SEDL / STP / STP1146-EB / STP20189S

A Photometric Study of Dilute Microcapsule Suspensions

Stern, AJ
Senior Research Chemist, the Formulation Technology Section of Monsanto Agricultural Company, a unit of Monsanto Company, St. Louis, MO

Pages: 10    Published: Jan 1993

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Abstract

Dilute suspensibility of solids, of great importance to the users of suspension concentrate formulations, is a complex subject. In order to better understand the behavior of dilute microcapsule suspensions, a photometric method has been used to quantitatively measure their sedimentation as a function of time. Applied to eight different microcapsule formulations, this method has shown that 1) microcapsule settling rates are not linear; 2) shell wall structure largely influences the degree of microcapsule flocculation and hence settling rates; and 3) in many cases, suspension and resuspension are inversely related.