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The viability of poly (chlorotrifluoroethylene-co-vinylidene fluoride) as an oxidiser in extrudable pyrotechnic compositions
Dissertation (MEng)--University of Pretoria, 2017.
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University of Pretoria
2017
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| _version_ | 1867613584562847744 |
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| access_status_str | Open Access |
| author2 | Focke, Walter Wilhelm |
| author_browse | Focke, Walter Wilhelm |
| author_facet | Focke, Walter Wilhelm |
| collection | Thesis |
| dc_rights_str_mv | © 2017 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, 2017. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/62771 |
| institution | University of Pretoria (South Africa) |
| last_indexed | 2026-06-10T12:38:28.311Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2017 |
| publishDateRange | 2017 |
| publishDateSort | 2017 |
| 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:2263/62771 The viability of poly (chlorotrifluoroethylene-co-vinylidene fluoride) as an oxidiser in extrudable pyrotechnic compositions Focke, Walter Wilhelm u10280449@tuks.co.za Cowgill, Andrew William Poly(chloro-trifluoroethylene) Poly(vinylidene fluoride) Pyrotechnics Additive manufacturing UCTD Engineering, built environment and information technology theses SDG-09 Engineering, built environment and information technology theses SDG-12 Dissertation (MEng)--University of Pretoria, 2017. In a push towards more environmentally friendly pyrotechnics, new greener pyrotechnic compositions need to be developed. A primary goal is to replace components such as lead, barium, and chromium in pyrotechnic compositions. Fused Deposition Modelling (FDM) is a 3D printing/additive manufacturing method whereby a thin filament is passed through a heated nozzle, and extruded onto a substrate in successive layers. This method of manufacturing could be used to produce pyrotechnic time delays based on suitable “green” polymer/fuel mixtures. Fluoropolymers are an attractive oxidising system for pyrotechnic use as fluorine is highly reactive and reacts relatively easily with common metallic fuels such as aluminium and magnesium to release a large amount of energy. Fluoropolymers are already in use as oxidisers and binders, especially in infrared decoy flares. PTFE has found wide use in the pyrotechnics industry, but is not melt-processible. A similar fluoropolymer, poly(chloro-trifluoroethylene) (PCTFE) was considered instead. PCTFE differs from PTFE in that one of the fluorine atoms in the TFE monomer has been replaced by a chlorine atom. The larger chlorine atom interferes with the packing of the polymer chains during polymerisation and, as such, may make it easier to process than PTFE. It was found that pure PCTFE degraded heavily during processing and was therefore precluded from any further study. Melt-processible copolymers containing PCTFE are available from industry. These copolymers contain vinylidene fluoride (VDF) in addition to the CTFE i.e. poly(CTFE-co-VDF). Two grades of copolymer were obtained from 3M: FK-800® resin and Dyneon® 31508 resin. These two polymers contain different ratios of CTFE to VDF. FK-800® resin was successfully extruded and showed minimal signs of degradation. Pyrotechnic films, containing aluminium powder as the fuel, were cast with both polymers using solvent techniques. Differential thermal analysis (DTA) was used to determine the ignition points of the compositions. All of the FK-800®-based compositions ignited at approximately 450 °C whilst all the Dyneon® 31508-based compositions ignited at approximately 400 °C. The energy output of the compositions was determined using bomb calorimetry. The experimental energy outputs of the FK-800®-based compositions correlated well with the predictions from the thermodynamic simulations. The maximum energy output, ~7.0 MJ∙kg1, occurred at a fuel loading between 30 – 35 wt.%. Except for one composition, the Dyneon® 31508-based compositions did not ignite in the bomb calorimeter. FK-800® was successfully extruded into a filament and showed minimal signs of degradation. In order to assess the impact of adding a solid filler on the mechanical properties and extrudability of the polymer, magnesium hydroxide was used as inactive model compound in place of aluminium. A filament of FK-800® and Mg(OH)2 was successfully compounded and produced using a filler loading of 30 wt.%. Compounding of the Dyneon 31508® with the magnesium hydroxide was unsuccessful. Addition of LFC-1® liquid fluoroelastomer improved the processibility of the Dyneon 31508® by lowering the melt viscosity. mi2026 Chemical Engineering MEng Unrestricted SDG-09: Industry, innovation and infrastructure SDG-12: Responsible consumption and production 2017-10-13T13:41:16Z 2017-10-13T13:41:16Z 2017-09-08 2017 Dissertation Cowgill, AW 2017, The viability of poly (chlorotrifluoroethylene-co-vinylidene fluoride) as an oxidiser in extrudable pyrotechnic compositions, MEng Dissertation, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/62771> S2017 http://hdl.handle.net/2263/62771 © 2017 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 | Poly(chloro-trifluoroethylene) Poly(vinylidene fluoride) Pyrotechnics Additive manufacturing UCTD Engineering, built environment and information technology theses SDG-09 Engineering, built environment and information technology theses SDG-12 The viability of poly (chlorotrifluoroethylene-co-vinylidene fluoride) as an oxidiser in extrudable pyrotechnic compositions |
| title | The viability of poly (chlorotrifluoroethylene-co-vinylidene fluoride) as an oxidiser in extrudable pyrotechnic compositions |
| title_full | The viability of poly (chlorotrifluoroethylene-co-vinylidene fluoride) as an oxidiser in extrudable pyrotechnic compositions |
| title_fullStr | The viability of poly (chlorotrifluoroethylene-co-vinylidene fluoride) as an oxidiser in extrudable pyrotechnic compositions |
| title_full_unstemmed | The viability of poly (chlorotrifluoroethylene-co-vinylidene fluoride) as an oxidiser in extrudable pyrotechnic compositions |
| title_short | The viability of poly (chlorotrifluoroethylene-co-vinylidene fluoride) as an oxidiser in extrudable pyrotechnic compositions |
| title_sort | viability of poly chlorotrifluoroethylene co vinylidene fluoride as an oxidiser in extrudable pyrotechnic compositions |
| topic | Poly(chloro-trifluoroethylene) Poly(vinylidene fluoride) Pyrotechnics Additive manufacturing UCTD Engineering, built environment and information technology theses SDG-09 Engineering, built environment and information technology theses SDG-12 |
| url | http://hdl.handle.net/2263/62771 |