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Wydeven, T.

Publications and source records attributed to Wydeven, T..

At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

The preparation of calcium superoxide from calcium peroxide diperoxyhydrate

There is interest in solid materials containing a high percentage of stored oxygen for use in emergency breathing apparatus for miners and as auxiliary oxygen sources for astronauts. In theory, the amount of available oxygen in calcium superoxide, Ca(O2)2 is higher than in potassium superoxide, KO2, and its availability during use should be unhindered by the formation of a low melting and hydrous coating. The decomposition of solid calcium peroxide diperoxyhydrate, CaO2.2H2O2 has been studied, using an apparatus which allows good control of the critical reaction parameters. Samples have been prepared showing apparent superoxide contents in excess of those previously reported and higher than the theoretical 58.4% expected from a disproportionation reaction.

Ballou, E. V.↗
NASA NTRS1977

Membrane has high urea-rejection properties

Membranes are synthesized from ethylene and nitrogen in RF plasma at low power, gas-flow rates, and pressure. Ethylene and nitrogen are used because flow rate and partial pressure of each gas can be independently controlled to produce optimum conditions for synthesizing membrane. Membrane is particularly useful in recycling and purifying water.

Johnson, C. C.↗
NASA NTRS1977

Plasma polymerized coating for polycarbonate - Single layer, abrasion resistant, and antireflection

Plasma polymerized vinyltrimethoxy silane films were deposited on transparent polycarbonate substrates. The adherent, clear films protected the substrates from abrasion and also served as antireflection coatings. Posttreatment of the vinyltrimethoxy silane films in an oxygen glow discharge further improved the abrasion resistance. ESCA (electron spectroscopy for chemical analysis) and IR transmission spectra of some films were recorded, and an elemental analysis of the films was obtained.

Wydeven, T.↗
NASA NTRS1976

Abrasion-resistant coatings for plastic surfaces

Optically clear composition of organosilicon compounds insulates plastic surfaces and protects them from abrasion. Plasma polymerization process produces superior uniformity and clarity than previous coating techniques.

Wydeven, T.↗
NASA NTRS1976

The preparation of calcium superoxide for air breathing and scrubbing applications

There is interest in the preparation of high-purity calcium superoxide as an oxygen source for breathing apparatus because both the available oxygen and the capacity for carbon dioxide removal, per unit weight of superoxide, are higher than that of a number of other chemical oxygen sources. A review of earlier findings shows that the general method used by Vol'nov and coworkers for the decomposition of calcium peroxide diperoxyhydrate can yield preparations containing more than 58.4% calcium superoxide maximum predicted for an equimolar disproportionation reaction. The decomposition of solid calcium peroxide diperoxyhydrate is studied using an apparatus that allows good control of the critical reaction parameters. The removal of water from decomposing calcium peroxide diperoxyhydrate, before the same water has an opportunity to back react with the calcium superoxide formed in the reaction, constitutes the rationale of the experiments. Even with allowance for the anomalies observed in the analytical results, the yields appear to be in the 65+ percent range, and optimization of the experimental variables is still being pursued.

Ballou, E. V.↗
NASA NTRS1975

Dielectric films improve life of polymeric insulators

Degradation of polymeric insulators may be significantly reduced when polymer surfaces are coated with film having gradation of dielectric constants, larger where it is in contact with polymer and smaller at its exposed surface.

Hudis, M.↗
NASA NTRS1975

Plasma polymerization of an ethylene-nitrogen gas mixture

A procedure has been developed whereby nitrogen can be incorporated into an organic film from an ethylene-nitrogen gas mixture using an internal electrode capacitively coupled radio frequency reactor. The presence of nitrogen has been shown directly by infrared transmittance spectra and electron spectroscopic chemical analysis data, and further indirect evidence was provided by dielectric measurements and by the reverse osmosis properties of the film. Preparation of a nitrogen containing film did not require vapor from an organic nitrogen containing liquid monomer. Some control over the bonding and stoichiometry of the polymer film was provided by the added degree of freedom of the nitrogen partial pressure in the gas mixture. This new parameter strongly affected the dielectric properties of the plasma polymerized film and could affect the reverse osmosis behavior.

Hudis, M.↗
NASA NTRS1975

Moisture resistant and anti-reflection optical coatings produced by plasma polymerization of organic compounds

The need for protective coatings on critical optical surfaces, such as halide crystal windows or lenses used in spectroscopy, has long been recognized. It has been demonstrated that thin, one micron, organic coatings produced by polymerization of flourinated monomers in low temperature gas discharge (plasma) exhibit very high degrees of moisture resistence, e.g., hundreds of hours protection for cesium iodide vs. minutes before degradation sets in for untreated surfaces. The index of refraction of these coatings is intermediate between that of the halide substrate and air, a condition for anti-reflection, another desirable property of optical coatings. Thus, the organic coatings not only offer protection, but improved transmittance as well. The polymer coating is non-absorbing over the range 0.4 to 40 microns with an exception at 8.0 microns, the expected absorption for C-F bonds.

Hollahan, J. R.↗
NASA NTRS1973

Moisture-resistant coatings for optical components

Plasma polymerization technique is used to apply thin, adherent, hydrophobic coatings from chlorotrifluoroethylene monomer. Apparently much of the chlorine contained in original monomer is lost during polymerization, and characteristic C-Cl absorption in infrared region is essentially absent.

Hollahan, J. R.↗
NASA NTRS1973

Evaluation of 165 deg F reverse osmosis modules for washwater purification.

Three membrane systems have been evaluated for concentration at 165 F of wash-water contaminants. Membranes tested are polybenzimidazole (hollow fibers), cellulose acetate blend (spiral wound), and sulfonated polyphenylene oxide (plate-and-frame). Detailed membrane flux and rejection data are presented for 200-hr life tests with synthetic wash water, at two concentrations, and real wash water, at one concentration. Advantages and limitations of the membrane configurations, are discussed.

Hossain, S.↗
NASA NTRS1973

Performance of cellulose acetate butyrate membranes in hyperfiltration of sodium chloride and urea feed solution

Cellulose acetate butyrate (CAB) membranes are shown to give high salt and urea rejection with water flux of about 3 gallons/sq ft per day at 600 psig. Membranes prepared from a formulation containing glyoxal show a significant increase in flux and decrease in salt and urea rejection with drying time. Zero drying time gives maximum urea and salt rejection and is therefore most suitable for hyperfiltration of sodium chloride and urea feed solution.

Wydeven, T.↗
NASA NTRS1973

A centrifugal method for the evaluation of polymer membranes for reverse osmosis

A rapid and simple method employing the laboratory centrifuge shows promise for evaluation of membrane performance during reverse osmosis. Results are presented for cellulose acetate membranes for rejection of salt and urea dissolved solids. Implications of the study are to rapid screening of membrane performance, use in laboratories with limited facilities, and possible space waste water purification.

Hollahan, J. R.↗
NASA NTRS1972

Reverse-osmosis membranes by plasma polymerization

Thin allyl amine polymer films were developed using plasma polymerization. Resulting dry composite membranes effectively reject sodium chloride during reverse osmosis. Films are 98% sodium chloride rejective, and 46% urea rejective.

Hollahan, J. R.↗