Title:
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Efficient manufacture of emulsion intermediates in cavity-design mixers
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Emulsions are ubiquitous across the process industries and are often utilised in applications where controlled delivery of a key ingredient (e.g. an oil or water soluble compound) is an important consideration. Their functional properties e.g. the rate of absorption or coverage of a surface is generally determined by the size and size distribution of dispersed domains or microstructure. Control over the formulation, process route and type of equipment all influence the resulting microstructure. The focus of this thesis is the development of process strategies for the efficient manufacture of emulsions in novel cavity-design mixers utilising the Controlled Deformation Dynamic Mixer (CDDM). The CDDM comprises a cylindrical rotor-stator design with opposing surfaces with embedded cavities. The novel design allows flexible operation and optimisation across the spectrum of process space, defined by dispersive and/or distributive mixers. The process strategies are empirically demonstrated across several oil/surfactant types and the impact of emulsion composition, mixer geometry and process methods are studied. The resulting emulsions are assessed via light scattering measurement of the droplet domain sizes and interfacial areas. The link between microstructure and product viscosity is discussed. An important output of this work was the development of an emulsification efficiency parameter. The parameter provides a useful analytical tool for evaluating the process strategies and is used to provide insights into how the implementation of the in-line emulsification of high internal phase emulsion strategies could provide commercial opportunities via emulsifier raw materials saving and development of small footprint processes.
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