Wax hardening in melt emulsification

Onaadepo, Aderomola (2024). Wax hardening in melt emulsification. University of Birmingham. Eng.D.

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Abstract

Wax-in-water emulsions can be defined as a mixture made up of one or more waxes in water. Although wax and water are immiscible materials, wax-in-water emulsions can be stabilised by using surface-active agents such as surfactants (these can be either ionic or non-ionic or a combination of both) to reduce the interfacial tension between droplets and to prevent instability scenarios such coalescence, creaming, flocculation, aggregation, etc occurring within the emulsion. Wax emulsions as they are commonly known are generally used in a wide range of applications, from personal care to coatings to surface care applications to cosmetics, etc. As versatile as they are, wax emulsions are most effective and desirable when they are stable and have a long shelf life.
This body of work employed the use of a non-ionic surfactant (Tween 20) and a Fatty Alcohol (Stearyl Alcohol or 1-Octadecanol as the wax); various compositions of these two in the presence of water were explored while evaluating how the different compositions influenced the Rheology and the particle size distribution. It was found that the compositions with lower surfactant amounts had a more polydisperse particle size distribution and consequently, reduced viscosity over time as a result of the effective packing of droplets that accompanies polydispersity. This research explores potential scenarios resulting from the use of high surfactant concentrations and the surpassing of Critical Micelle Concentration. These scenarios include micellar phase transition at ambient temperatures, the release of surfactant molecules from micelles during aging leading to the formation of new phases, and the development of lamellar phases under heat exposure.

Type of Work:

Thesis (Doctorates > Eng.D.)

Award Type:

Doctorates > Eng.D.

Supervisor(s):