Abstract
The dispersion process of agglomerated soldis, such as carbon-black, into rubbers and plastics is still not understood to a satisfactory extent. Dispersive mixing is commonly carried out in roll mills, internal mixers and continuous intensive mixers. It is accomplished by repeated passage of the mixture, through converging-tight clearance high stress regions, of the mixers. The key design and operational variables are the geometry of this region, the stress history of the fluid element, and the passage distribution function. A laboratory apparatus was designed and built to enable a systematic study of the effect of these variables on mixing. The apparatus, and experimental results are described. Results verify that the number of passages is a dominant variable in dispersive mixing, and proves the utility of the apparatus to study the dispersive mixing process.
Acknowledgement
This research was supported by a grant from the National Council for Research and Development, and the KFA Juelich, West Germany. The work was done in collaboration with Professor G. Menges, Dr. Limper and Mr. Grajewski from the Institut fur Kunststoffverarbeitung at Aachen. The authors wish to thank Professor Z. Rigbi from the Chemical Engineering Department at the Technion, and Dr. P. Fadhukan from Firestone Corp. Akron, Ohio, for their helpful advice in rubber compounding and cryomicrotoming, respectively and Ms. Suzane Izsak for doing much of the microtomy and photography. Thanks are also due to Mr. B. Sapir for developing and printing the photographs. Special thanks are due to Mr. B. Smolianski who built the tester, and to the Israeli Rubber Research Association who provided the microtome for the study.
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© 1987 Walter de Gruyter GmbH, Berlin/Boston, Germany
