Scratch resistant plastic lenses
Three-step plasma deposition process coats plastic lenses with strongly adhering scratch-resistant polymer film.
Kubacki, R. M.↗
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Results for “Polymer films”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Friction and wear of polyethylene oxide polymer having a range of molecular weights
Sliding friction and wear experiments were conducted at light loads (25 to 250 g) with various molecular weights of the polyethylene oxide polymer sliding on itself and iron. Results of the experimental investigation indicate that: (1) the coefficient of friction for the polymer decreases with increasing molecular weight; (2) friction coefficient is higher for the polymer sliding on itself than it is for the polymer sliding on iron; (3) at sufficiently high loads localized surface melting occurs and the friction coefficient is the same for the polymer sliding on itself and iron; (4) fracture cracks develop in the sliding wear track at higher but not lower sliding velocities, reflecting a strain rate sensitivity to crack initiation, and (5) the friction coefficient for the polymer sliding on iron increases with the formation of a polymer film on the iron surface.
Buckley, D. H.↗
Solar Concentrator is Gas-Filled
Proposed reflector for concentrating solar rays is made of two flexible polymer films with pressurized gas between them. First film is clear, serving as a protective cover and pressure envelope; second film is metalized to serve as concentrating mirror. Focal length of mirror is adjusted by changing gas pressure.
Hale, R. R.↗
Strength of anisotropic wood and synthetic materials
The possibility of using general formulas for determining the strength of different anisotropic materials is considered, and theoretical formulas are applied and confirmed by results of tests on various nonmetallic materials. Data are cited on the strength of wood, plywood, laminated wood plastics, fiber glass-reinforced plastics and directed polymer films.
Ashkenazi, Y. K.↗
Radiation response and electrical properties of polymer energy storage capacitors: PVF2, Polysulfone, and Mylar
Efforts were made to develop a polymer film capacitor that is tolerant to radiation. The capacitors are to be utilized in a high voltage pulse discharge application. Radiation response data at high dose/dose rate levels are presented for polyvinylidene fluoride (PVF2), polysulfone, and Mylar. The results show that PVF2 is the most radiation tolerant while Mylar is the least tolerant. The data also show that the radiation response is quite dependent on operating electric stress.
Edwards, L. R.↗
Functional membranes. Present and future
The present situation and the future development of the functional membrane are discussed. It is expected that functional membranes will play increasingly greater roles in the chemical industry of the coming decade. These membranes are formed from polymer films, liquid membranes or bilayer membranes. The two most important technologies based on the polymeric membrane are reverse osmosis and ion exchange. The liquid membrane is used for separation of ionic species; an extension of the solvent extraction process. By using appropriate ligands and ionophores, highly selective separations are realized. The active transport is made possible if the physical and chemical potentials are applied to the transport process. More advanced functional membranes may be designed on the basis of the synthetic bilayer membrane.
Kunitake, T.↗
Space environmental effects on materials
Research efforts at NASA-Langley to characterize the durability of composite materials which are candidates for use as components on various space hardware systems are reviewed. The material applications include large space structures, antennas, cables, thermal control coatings, solar reflectors, and satellite power systems. Simulation facilities have been built to study radiation effects on polymer matrix composites, and the dimensional stability of the matrix composites and tension stabilized cables. Numerical models are being developed for radiation effects on the mechanical, physical, and optical properties. Additionally, chemical and microstructural analyses are performed to identify damage mechanisms and the limits of effectiveness of accelerating life tests. It is noted that no residual strength reduction has been detected in polymer films after dosages of 5 billion rads of electron radiation.
Tenney, D. R.↗
Characterization and measurement of polymer wear
Analytical tools which characterize the polymer wear process are discussed. The devices discussed include: visual observation of polymer wear with SEM, the quantification with surface profilometry and ellipsometry, to study the chemistry with AES, XPS and SIMS, to establish interfacial polymer orientation and accordingly bonding with QUARTIR, polymer state with Raman spectroscopy and stresses that develop in polymer films using a X-ray double crystal camera technique.
Buckley, D. H.↗
Laser-assisted solar cell metallization processing
Laser assisted processing techniques utilized to produce the fine line, thin metal grid structures that are required to fabricate high efficiency solar cells are investigated. The tasks comprising these investigations are summarized. Metal deposition experiments are carried out utilizing laser assisted pyrolysis of a variety of metal bearing polymer films and metalloorganic inks spun onto silicon substrates. Laser decomposition of spun on silver neodecanoate ink yields very promising results. Solar cell comb metallization patterns are written using this technique.
Dutta, S.↗
Towards an organic photobattery - Photovoltaic properties of some thermal copolyamino acids
Thermal copolymers of amino acids have been examined as a novel material for photovoltaic devices. Due to the steric effects of amino acids during polymerization, these polymers are highly ordered, and pigments such as flavins and pterins are formed as part of the polymer. The controllably varied composition of the amino acids in the polymer makes it possible to get either electron-donor or electron-acceptor, or both kinds of groups in varying degrees. The constituent photosensitive element has been made either of photosensitive polymer film or spherule.
Przybylski, A. T.↗
NASA space materials research
The effect of the space environment on: (1) thermal control coatings and thin polymer films; (2) radiation stability of 250 F and 350 F cured graphite/epoxy composites; and (3) the thermal mechanical stability of graphite/epoxy, graphite/glass composites are considered. Degradation in mechanical properties due to combined radiation and thermal cycling is highlighted. Damage mechanisms are presented and chemistry modifications to improve stability are suggested. The dimensional instabilities in graphite/epoxy composites associated with microcracking during thermal cycling is examined as well as the thermal strain hysteresis found in metal-matrix composites.
