Practical Evaluation of Commercial Rubber Carbon Blacks by X-Ray Diffraction

Abstract

Abstract Of the dozen or more reinforcing agents used in the commercial compounding of rubber, carbon blacks are outstanding in their excellence. Though no completely satisfactory theory has yet been forthcoming to explain the action of this material, the literature indicates that, among other factors, the size and shape of the ultimate carbon particles profoundly affect the characteristics of the rubber products obtained. Particle sizes of fillers and pigments are commonly determined by microscopic methods. Of those that have been suggested, the method of Gehman and Morris is perhaps most widely accepted as reliable. All microscopic methods, however, are subject to the limitation of resolving power imposed by the relatively narrow range of wave lengths in the visible and near ultraviolet which can be used for viewing and photographic purposes. Further, no distinction can be drawn between ultimate particles and compact secondary aggregates from the microscopic point of view. Thus, there always exista the possibility that microscopic particle sizes represent groups of individual particles rather than the individuals themselves.