Effect of silica particles on foam stability

Chu, Shih-Chi (2012). Effect of silica particles on foam stability. University of Birmingham. Ph.D.


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This thesis investigates how the properties of foams can be modulated by the addition of particles to the foam solution. As a model system hydrophobic and hydrophilic silica particles were used.

The de-agglomeration of hydrophilic silica particles in water and surfactant solutions was studied.
Two methods are investigated: ultrasound cavitation (UC) and mechanical agitation (MA). The efficiency of these two methods was compared with respect to their ability to produce foams and to de-agglomerate both hydrophilic and hydrophobic silica particles.

The same particles were used as additions to protein and surfactant foaming solutions. In the experiments, the amount and types of particles, proteins and surfactants were varied in the foaming dispersions. Then UC and MA were used to foam the dispersions and the drainage, breakage and microstructure of the resulting foams were examined. In the protein foaming solutions, both casein and whey protein foams were considered. In the surfactant foaming solution, C12LAS and CTAB were used.

Partially hydrophobic silica particles were used in pure water to generate foam. Foamability and foam stability both increased with increasing concentration of particles. Moderately hydrophobic particles gave optimum foamability whilst no foam could be produced with fully hydrophilic particles. In the foam rheology test, a transition from solid-like to liquid-like behaviour was found while the foam with addition of SCMC exhibited no such transition.

Type of Work: Thesis (Doctorates > Ph.D.)
Award Type: Doctorates > Ph.D.
College/Faculty: Colleges (2008 onwards) > College of Engineering & Physical Sciences
School or Department: School of Chemical Engineering
Funders: None/not applicable
Subjects: T Technology > TP Chemical technology
URI: http://etheses.bham.ac.uk/id/eprint/3778


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