<p>The ignition of energetic materials, and specifically solid propellants, is a complex process</p>
<p>that must be safe, consistent, and precisely controlled. There is a wide range of applications with</p>
<p>specific ignition requirements for solid propellants including inflation of airbags, propulsion</p>
<p>systems (including rockets), as well as arm and fire devices. Currently, electrical or percussion</p>
<p>pyrotechnic igniters are most the commonly used ignition systems. These systems must be</p>
<p>carefully designed to deliver the proper amount of energy to a specified surface area of the</p>
<p>propellant. A photon light source (i.e. flash or laser-based, ranging from UV to IR wavelengths)</p>
<p>can potentially be used to ignite energetic materials with lower input energy and more precise</p>
<p>spatial and temporal control, thereby improving safety and reliability by eliminating electrical</p>
<p>systems used in pyrotechnic igniters. In addition, they could be potentially safer from stray</p>
<p>electrical charges causing unintentional ignition.</p>
<p>The purpose of this work is to further explore the potential of optical ignition for energetic</p>
<p>systems and identify ideal materials that can be used for optical ignition. In order to identify</p>
<p>optically sensitive materials, we will study ignition energies, ignition delays, flame temperatures,</p>
<p>and other combustion characteristics for possible energetic materials. This research addresses a</p>
<p>gap in understanding of optical ignition for energetic materials, as finding and integrating materials</p>
<p>that are optically sensitive while still being practical can be extremely challenging. These</p>
<p>challenges include: (1) a lack of absorptivity to optical wavelengths in the UV to low-IR range,</p>
<p>and subsequently, a very high sensitivity to input energy at the absorptive wavelengths that makes</p>
<p>sustained ignition difficult, (2) a need for full density materials in practical energetic systems,</p>
<p>while optically sensitive materials are exceedingly difficult to ignite as packing density increases</p>
<p>due to heat transfer, and (3) the lack of research regarding novel fuels/oxidizers for the specific</p>
<p>purpose of optical ignition.</p>
<p>Metal/fluoropolymer energetic materials have been of interest to the energetic materials</p>
<p>community for many years. Due to fluorine’s excellent oxidizing ability, they can be used in</p>
<p>composite materials with metal fuels to produce energetic materials for a wide variety of</p>
<p>applications. Polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polycarbon</p>
<p>13</p>
<p>monofluoride (PMF), and terpolymers such as tetrafluoroethylene, hexafluoropropylene, and</p>
<p>vinylidene fluoride (THV) have already seen extensive use in applications ranging including</p>
<p>protective coatings, strain gauges, and electronics. However, when combined with metals such as</p>
<p>lithium, magnesium, aluminum, or titanium, they also present an opportunity for a wide variety of</p>
<p>energetic materials. For this study, metal/fluoropolymer composites present a novel opportunity</p>
<p>for exploring optical ignition of widely absorptive, full-density energetic materials. This work will</p>
<p>characterize the combustion and sensitivity of metal/fluoropolymer composites to provide novel</p>
<p>materials for optical ignition of energetics.</p>
<p>Specifically, this work will begin with finding a suitable energetic composite that is optically</p>
<p>sensitive. Once this material has been identified, research will be done to thoroughly characterize</p>
<p>the optically sensitive composite by looking at additive manufacturability, flame temperatures, and</p>
<p>ignition sensitivities from various methods and formulations. Once the material has been</p>
<p>thoroughly characterized, it will be implemented into solid propellants to test the feasibility of the</p>
<p>material in practical energetic systems. Finally, the lessons learned from this work will be applied</p>
<p>to novel formulations to identify new optically sensitive energetic composites.</p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/21598539 |
| Date | 28 November 2022 |
| Creators | Kyle Uhlenhake (14153403) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/thesis/OPTICAL_IGNITION_AND_COMBUSTION_CHARACTERIZATION_OF_METAL_FLUOROPOLYMER_COMPOSITES/21598539 |
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