Search NASA⌕ Search

SEARCH · Search NASA

Results for “PLASTIC COATING”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 records

The M-band transmission flux of the plastic foil with a coated layer of silicon or germanium

Silicon (Si) and Germanium (Ge) can be used as the dopant in the ablator material for the purpose of reducing preheating in indirect-drive inertial confinement fusion. Their performances in reducing preheating are quite different. A method to evaluate the difference of these two kinds of dopants has been presented in this letter. In the Shenguang-II high power laser facility, the M-band (1.6–4.4 keV) transmission flux of Si-coated plastic (CH) and Ge-coated plastic (CH) has been measured by using the M-band x-ray diode. In the experiment, we find that the Si-coated CH can absorb more M-band x-rays and thus reduce the preheating of the fuel in our experiment condition. By using the radiation hydrodynamic code MULTI-1D, we got the simulation result which was well suited for the experiment. The comparison of their opacities (T{sub e} = 60–100 eV and ρ = 0.1–0.5 g/cm{sup 3}) also shows that the opacity of Si is higher than that of Ge almost in the whole range of 1.6–4.4 keV.

36 MATERIALS SCIENCE↗

Role of Carbon Bridge Length of Organosilicate Precursors on the Atmospheric Plasma Deposition of Transparent Bilayer Protective Coatings on Plastics

Here, we demonstrate the deposition of transparent organosilicate protective bilayer coatings on poly methyl methacrylate (PMMA) substrates with different carbon chain length dipodalsilane precursors using atmospheric plasma deposition in ambient air. The bottom adhesive layer was a hybrid organosilicate coating deposited using either only carbon bridge organosilicate precursor or accompanied with a ring structure 1,5-cyclooctadiene precursor. The top layer was a dense silica coating with high elastic modulus and hardness deposited with only carbon bridge precursor. The adhesion energy of bottom layer increased with increasing carbon bridge length of precursors while the density, hardness, and elastic modulus of top hard layer decreased. The deposited bilayer structure showed ~3 times the adhesion energy and four times the elastic modulus of commercial polysiloxane sol–gel coatings.

36 MATERIALS SCIENCE↗

Thermodynamic Properties of Aggregate Coated by Different Types of Waste Plastic: Adhesion and Moisture Resistance of Asphalt-Aggregate Systems

The utilization of acidic aggregates in hot-mix asphalt (HMA) is often inevitable due to the limited supply of locally available aggregates, posing a potential threat of moisture damage to asphalt pavements. In this regard, the use of urban waste plastic to coat the low-quality aggregates is a promising way to improve the moisture resistance. This study fundamentally evaluated the compatibility between asphalt and plastic-coated aggregate by measuring surface energy, and for the first time compared the effects of different types of waste plastic including high-density polyethylene (HDPE), low-density polyethylene (LDPE), polyethylene terephthalate (PET), polyvinyl chloride (PVC), and polypropylene (PP). The plastic-coating significantly altered the chemistry of aggregate surface by increasing the nonpolar components and reducing the polar components. Such changes remarkably increased the dry adhesion energy between asphalt and aggregate and enhanced the wettability of aggregate. For the acidic aggregates, the polymeric treatment could decrease the value of wet adhesive, which indicated the debonding tendency in the presence of water was reduced. Finally, the energy ratios of the asphalt-aggregate combinations significantly increased by the surface pretreatment, which proved the effect of waste plastic coating on improving the moisture damage resistance of asphalt mixtures. By comparison, the HDPE coating was the most effective way to enhance the compatibility with asphalt, followed by PP and LDPE coatings. The PVC and PET coatings were investigated as the least effective way. In conclusion, this study cannot only contribute to the potential large-scale utilization of waste plastic but also remove the obstacles of using large quantities of acidic natural aggregate in asphalt pavements.

36 MATERIALS SCIENCE↗

A simple method for the measurement of reflective foil emissivity

Reflective metal foil is widely used to reduce radiative heat transfer within the roof space of buildings. Such foils are typically mass-produced by vapor-deposition of a thin metallic coating onto a variety of substrates, ranging from plastic-coated reinforced paper to 'bubble-wrap'. Although the emissivity of such surfaces is almost negligible in the thermal infrared, typically less than 0.03, an insufficiently thick metal coating, or organic contamination of the surface, can significantly increase this value. To ensure that the quality of the installed insulation is satisfactory, Australian building code AS/NZS 4201.5:1994 requires a practical agreed method for measurement of the emissivity, and the standard ASTM-E408 is implied. Unfortunately this standard is not a 'primary method' and requires the use of specified expensive apparatus and calibrated reference materials. At NMIA we have developed a simple primary technique, based on an apparatus to thermally modulate the sample and record the apparent modulation in infra-red radiance with commercially available radiation thermometers. The method achieves an absolute accuracy in the emissivity of approximately 0.004 (k=2). This paper theoretically analyses the equivalence between the thermal emissivity measured in this manner, the effective thermal emissivity in application, and the apparent emissivity measured in accordance with ASTM-E408.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Leaching and Biodegradation of Darocur 1173 used as a Photo-Initiator in the Production of Photocrosslinked Silicone Acrylates

