Thermal decomposition of PTFE in the presence of silicon, calcium silicide, ferrosilicon and iron

Książczak, A.; Boniuk, H.; Cudziło, S.

doi:10.1023/b:jtan.0000005195.46390.48

Cited by 43 publications

(14 citation statements)

References 6 publications

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“…The TGA and XRD results showed strong evidence that combustion of calcium disilicide with Viton A reacts to form calcium fluoride, consistent with the literature [8]. In order to explore the products of combustion, PAX-F-A and PAX-F-B (Table 1) were tested in a combustion calorimeter Table 2.…”

Section: Combustion Calorimetersupporting

confidence: 82%

In‐situ Remediation of Hydrogen Fluoride During a Detonation Event

Caflin¹,

Anderson²

2014

Propellants Explo Pyrotec

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Hydrogen fluoride (HF) is a known product from the combustion or detonation of explosives formulated with fluoropolymer binder systems. This presents the user with elevated risk levels during unintended combustion events or detonations in confined situations. In an effort to remediate the production of HF, calcium disilicide (CaSi2) was added to explosive formulations and the amount of HF formed was monitored. Viton A/calcium disilicide mixtures were made and the thermal decomposition characteristics studied using thermal gravimetric/differential thermal analysis (TG/DTA). The activation energy ranged from 145–190 kJ mol−1, indicative of CF scission in the Viton A binder prior to calcium fluoride formation. An energetic formulation was prepared which consisted of approximately a 5/3 mass ratio of Viton A/CaSi2. Combustion calorimetry in oxygen and air, and subsequent analysis of the residues using X‐ray diffraction (XRD) showed evidence of calcium fluoride (CaF2) formation. The decrease in HF formation was determined by trapping off gases and subsequent analysis in anion exchange chromatography of combustion and detonation products. Upon introduction of calcium disilicide into the formulation, a small decrease in HF formation was observed along with appearance of calcium fluoride and free Si in the residue. Such products are consistent with the mechanism following a general decomposition path of 2F−+CaSi2→CaF2+2Si. Under detonation conditions, the decomposition path followed nearly the same route with a net ca. 30 % decrease in HF formation, but with a portion of the silicon oxidizing slightly further to SiO2.

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Section: Combustion Calorimetersupporting

confidence: 82%

In‐situ Remediation of Hydrogen Fluoride During a Detonation Event

Caflin¹,

Anderson²

2014

Propellants Explo Pyrotec

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“…The mass losses of samples in both TG curves at 170 • C and 547 • C corresponds to the decompositions of NH 4 Cl and PTFE respectively. 15,16 In S8 with 8 wt.% PTFE addition, a sudden decrease of the heat flow with the increase of temperature was clearly seen at 842 K in the DSC curve, indicating an endothermal reaction occurred at this temperature, which was attributed to the decomposition of PTFE. 15,16 Subsequently, a small exothermic peak appeared at 921 K, indicating the exothermic reaction between Si and free radicals yielded by the decomposition of PTFE was induced.…”

Section: Resultsmentioning

confidence: 96%

“…The decomposition of PTFE is supposed to occur at the high temperature caused by the Si-N 2 exothermal reaction, which is endothermic in nature, 15,16 which is responsible for the decrease of the combustion temperature with the increase of the PTFE content from S1 to S4. The decomposition of PTFE at high temperature can be expressed by the following three step sequent reactions.…”

Section: Resultsmentioning

confidence: 99%

PTFE, an effective additive on the combustion synthesis of silicon nitride

Chen

Lin

et al. 2008

Journal of the European Ceramic Society

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“…Metal/ PTFE compositions have had considerable use as pyrotechnics [23][24][25][26][27][28][29][30], particularly as illuminants [23][24][25][26], due to the high radiant intensity of their combustion products. Recent studies on Si/PTFE combustion [3,29,31] have focused on external characteristics (i.e., oxidizer, equivalence ratio, pressure, etc. ), but have not addressed the role that SSA, active content, morphology, and particle size has on the combustion performance.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Silicon Powder Characteristics on the Combustion of Silicon/Teflon/Viton Nanoenergetics

Terry¹,

Lin

Manukyan

et al. 2014

Propellants Explo Pyrotec

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Due to its thin passivation layer, potentially good aging characteristics, and ease of surface functionalization nanoscale silicon (Si) may offer some advantages over nanoaluminum as a reactive fuel in nanoenergetic compositions, particularly with fluorine‐based oxidizers. Currently, Si nanopowder can be quite expensive and the quality of commercial powders has been found to vary drastically. As a result limited efforts have focused on the role of specific surface area, active content, morphology, and dominant particle size of the powder have on the combustion performance. In this work we report the effect of such characteristics on the combustion of silicon (Si)/polytetrafluoroethylene (Teflon)/FC‐2175 (Viton) (SiTV) nanoenergetics. A cost effective combustion synthesis route, salt assisted combustion synthesis, was used to produce several Si powders and these were directly compared to commercial nanoscale Si powders. Reactive mixtures of SiTV were burned at atmospheric conditions and burning rates, combustion temperatures, spectral intensities, and effective plume emissivities were measured. Measured combustion temperatures ranged from 1664 to 2380 K and were limited by Si powder active content. This was found to drive plume emissivity and maximum spectral intensity, which had values ranging from 0.10 to 0.55 for effective plume emissivity and 17.6 to 48.1 kW m−2 sr−1 μm−1 for maximum spectral intensity. Burning rates ranged from 0.7 to 3.4 mm s−1 and were found to be dependent on the dominant particle size of the powder. Powders synthesized with salt assisted combustion resulted in comparable burning rate, plume emissivity and maximum spectral intensity to porous Si powder (Vesta Ceramics).

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Thermal decomposition of PTFE in the presence of silicon, calcium silicide, ferrosilicon and iron

Cited by 43 publications

References 6 publications

In‐situ Remediation of Hydrogen Fluoride During a Detonation Event

In‐situ Remediation of Hydrogen Fluoride During a Detonation Event

PTFE, an effective additive on the combustion synthesis of silicon nitride

The Effect of Silicon Powder Characteristics on the Combustion of Silicon/Teflon/Viton Nanoenergetics

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