Tenney, D. R.↗
Characterization and measurement of polymer wear
Analytical tools which characterize the polymer wear process are discussed. The devices discussed include: visual observation of polymer wear with SEM, the quantification with surface profilometry and ellipsometry, to study the chemistry with AES, XPS and SIMS, to establish interfacial polymer orientation and accordingly bonding with QUARTIR, polymer state with Raman spectroscopy and stresses that develop in polymer films using a X-ray double crystal camera technique.
Buckley, D. H.↗
Potential energy surfaces for atomic oxygen reactions: Formation of singlet and triplet biradicals as primary reaction products with unsaturated organic molecules
The experimental study of the interaction of atomic oxygen with organic polymer films under LEO conditions has been hampered by the inability to conduct detailed experiments in situ. As a result, studies of the mechanism of oxygen atom reactions have relied on laboratory O-atom sources that do not fully reproduce the orbital environment. For example, it is well established that only ground electronic state O atoms are present at LEO, yet most ground-based sources are known to produce singlet O atoms and molecules and ions in addition to O(3P). Engineers should not rely on such facilities unless it can be demonstrated either that these different O species are inert or that they react in the same fashion as ground state atoms. Ab initio quantum chemical calculations have been aimed at elucidating the biradical intermediates formed during the electrophilic addition of ground and excited-state O atoms to carbon-carbon double bonds in small olefins and aromatic molecules. These biradicals are critical intermediates in any possible insertion, addition and elimination reaction mechanisms. Through these calculations, we will be able to comment on the relative importance of these pathways for O(3P) and O(1D) reactions. The reactions of O atoms with ethylene and benzene are used to illustrate the important features of the mechanisms of atomic oxygen reaction with unsaturated organic compounds and polymeric materials.
Jaffe, Richard L.↗
Space environmental effects on polymeric materials
A study is presented of the effect of radiation on polymers. It helps to estimate the impact of the space environment on composite structures. Two commercially available polymer films were used; a polyetherimide, and a polysulfone. Both films were irradiated in vacuum with 85 KeV electron. Properties of the films before and after irradiation were monitored by tensile elongation measurements, ultraviolet/visible spectroscopy, glass transition temperature measurements, gel permeation chromatography, and infrared spectroscopy. The results of these characterizations are presented and briefly discussed.
Kiefer, Richard L.↗
Method and apparatus for maintaining thermal control in plasma conditions
An apparatus and method are disclosed for determining the effects of exposure of oxygen plasma on a thin film polymer whose bulk is maintained at a predetermined temperature. The apparatus includes a chamber having a specimen therein. A plasma environment is provided in the chamber. A closure member is provided for sealing the chamber after the specimen is introduced into the chamber. The closure member also serves as a support for the test apparatus which includes a cooling coil. A platform having the test specimen thereon is supported on the cooling coil to be cooled by coolant flowing through the cooling coils. A thermoelectric module is supported on the platform to assist in maintaining a low test temperature for the test samples. The temperature of the sample is monitored by a thermocouple probe which is in contact with the sample. Any change in bulk sample temperature caused by the thermocouple probe is quickly adjusted to maintain the initial bulk temperature by the thermoelectric module.
Whitaker, Ann F.↗
Colorimetric Detection Of Substances In Liquids And Gases
Thin polymer films containing solvatochromic dyes used as sensing elements to detect substances dissolved in liquids and gases. Dyes do not react with liquids in which dissolved, but do respond to changes in chemical compositions by changing color. Concentration determined visually by comparison of color with predetermined standard chart, or spectrophotometrically.
Harris, J. Milton↗
Acoustically based fetal heart rate monitor
The acoustically based fetal heart rate monitor permits an expectant mother to perform the fetal Non-Stress Test in her home. The potential market would include the one million U.S. pregnancies per year requiring this type of prenatal surveillance. The monitor uses polyvinylidene fluoride (PVF2) piezoelectric polymer film for the acoustic sensors, which are mounted in a seven-element array on a cummerbund. Evaluation of the sensor ouput signals utilizes a digital signal processor, which performs a linear prediction routine in real time. Clinical tests reveal that the acoustically based monitor provides Non-Stress Test records which are comparable to those obtained with a commercial ultrasonic transducer.
Baker, Donald A.↗
Preliminary findings of the LDEF Materials Special Investigation Group
The retrieval of NASA's LDEF from low Earth orbit provided an opportunity for the study of long duration space environmental effects on materials. The five year, nine month flight of the LDEF greatly enhanced the potential value of most LDEF materials. NASA recognized this potential by forming the LDEF Space Environmental Effects on Materials Special Investigation Group (MSIG). Its goal is to explore the expanded materials analysis opportunities available in the LDEF structure and on experiment trays. The charter and scope of MSIG activities is presented, followed by an overview of the preliminary MSIG observations. These observations of low Earth orbit environmental effects on materials were made in-space during LDEF retrieval and during LDEF tray disintegration. Also presented are initial findings of lab analyses of LDEF materials. Included are effects of individual environmental parameters: atomic oxygen, ultraviolet radiation, meteoroid and debris impacts, thermal cycling, vacuum, and contamination, plus combined effects of these parameters. Materials considered include anodized aluminum, polymer matrix composites, polymer films, silvered Teflon thermal blankets, and a white thermal control paint.
Stein, Bland A.↗