Photocrosslinked silicone acrylates are used for a wide variety of applications, such as photocurable coatings, printing inks and adhesives. Their production requires the use of a photoinitiator (PI), such as Darocur 1173 (2-hydroxy-2-methyl-1-phenyl-propan-1-one). Even if PI represents a minor part of the formulation, residual amounts may remain in the polymerized products and possibly migrate into the environment during the use of the end products and/or at their end-of-life stage. To assess its possible fate under different environmental conditions, the release of Darocur 1173 from photocrosslinked silicone acrylates and its biodegradation were investigated. Leaching tests in water were conducted on thick coating and thin coated plastic films. Results showed that approximately 90% of the amount of Darocur 1173 used to synthesize thick coatings was released within 8 days of experiment. Biodegration assays were also done to assess the biodegradation of silicone coatings and PI under experimental conditions simulating the products’ end-of-life in sewage treatment plants (aerobic conditions) or in domestic waste landfills (anaerobic conditions). Results showed no biodegradation of thick coatings and PI under anaerobic conditions. An inhibitory effect was even observed on the biodegradation of glucose used as a reference biodegradable molecule. Under aerobic conditions however, PI was totally biodegraded and used as a carbon source, unlike the silicone coating which was not biodegraded.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Transforming the Chemical Industry

There are huge reservoirs of oil in the deep waters of the Gulf of Mexico. A major oil company is now retrieving that oil safely, despite huge challenges—oil leaves the seabed at boiling hot temperatures, through 7,000 feet of steel pipe exposed to corrosive saltwater at temperatures near freezing. An extra margin of safety comes from a specialized plastic coating on the pipe that both insulates and protects the pipe: it can cope with oil as hot as 390º. The special plastic is made from chains of carbon-based molecules (called polymers) that do not occur in nature. Rather they are the result of a powerful chemical process developed over decades of research by two university scientists—research supported by the Basic Energy Sciences (BES) office of DOE and other federal agencies—for which they were both awarded a Nobel Prize. That process expanded the chemical industry’s toolset, enabling many new products as well as more efficient production processes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Self-powered p-NiO/n-ZnO heterojunction ultraviolet photodetectors fabricated on plastic substrates

A self-powered ultraviolet (UV) photodetector (PD) based on p-NiO and n-ZnO was fabricated using low-temperature sputtering technique on indium doped tin oxide (ITO) coated plastic polyethylene terephthalate (PET) substrates. The p-n heterojunction showed very fast temporal photoresponse with excellent quantum efficiency of over 63% under UV illumination at an applied reverse bias of 1.2 V. The engineered ultrathin Ti/Au top metal contacts and UV transparent PET/ITO substrates allowed the PDs to be illuminated through either frontside or backside. Morphology, structural, chemical, and optical properties of sputtered NiO and ZnO films were also investigated.

36 MATERIALS SCIENCE↗

Structural Emergence in Particle Dispersions

Particle dispersions, such as pigment-based inks, comprise weakly bound, milled nanoparticles. The properties of these pigments depend on both their chemical composition and a rather complex structural hierarchy which emerges from these dispersions. The emergence of structure under semidilute conditions is related to the structure of the dilute particles, the particle spacing (mesh size), processing history, and the interaction potential. Kinetic simulations could predict such emergence using these input parameters. In this paper, organic pigments are studied as an example of the importance of emergent structure to predict properties such as brilliance and opacity. Organic pigments are used to impart color to commercial inks, plastics, coatings, and cosmetics. In many cases, dilute pigments are mass fractal structures consisting of aggregated nanoparticles held together by weak van der Waals forces. In water, surfactant is added to create a pigment dispersion (an ink). The final properties of a pigment emerge from a complex interplay between aggregation and dispersion of aggregates as a function of concentration. Samples of the organic pigment yellow 14, PY14, were milled to four primary particle sizes to study the effect on structural emergence. The interaction between surfactant-stabilized PY14 aggregates in an aqueous medium was quantified by the second virial coefficient, A 2 , which reflects long-range interactions. The degree of aggregation is associated with short-range attractive interactions between primary particles. In this series of pigments, the degree of aggregation increases dramatically with reduction in primary particle size. Concurrently, the second-order virial coefficient, A 2 , increases reflecting stronger long-range repulsive interactions with particle size. Structural emergence can be understood through the percolation concentration and the filler mesh size. A 2 is translated into a repulsive interaction potential for use in dissipative particle dynamics simulations to enable predictive modeling. Furthermore, this description of the interactions between dispersed pigment aggregates allows for a more scientific and predictive approach to understand structural emergence.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Instrument for evaluating the electrical resistance and wavelength-resolved transparency of stretchable electronics during strain

