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The influence of three different intercalation methods on the properties of exfoliated graphite
Dissertation (MEng)--University of Pretoria, 2015.
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| Format: | Thesis |
| Language: | English |
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University of Pretoria
2015
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| _version_ | 1867613499801206784 |
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| access_status_str | Open Access |
| author2 | Badenhorst, Heinrich |
| author_browse | Badenhorst, Heinrich |
| author_facet | Badenhorst, Heinrich |
| collection | Thesis |
| dc_rights_str_mv | © 2015 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (MEng)--University of Pretoria, 2015. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/46247 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:37:07.698Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2015 |
| publishDateRange | 2015 |
| publishDateSort | 2015 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/46247 The influence of three different intercalation methods on the properties of exfoliated graphite Badenhorst, Heinrich Van Heerden, Xandra UCTD Graphite Hummers intercalation Gas phase intercalation Electrochemical intercalation Expanded graphite Exfoliated Graphite Engineering, built environment and information technology theses SDG-09 SDG-09: Industry, innovation and infrastructure Engineering, built environment and information technology theses SDG-12 SDG-12: Responsible consumption and production Engineering, built environment and information technology theses SDG-07 Engineering, built environment and information technology theses SDG-09 Engineering, built environment and information technology theses SDG-12 Dissertation (MEng)--University of Pretoria, 2015. It is unclear whether all intercalation techniques truly lead to the insertion of atoms between the graphite layers, or also lead to other effects which contribute to expansion. The objective of this project is to better understand the effects caused by different intercalation methods. Three intercalation methods were explored to determine the method which incurs the least damage to the surface and microstructure of the graphite intercalated compounds, yet achieves the best intercalation and therefore expansion. All the main findings are summarised below: The gas phase sample had virtually no mass loss at the point where expansion took place. Therefore the intercalation was very efficient, producing large expansion without significant mass loss. The mass loss that only occurs at the sublimation of iron chloride (320 ºC) indicates the excessive "un-intercalated" or residual iron chloride. After oxidation, before purification, the gas phase sample has 25 % residual mass; this also proves the presence of impurities and residual iron chloride in the exfoliated sample. For the Hummers and electrochemical samples, expansion and mass loss occur over a wide temperature range, this indicates that graphite oxide was formed rather than the theoretically expected "insertion of atoms between the sheets". The mass losses before 200 ˚C of the samples of the Hummers and electrochemical methods are more evidence that graphite oxide and graphite surface complexes with oxygen were produced. The Hummers and electrochemical intercalation methods show similar expansion and mass loss curves, therefore it can be concluded that the reaction mechanism for both these methods is alike. The gas phase method yields the best expansion of 250 % using the TMA, whereas both the other methods deliver approximately 220 %. Using microwave expansion the electrochemical intercalation method yields the best bulk volume expansion of 1500 %, with the gas phase sample delivering a volume expansion of 1450 %. The Hummers samples are extremely damaged. This is clear from the several and deep oxidation pits visible throughout the basal plane of these samples. The basal plane and the edges are even eroded before purification and oxidation. This intercalation technique employs oxidisers in the preparation method which additionally oxidises the samples. This explains why the Hummers method renders the most damage. The residual material on the gas phase sample acts as catalysts making the sample very reactive and consequently damaging the surface during oxidation. The partially oxidised purified gas phase sample visibly shows the pits and roughened edges. There are two “types” of intercalation. The first intercalation “type” is the actual insertion of atoms or molecules between the graphite layers, whereas the other “type” of intercalation is the production of graphite oxide. The compound comprises carbon, oxygen and hydrogen, obtained by treating graphite with strong oxidisers. The functional groups usually found in graphite oxide are carbonyl (C=O), hydroxyl (-OH), phenol amongst others and also some impurities of sulphur when sulphuric acid is used. Both these intercalation types lead to expansion. It is recommended that a more efficient method for removal of residual material in the gas phase samples be explored. It is also recommended that more research be done to determine the reaction mechanisms during the three different intercalation methods. The graphite surface complexes of the intercalated compounds and the evolved gases during expansion should be analysed. tm2015 mi2026 Chemical Engineering MEng Unrestricted SDG-07: Affordable and clean energy SDG-09: Industry, innovation and infrastructure SDG-12: Responsible consumption and production 2015-07-02T11:08:27Z 2015-07-02T11:08:27Z 2015/04/14 2015 Dissertation Van Heerden, X 2015, The influence of three different intercalation methods on the properties of exfoliated graphite, MEng Dissertation, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/46247> A2015 http://hdl.handle.net/2263/46247 en © 2015 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | UCTD Graphite Hummers intercalation Gas phase intercalation Electrochemical intercalation Expanded graphite Exfoliated Graphite Engineering, built environment and information technology theses SDG-09 SDG-09: Industry, innovation and infrastructure Engineering, built environment and information technology theses SDG-12 SDG-12: Responsible consumption and production Engineering, built environment and information technology theses SDG-07 Engineering, built environment and information technology theses SDG-09 Engineering, built environment and information technology theses SDG-12 The influence of three different intercalation methods on the properties of exfoliated graphite |
| title | The influence of three different intercalation methods on the properties of
exfoliated graphite |
| title_full | The influence of three different intercalation methods on the properties of
exfoliated graphite |
| title_fullStr | The influence of three different intercalation methods on the properties of
exfoliated graphite |
| title_full_unstemmed | The influence of three different intercalation methods on the properties of
exfoliated graphite |
| title_short | The influence of three different intercalation methods on the properties of
exfoliated graphite |
| title_sort | influence of three different intercalation methods on the properties of exfoliated graphite |
| topic | UCTD Graphite Hummers intercalation Gas phase intercalation Electrochemical intercalation Expanded graphite Exfoliated Graphite Engineering, built environment and information technology theses SDG-09 SDG-09: Industry, innovation and infrastructure Engineering, built environment and information technology theses SDG-12 SDG-12: Responsible consumption and production Engineering, built environment and information technology theses SDG-07 Engineering, built environment and information technology theses SDG-09 Engineering, built environment and information technology theses SDG-12 |
| url | http://hdl.handle.net/2263/46247 |