Dynamic Interfacial Tension of Polymer Solutions

Morgan, Ben (2001). Dynamic Interfacial Tension of Polymer Solutions Honours Thesis, School of Engineering, The University of Queensland.

       
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Author Morgan, Ben
Thesis Title Dynamic Interfacial Tension of Polymer Solutions
School, Centre or Institute School of Engineering
Institution The University of Queensland
Publication date 2001
Thesis type Honours Thesis
Supervisor Yinghe He
Tony Howes
Total pages 103
Language eng
Subjects 0904 Chemical Engineering
Formatted abstract
Interfacial tension is recognised to play a key role in emulsion stability. Surfactants are commercially employed to reduce the interfacial tension between two phases and retard phase separation.

This inquiry examines the means by which polymer surfactants reduce interfacial tension. It has been determined that this process is dynamic and is controlled by the rate of polymer adsorption to the interface. Once adsorbed, the polymer will conform to achieve maximum possible surface coverage. This is affected by three variables: molecular weight, degree of hydrolysis, and bulk polymer concentration. These effects are the focus of this inquiry.

A full factorial experimental program was designed to determine the effect of each variable on interfacial tension. The interfacial tension has been determined from the drop volume technique. This technique is limited in the results it can obtain in the time domain due to the assumption that drops leaving the capillary have no momentum. This assumption doesnft hold at high flow rates, and consequently extrapolation of data back to t = 0, yields ƒÁ ‚ ƒÁ0. The absolute error in using this method is } 2.2 mN/m. Simulation of a model developed by Prasetya (2001) supported the relationships derived from experiments.

Coalescence time has been identified as a reliable measure of emulsion stability. A generalised view of emulsion stability is drawn from combining the findings made in the interfacial tension and coalescence time studies. It was determined that polymeric surfactants of high molecular weight and low degree of hydrolysis are most effective in stabilising an emulsion.
Keyword Polymer Solutions

Document type: Thesis
Collection: UQ Theses (non-RHD) - UQ staff and students only
 
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Created: Thu, 08 Jan 2015, 12:27:33 EST by Asma Asrar Qureshi on behalf of Scholarly Communication and Digitisation Service