A complete analysis of strain tolerance in a stretchable transparent conductor (TC) should include tracking of both electrical conductivity and transparency during strain; however, transparency is generally neglected in contemporary analyses. In this paper, we describe an apparatus that tracks both parameters while TCs of arbitrary composition are deformed under stretching-mode strain. We demonstrate the tool by recording the electrical resistance and light transmission spectra for indium tin oxide-coated plastic substrates under both linearly increasing strain and complex cyclic strain processes. The optics are sensitive across the visible spectrum and into the near-infrared region (∼400-900 nm), and without specifically optimizing for sampling speed, we achieve a time resolution of ∼200 ms. In our automated analysis routine, we include a calculation of a common TC figure of merit (FOM), and because solar cell electrodes represent a key TC application, we also weigh both our transparency and FOM results against the solar power spectrum to determine “solar transparency” and “solar FOM.” Finally, we demonstrate how the apparatus may be adapted to measure the basic performance metrics for complete solar cells under uniaxial strain.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Alternative low cost electrodes for hybrid flow batteries

An electrode for use in an all-iron redox flow battery is provided. In one example, the electrode may include a plastic mesh; and a coating on the plastic mesh. The coating may be a hydrophilic coating or a conductive coating and the electrode may have an electrode reaction potential is less than 0.8V. Further, a method of manufacturing a coated plastic mesh electrode for use in an all-iron redox flow battery is provided. In one example method, the steps include fabricating a plastic mesh, treating the plastic mesh by applying a solvent treatment or a plasma treatment or a mechanical abrasion treatment; coating the plastic mesh with a material selected from: carbon inks, metal oxides, and hydrophilic polymers.

Evans, Craig E.↗

Investigating the Interaction between Persistent Slip Bands and Surface Hard Coatings via Crystal Plasticity Simulations

Fatigue cracks often initiate from the surface extrusion/intrusions formed due to the operation of persistent slip bands (PSBs). Suppression of these surface topographical features by hard surface coatings can significantly extend fatigue lives under lower stress amplitudes (i.e., high cycle fatigue), while cracks initiate early in the coating or in the coating–substrate interface under higher stress amplitudes (i.e., low cycle fatigue), deteriorating the fatigue performance. However, both beneficial and detrimental effects of the coatings appear to be affected by the coating–substrate material combination and coating thickness. A quantitative understanding of the role of these factors in the fatigue performance of materials is still lacking. In this study, crystal plasticity simulations were employed to elucidate the dependence of the coating’s effects on two factors—i.e., the coating thickness and loading amplitudes. The results revealed that the thicker coatings more effectively suppress the operation of the PSBs, but generate higher tensile and shear stresses, normal and parallel to the interfaces, respectively, promoting interfacial delamination. The tensile stresses parallel to the interface within the coating, which favors coating fracture, are not sensitive to the coating thickness.

36 MATERIALS SCIENCE↗

Plastic Laminate Antireflective Coatings for Millimeter-Wave Optics in BICEP Array

The BICEP/Keck series of experiments target the cosmic microwave background at degree-scale resolution from the South Pole. Over the next few years, the “Stage-3” BICEP Array (BA) telescope will improve the program’s frequency coverage and sensitivity to primordial B-mode polarization by an order of magnitude. The first receiver in the array, BA1, began observing at 30/40 GHz in early 2020. The next two receivers, BA2 and BA3, are currently being assembled and will map the southern sky at frequencies ranging from 95 to 150 GHz. Common to all BA receivers is a refractive, on-axis, cryogenic optical design that focuses microwave radiation onto a focal plane populated with antenna-coupled bolometers. High-performance antireflective coatings up to 760 mm in aperture are needed for each element in the optical chain, and must withstand repeated thermal cycles down to 4 K. Here, in this work, we present the design and fabrication of the 30/40 GHz anti-reflection coatings for the recently deployed BA1 receiver, with indices matched to its various polyethylene, nylon and alumina optical components. We describe an epoxy coating technique designed for alumina optics, which achieves better than 80% transmission at room temperature. For polyethylene optical elements, we present a new heat-compression approach that allows low-density polytetrafluoroethylene AR layers to reach sub-percent reflected power. We describe the planned use of these methods for the next BA cryostats, which may inform technological choices for future small-aperture telescopes of the CMB-S4 experiment.

