Michalik, Stephen J.
(2003)
DESIGN, SYNTHESIS, AND OPTIMIZATION OF NON-FLUOROUS, CO2-PHILIC POLYMERS: A SYSTEMATIC APPROACH.
Master's Thesis, University of Pittsburgh.
(Unpublished)
Abstract
Research done during the last 15 years has proven that one can use CO2 as a solvent in many processes. There have been compounds from surfactants to chelating agents that were shown to be soluble in CO2 to low pressures. By attaching CO2-philic groups to polymer chains, previously insoluble polymers have exhibited miscibility with CO2, allowing for applications such as emulsion polymerization, dispersion polymerization, dissolution of proteins, extraction of heavy metals, and other processes. Unfortunately, the most successful CO2-philes, the fluorinated polymers, have a very unfavorable economic drawback that makes their commercial use impractical. As a result, this work seeks to determine the characteristics that could be built into a carbon based polymer to allow for the polymer to be miscible with CO2 down to low pressures.Several design elements were considered in this work: the cohesive energy density, the free volume, and the Lewis acid/base interactions with CO2 acting as a Lewis acid. Lowering the cohesive energy density and increasing the free volume limited undesirable polymer-polymer interactions, while the addition of Lewis base groups to the polymer in the backbone and as grafted side chains increased the favorable polymer-CO2 interactions. Several side chains containing Lewis base groups were first grafted onto silicon-backbone polymers. The effects of the grafting and degree of substitution were determined, and the best performing side chains were then grafted onto a polyether backbone to investigate their interactions with the carbon/oxygen backbone.This work made clear the importance of adding optimal amounts of a Lewis base group to the polymer, whether in the backbone or as a grafted side chain. While attaining a low cohesive energy density and maintaining a low glass transition temperature are important, polymers with these features alone performed very poorly in CO2. The addition of Lewis base groups in the backbone or as a side chain dramatically improved the solubility of the polymers and showed the importance of favorable polymer-CO2 interactions. A key observation was that an ether functional group may provide the same Lewis acid/base interaction with CO2 that is seen with the acetate group.
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Details
| Item Type: |
University of Pittsburgh ETD
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| Status: |
Unpublished |
| Creators/Authors: |
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| ETD Committee: |
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| Date: |
3 September 2003 |
| Date Type: |
Completion |
| Defense Date: |
24 April 2003 |
| Approval Date: |
3 September 2003 |
| Submission Date: |
8 May 2003 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Chemical Engineering |
| Degree: |
MSChE - Master of Science in Chemical Engineering |
| Thesis Type: |
Master's Thesis |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
carbon dioxide; cloud point pressure; CO2; poly(epichlorohydrin); poly(propylene oxide); poly(propylene); poly(vinyl acetate); polymer; Lewis base; solubility |
| Other ID: |
http://etd.library.pitt.edu:80/ETD/available/etd-05082003-125751/, etd-05082003-125751 |
| Date Deposited: |
10 Nov 2011 19:44 |
| Last Modified: |
15 Nov 2016 13:43 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/7826 |
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