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Effective dispersants for concentrated, nonaqueous suspensions

Published online by Cambridge University Press:  31 January 2011

I. Sushumna ,
R.K. Gupta  and
E. Ruckenstein
I. Sushumna
Affiliation:
Department of Chemical Engineering, State University of New York at Buffalo, Buffalo, New York 14260
R.K. Gupta
Affiliation:
Department of Chemical Engineering, State University of New York at Buffalo, Buffalo, New York 14260
E. Ruckenstein
Affiliation:
Department of Chemical Engineering, State University of New York at Buffalo, Buffalo, New York 14260
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Abstract

With the aim of identifying effective dispersants that would yield stable, high solids loading (≥60 vol.%) suspensions of oxides, carbides, or nitrides in nonaqueous carriers such as paraffinic oils, a number of dispersants were evaluated, using in most cases A16SG grade alumina from Alcoa as the filler. Among those evaluated were some common dispersants, such as menhaden fish oil and oleic acid, and commercial dispersants not commonly used in ceramic processing, such as polymeric fatty esters and petroleum sulfonates. More importantly, a few dispersants were synthesized and evaluated. The latter dispersants contained straight or cyclic (benzenic) side chains located far from the head group on 18 carbon main-chain fatty acid molecules. Among these, the dispersants with a 5–10 carbon side chain or with a benzenic side chain yielded very fluid suspensions (≥60 vol.%) compared to those with long polymeric or oligomeric side chains, or with no side chains, or the commercial dispersants; in some cases, for the same solid loading, the suspension viscosities were an order of magnitude lower with the synthesized side chain dispersants. These results indicate that molecules with an optimum side chain length located sufficiently far from the head group and an optimum backbone (main chain) constitute the most effective dispersants for concentrated suspensions. By combining the advantages provided by wider particle size distributions and by these effective dispersants, suspensions highly concentrated (up to 74 vol.%), and yet processable and “flowing” paste-like have been prepared.

Type
Articles
Information
Journal of Materials Research , Volume 7 , Issue 10 , October 1992 , pp. 2884 - 2893
Copyright
Copyright © Materials Research Society 1992

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References

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