Senior Research Chemist Stepan Company Northfield, IL, United States
Abstract: Unlike common nonionic alcohol ethoxylates having EO (ethylene oxide) group as hydrophilic head, PO (propylene oxide)-incorporated alcohol alkoxylates and EOPO block copolymers display unique low foam and defoaming properties that make these surfactants highly suitable for applications such as Clean-in-Place and Rinse-Aids. However, despite the unique foam properties as well as practicality in multiple industrial applications, the study of their foam properties has been limited due to a lack of systematic approaches and methodologies to evaluate such a fragile foam. In this work, practical approaches and methods for characterizing foamability and foam stability using Dynamic Foam Analyzer will be described, together with detailed studies on the low foaming and defoaming behaviors of several alcohol alkoxylates and EOPO block copolymers having different structure. The stabilizing/destabilizing effects of surfactant concentration and alkoxylate structure in multiple conditions will be presented. The significance of the molecular structural manipulation to low foaming and defoaming response will be illustrated and the commercial value of PO-incorporated nonionic alkoxylates versus alcohol ethoxylates will be highlighted.
