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Fluoropolymer-based 3D printable pyrotechnic compositions
Dissertation (MEng)--University of Pretoria, 2017.
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| Format: | Thesis |
| Language: | English |
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University of Pretoria
2018
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| _version_ | 1867613706578296832 |
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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 | © 2018 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:2263/66199 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:40:24.731Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2018 |
| publishDateRange | 2018 |
| publishDateSort | 2018 |
| 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:2263/66199 Fluoropolymer-based 3D printable pyrotechnic compositions Focke, Walter Wilhelm u11028727@tuks.co.za Grobler, Johannes Marthinus UCTD Additive manufacturing Pyrotechnics Melt processable pyrotechnics Laser ignition 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, 2017. The work herein covers the complete process for development, production and testing of a melt processable pyrotechnic composition, with the goal of using the composition as a printing material in a fused deposition modelling (FDM) type 3D printer. 3D printing is fast becoming an area of interest for energetic materials research. This is due to the role that geometry can play in combustion performance of a composition and 3D printing’s ability to produce a variety of complex designs. Melt processable fluoropolymers were selected as oxidisers. The polymers selected for the study were FK-800® and Dyneon 31508®. Both are co-polymers of vinylidene fluoride (VDF) and chlorotrifluoroethylene (CTFE). Aluminium was the choice fuel in this instance as it had better energetic performance than the alternatives investigated. It was also deemed to be a safer fuel when considering the combustion products. Hazardous combustion products like hydrofluoric and hydrochloric acid could be suppressed by increasing the fuel loading to 30 wt.%, thereby reducing the risks associated with burning the composition. Preliminary differential thermal analysis (DTA) analysis indicated that the compositions would only ignite above 400 °C which was well above the suggested processing temperature of 230 °C as determined from thermogravimetric (TGA) analysis. These thermal analysis techniques indicated that the reactions were most likely a gas-solid reactions due to ignition temperatures being significantly lower than those associated with phase changes occurring in the fuels tested, yet above the decomposition temperatures for the oxidisers. ii Extrusion of the compositions proceeded with addition of LFC-1® liquid fluoroelastomer. This addition was made in order to order to lower the melt viscosity, thereby improving the quality of the filament produced. Compositions were extruded with an aluminium loading of 30 wt.%. Oxidiser and LFC-1® made up the rest of the mass with the LFC-1® contributions being either 7 wt.% or 14 wt.%. Burn rates, temperatures and ignition delays were all influenced by the addition of LFC-1® to the system. FK-800® was found to be a better oxidiser in this instance since its burn rates were consistent especially when compared to erratic nature of the Dyneon 31508® burns. Linear burn rates for the FK-800® increased from 15.9 mm·s−1 to 18.9 mm·s−1 with the increase in LFC-1® loading. Combustion temperature also increased by approximately 180 °C from 794 °C. Printing with the material was achieved only after significant alterations were made to the hot end used. Printing proceeded in a staged, start-stop manner. After each new layer of material was deposited the printer was cleared of material and the hot end was allowed to cool. If this procedure was not followed it led to significant preheating of the material within the feeding section of the extruder. This premature heating caused feeding problems due to softening and swelling of the material within the cold side of the hot end which led to blockages, leading to the conclusion that the composition was not compatible with the off-the-shelf hot end used in this study. Low quality printing could be achieved with both FK-800® and Dyneon 31508® compositions. This would suggest that slight compositional changes paired with the alterations made to the hot end could improve the quality of the prints to an extent that would be comparable to that of more commonplace printing materials. mi2026 Chemical Engineering MEng Unrestricted SDG-07: Affordable and clean energy SDG-09: Industry, innovation and infrastructure SDG-12: Responsible consumption and production 2018-08-17T09:42:37Z 2018-08-17T09:42:37Z 4/19/18 2017 Dissertation Grobler, JM 2017, Fluoropolymer-based 3D printable pyrotechnic compositions, MEng Dissertation, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/66199> A2018 http://hdl.handle.net/2263/66199 en © 2018 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 Additive manufacturing Pyrotechnics Melt processable pyrotechnics Laser ignition 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 Fluoropolymer-based 3D printable pyrotechnic compositions |
| title | Fluoropolymer-based 3D printable pyrotechnic compositions |
| title_full | Fluoropolymer-based 3D printable pyrotechnic compositions |
| title_fullStr | Fluoropolymer-based 3D printable pyrotechnic compositions |
| title_full_unstemmed | Fluoropolymer-based 3D printable pyrotechnic compositions |
| title_short | Fluoropolymer-based 3D printable pyrotechnic compositions |
| title_sort | fluoropolymer based 3d printable pyrotechnic compositions |
| topic | UCTD Additive manufacturing Pyrotechnics Melt processable pyrotechnics Laser ignition 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/2263/66199 |