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Polymers 2018, 10(12), 1352;

Reversible Stability of Emulsion and Polymer Latex Controlled by Oligochitosan and CO2

Unconventional Petroleum Research Institute, China University of Petroleum, Beijing 102249, China
Sinopec Northwest China Oilfield Company, Urumqi 830011, China
Polymer Research Institute, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, China
Authors to whom correspondence should be addressed.
Received: 29 October 2018 / Revised: 26 November 2018 / Accepted: 1 December 2018 / Published: 6 December 2018
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The addition of salt to a colloid solution ensures that emulsions can be easily separated into two phases and that polymer latexes can be coagulated. The switchable stability of emulsions and polymer latexes would improve the properties for their current applications. A switchable process of salt addition can be achieved using CO2 and switchable water, and it is a novel, benign approach to achieving a switchable ionic strength in an aqueous solution. However, the problem associated with switchable water is that its additives are all synthetic tertiary amines, most of which are harmful to human beings and the environment. Oligochitosan, as a natural product, can also be used as a switchable water additive. In this paper, a new switchable water system using oligochitosan to change the ionic strength was explored for use in several potential industrial applications. The conductivity of the aqueous solution of oligochitosan (0.2 wt.%) was switched from 0.2 to 331 μS/cm through the addition and removal of CO2. Oligochitosan and CO2 were successfully utilized to reversibly break a crude oil emulsion. Polystyrene (PS) latexes could also be reversibly destabilized; the zeta potential of the PS latex changed between −5.8 and −45.2 mV in the absence and presence of CO2 after oligochitosan was dissolved in the PS latex. The use of oligochitosan is a more environmentally friendly means for reversibly separating colloid solutions. View Full-Text
Keywords: CO2; oligochitosan; salt addition; latex; emulsion CO2; oligochitosan; salt addition; latex; emulsion

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Li, L.; Guo, N.; Zhang, X.; Ou, W.; Yang, S.; Su, X.; Feng, Y. Reversible Stability of Emulsion and Polymer Latex Controlled by Oligochitosan and CO2. Polymers 2018, 10, 1352.

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