Morphology of aggregates

Abstract This paper gives a new geometrical method for analyzing the shape of colloidal aggregates from electron micrographs. The silhouette of an aggregate is treated as a plane figure, for which are calculated the radii of gyration about the two central principal axes in the plane. The ratio of these radii is taken as the anisometry of the figure, and other parameters are also calculated including the area and bulkiness, as well as a “structure factor” which expresses the excess area swept out by the figure as it rotates. These parameters characterize the two-dimensional projection of the aggregate; in order to relate this to the three-dimensional aggregate, we have generated floes by computer simulation (based on the method of M. Vold) and determined their two-dimensional parameters. Qualitative similarity is shown between the appearance of the simulated floes and of actual electron micrographs of carbon black.

[1]  H. P. Hutchison,et al.  An Open-structured Random Solid , 1965, Nature.

[2]  J. Watson.  The Morphology of Carbon Black Particles in Shadow‐Cast Specimens , 1949 .

[3]  T. Church.  Problems associated with the use of the ratio of Martin's diameter to Feret's diameter as a profile shape factor☆ , 1968 .

[4]  G. Kraus,et al.  Interactions of Elastomers and Reinforcing Fillers , 1965 .

[5]  F. A. Heckman,et al.  Progressive Oxidation of Selected Particles of Carbon Black: Further Evidence for a New Microstructural Model , 1966 .

[6]  G. Herdan,et al.  Small particle statistics , 1954 .

[7]  D. Sutherland,et al.  Comments on Vold's simulation of floc formation , 1966 .

[8]  S. Newman,et al.  Barus effect in filled polymer melts , 1965 .

[9]  F. A. Heckman.  Microstructure of Carbon Black , 1964 .

[10]  G. D. Scott,et al.  Packing of Spheres: Packing of Equal Spheres , 1960, Nature.

[11]  C. C. Furnas.  Grading Aggregates - I. - Mathematical Relations for Beds of Broken Solids of Maximum Density , 1931 .

[12]  T. C. Patton,et al.  Paint flow and pigment dispersion , 1964 .

[13]  M. J. Vold.  Computer simulation of floc formation in a colloidal suspension , 1963 .

[14]  J. Brennan,et al.  Carbon black–polymer interaction: A measure of reinforcement , 1964 .

[15]  D. Sutherland,et al.  A theoretical model of floc structure , 1967 .

[16]  Carl Barus,et al.  Isothermals, isopiestics and isometrics relative to viscosity , 1893, American Journal of Science.