79 ASTRONOMY AND ASTROPHYSICS↗

Plastic Additive, Sorbent-Coated, Thermally Integrated Contactor for CO 2 Capture (PLASTIC4CO2) (Final Report)

Final report for Plastic Additive, Sorbent-Coated, Thermally Integrated Contactor for CO2 Capture (PLASTIC4CO2) DE-FE-0032132. The goal of the work was to investigate at a technology readiness level of 3 (TRL 3), the proof of concept of an additively printed plastic 2-channel heat exchanger/sorbent contactor system to achieve a 15% lower levelized cost of electricity (LCOE) than a baseline liquid phase amine adsorber system for 90% and 95% capture of CO 2 from both a 7F02 2x1CC and 7HA02 2x1CC natural gas turbines.

03 NATURAL GAS↗

Review Article: Stress in thin films and coatings: Current status, challenges, and prospects

The issue of stress in thin films and functional coatings is a persistent problem in materials science and technology that has congregated many efforts, both from experimental and fundamental points of view, to get a better understanding on how to deal with, how to tailor, and how to manage stress in many areas of applications. With the miniaturization of device components, the quest for increasingly complex film architectures and multiphase systems and the continuous demands for enhanced performance, there is a need toward the reliable assessment of stress on a submicron scale from spatially resolved techniques. Also, the stress evolution during film and coating synthesis using physical vapor deposition (PVD), chemical vapor deposition, plasma enhanced chemical vapor deposition (PECVD), and related processes is the result of many interrelated factors and competing stress sources so that the task to provide a unified picture and a comprehensive model from the vast amount of stress data remains very challenging. This article summarizes the recent advances, challenges, and prospects of both fundamental and applied aspects of stress in thin films and engineering coatings and systems, based on recent achievements presented during the 2016 Stress Workshop entitled “Stress Evolution in Thin Films and Coatings: from Fundamental Understanding to Control.” Evaluation methods, implying wafer curvature, x-ray diffraction, or focused ion beam removal techniques, are reviewed. Selected examples of stress evolution in elemental and alloyed systems, graded layers, and multilayer-stacks as well as amorphous films deposited using a variety of PVD and PECVD techniques are highlighted. Based on mechanisms uncovered by in situ and real-time diagnostics, a kinetic model is outlined that is capable of reproducing the dependence of intrinsic (growth) stress on the grain size, growth rate, and deposited energy. The problems and solutions related to stress in the context of optical coatings, inorganic coatings on plastic substrates, and tribological coatings for aerospace applications are critically examined. This review also suggests strategies to mitigate excessive stress levels from novel coating synthesis perspectives to microstructural design approaches, including the ability to empower crack-based fabrication processes, pathways leading to stress relaxation and compensation, as well as management of the film and coating growth conditions with respect to energetic ion bombardment. Future opportunities and challenges for stress engineering and stress modeling are considered and outlined.

36 MATERIALS SCIENCE↗

Enhancing the performance of solvent-borne poly(ethyl methacrylate) coatings for high-power laser applications via low-temperature drying

Organic polymers are a versatile class of materials employed in a broad range of optical coating applications. However, their use as coatings in high-power laser applications, particularly in the UV spectral region, has been limited in scope due to their relatively low laser-induced damage thresholds (LIDTs), which decrease further with exposure to multiple pulses. This study explores the effect of post-deposition drying temperature and residual solvent on the LIDT of solvent-borne polymer coatings. In this work, poly(ethyl methacrylate) (PEMA) coatings were deposited by first spin coating solutions of PEMA (dissolved in 2,2,2-trichloroethanol (TCE)) onto fused silica substrates, then baking at temperatures of either 130°C (soft-bake) or 180°C (hard-bake). Analysis of the two coatings revealed that the soft-bake coating retained a significant amount of TCE within the polymer matrix, which functioned to plasticize the coating and reduce internal stress. The laser-induced damage resistance of the two coatings was evaluated using 351-nm, 1-ns laser pulses. The testing protocols included single-pulse (1-on-1), 1-pulse ramp (R-on-1), and a 1000-pulse ramp (1000R-on-1) test. The results showed that the plasticized, soft-bake coating exhibits a significantly increased LIDT, especially for multipulse irradiation conditions.

36 MATERIALS SCIENCE↗

Using Statistical Analysis Software to Advance Nitro Plasticizer Wettability

Statistical analysis in science is an extremely powerful tool that is often underutilized. Additionally, it is frequently the case that data is misinterpreted or not used to its fullest extent. Utilizing the advanced software JMP®, many aspects of experimental design and data analysis can be evaluated and improved. This overview will detail the features of JMP® and how they were used to advance a project, resulting in time and cost savings, as well as the collection of scientifically sound data. The project analyzed in this report addresses the inability of a nitro plasticizer to coat a gold coated quartz crystal sensor used in a quartz crystal microbalance. Through the use of the JMP® software, the wettability of the nitro plasticizer was increased by over 200% using an atmospheric plasma pen, ensuring good sample preparation and reliable results.

36 MATERIALS SCIENCE↗