Polyampholytes are polymers that have both positively and negatively charged groups in the same chain. In recent years polyampholytes have started to be used in papermaking applications, as well as in sludge treatment processes. Benefits, in the case of papermaking, have included increased dry-strength and faster removal of water. But the molecular mechanisms by which such benefits are achieved have not been fully understood. This thesis project focused on effects related to polyampholyte charge density. A series of polyampholytes with a fixed charge ratio but different charge density was used for the experiments. Analysis methods included pH titrations, streaming current titrations, and adsorption isotherms. From pH titrations the charge density of cationic and anionic groups under different pH were calculated. From streaming current tests the net apparent charge density under different pH was calculated. And from adsorption tests it was found that the highest adsorbed amounts were achieved in certain cases corresponding to the highest content of ionic groups on the polyampholytes. Adsorption depended strongly on pH. Substantial differences were observed when comparing results obtained with polyampholyte samples versus ordinary polyelectrolyte samples with same charge density of cationic or anionic groups.
| Identifer | oai:union.ndltd.org:NCSU/oai:NCSU:etd-06182006-220545 |
| Date | 28 June 2006 |
| Creators | Wang, Yun |
| Contributors | Martin Hubbe, Orlando Rojas, Dimitris Argyropoulos |
| Publisher | NCSU |
| Source Sets | North Carolina State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://www.lib.ncsu.edu/theses/available/etd-06182006-220545/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to NC State University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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