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Title: An investigation into the structuring of an hydrophobic clay in silicone fluid
Author: Lewkowicz, Nina Maria
Awarding Body: University of London
Current Institution: University College London (University of London)
Date of Award: 2001
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Hydrophobic clays are one established route by which non-aqueous fluids may be structured to give viscous fluids (gels). Although known for many years for their role as rheological modifiers, the underlying mechanisms for structuring hydrophobic clay gels are poorly understood. It is the aim of the research described in this thesis to probe the microstructure of these systems and elucidate the major factors contributing to this structuring. Using a variety of analytical tools, including microscopy, thermal and rheology, the structure of the clay (dimethyl dialkyl quaternary ammonium hectorite) has been followed from its initial dry state through dispersion and final gelation. With silicone fluid as the non-aqueous liquid of interest and utilising a range of polar additives, the role of the additive has been investigated. Similarly, using these same systems, the influence of processing has been investigated over a wide range of shear regimes. The main findings of this work are a new structural description of the deagglomerated clay, a proposed mechanism for the gel formation and a detailed understanding of the relative contributions of chemical, thermal and mechanical energy on the structure formation. For the first time in this area, a comprehensive study of the effect of process conditions on the dispersion of hydrophobic clay has been completed and is reported here.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available