Public reporting burden tor this collection of information is estimated to average 1 hour per response, including the time for reviewing Instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Inflatable structures are being developed for use in space to take advantage of the potential for lower packaging volumes and lighter weights. These structures may consist of thin polymer membranes as well as more robust inflatable, then rigidizable, structural elements. For space applications, it must be shown that the materials can tolerate the orbital environment. This includes the effects of solar radiation and electron/proton radiation on the optical properties and mechanical response of the materials, as well as atomic oxygen effects for possible LEO applications. The highest radiation concern is with the thin-film materials, e.g., the canopy and reflector of an antenna or components of a sun shade or solar sail. All materials used in an inflatable structure need to be capable of tolerating the orbital environment and maintaining properties within the mission requirements.The approach to assessing the effects of space environment on materials begins with consideration of the orbital environment. The solar radiation spectrum is not orbital dependent, but the radiation from electrons and protons varies by orders of magnitude, depending on the particular orbit. The atomic oxygen environment is strongly dependent on altitude and solar activity. Once an orbit has been defined, the atmospheric models are available to calculate the flux and energy of the particle radiation. The orbital lifetime then is used to calculate dose levels and solar exposures that the materials must tolerate. With the environment specified, the expected dose in the materials can then be calculated. If damage thresholds are available for the particular materials involved, possible degradation can be predicted; if not, a ground or orbital test is needed. For a ground test to assess the durability of a material in orbit, the methodology is to predict the dose levels in the materials, which then drive the test parameters.The orbital environment of solar, electron and proton radiation are discussed. Typical levels for a LEO, MEO, and GEO orbit are presented, and examples of test conditions to simulate the space environment in a ground test on materials properties are discussed. Available results on materials for inflatables are presented.
Trifluoromethylfluoroformate (CF30CFO) was produced as a secondary product in the mercuryphotosensitized oxidation of 2-C,Fs. It was identified by its mass, infrared, and fluorine n.m.r. spectra, as well as by vapor density and physical property determinations.Canadian Journal of Chemistry, 46. 332 (1968) The only published report of C F 3 0 C F 0 was by Aymonino (I), who produced it from the photolysis of a inixture of C F 3 0 F and CO, listed some of its physical properties, and reported its infrared spectrum. We wish to report the formatioil of C F 3 0 C F 0 as a secondary product in the mercury-sensitized oxidation of 2-C4Fs. In addition to the properties reported 'Present address: Department of Chemistry, Penn State University, University Park, Pennsylvania 16802.by Aymonino, we have also obtained the mass and fluorine nuclear magnetic resonance (n.m.r.) spectra.In the mercury-photosensitized oxidation of 2-C4Fs, it was observed (2) that the rate of formation of CF3CF0 decreased as the exposure time was lengthened. Simultaneously, a secondary product was formed. Thus, it appeared that C F 3 C F 0 decomposed (presumably by mercury sensitization) to ultimately yield the secondary product. To check this hypothesis, Can. J. Chem. Downloaded from www.nrcresearchpress.com by 34.216.127.252 on 05/10/18For personal use only. NOTES 333we examined the mercury-sensitized oxidation of C3F6 for lengthy exposures, where CF3CF0 is also produced, and observed the same results.The secondary product was isolated by gas chromatography, utilizing a 20 ft column composed of 20% fluorolube FS-5 on firebrick at 0 "C. The retention time of the secondary product was identical with that for perfluoropropyleneoxide, another product in the C3F6 system. Since with 2-C4Fs, pe~uoropropylene-oxide is not produced, a clean separation could be effected in this system. Gas density measurements of the secondary product gave a molecular weight of 131 compared with the expected value of 132 for CF30CF0. The mass spectrum of the product is summarized in Fig. 1. In order to co~npensate for any material bleeding from the column, a sample was collected at the appropriate retention time from an unexposed mixture of 2-C4Fs and 02. This background mass spectrum indicated small anlounts of fluorocarbons containing no oxygen. The sample from the photolyzed mixture gave intense peaks at m/e 28(CO+), 44(C02+), 47(FCO+), 66(CF20+), 69(CF3+), and 85(CF30+). The peak of highest m/e is at 132 and must correspond to the parent molecule ion. The low intensity of the parent ion is a common feature of fluorocarbon mass spectra. Significantly, there are no peaks suggesting a carbon-carbon bond. The mass spectrum clearly indicates that the molecule is C F 3 0 C F 0 .The infrared spectrum, shown in Fig. 2, supports the identification as C F 3 0 C F 0 . The spectrum is simple with bands at 5. 28, 7.70, 7.93, 8.50, 9.80, 11.20, 13.05, and 15.0 p. The prominent band at 5.28 p, characteristic of the -CFO group, is slightly shifted from the value of 5.25 p reported b...
The mercury photosensitized oxidation of 1,3-C,F, gives nearly equal amounts of C F 2 0 and a new compound 2,3-epoxyperfluoropropionylfiuoride and smaller amounts of c-C3F4. The infrared (i.r.) and mass spectra of 2,3-epoxyperfiuoropropionylfluoride are presented.Canadian Journal of Chemistry, 47, 2329 (1969) We wish to report the synthesis and identifica-under all operating conditions, though their tion of 2,3-epoxyperfluoropropionylfluoride (I) absolute quantum yields varied markedly. Perfluorocyclopropene, which has been described /O\ ,Yo previously (2), is produced in smaller quantities.
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