces are then explored. Finally, the utility of fractal methods for establishing mixing-microstructure-property relationships is compared with more conventional and well-established methods such as electrical conductivity and carbon black dispersion. It is found that the characterization by the fractal concept agrees with the conclusions from these conventional methods. In addition, it becomes possible to interpret the relationships between these conventional methods with the help of the fractal concept.