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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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At least 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS1995

Replacements For Ozone-Depleting Foaming Agents

Fluorinated ethers used in place of chlorofluorocarbons and hydrochlorofluorocarbons. Replacement necessary because CFC's and HCFC's found to contribute to depletion of ozone from upper atmosphere, and manufacture and use of them by law phased out in near future. Two fluorinated ethers do not have ozone-depletion potential and used in existing foam-producing equipment, designed to handle liquid blowing agents soluble in chemical ingredients that mixed to make foam. Any polyurethane-based foams and several cellular plastics blown with these fluorinated ethers used in processes as diverse as small batch pours, large sprays, or double-band lamination to make insulation for private homes, commercial buildings, shipping containers, and storage tanks. Fluorinated ethers proved useful as replacements for CFC refrigerants and solvents.

Blevins, Elana↗
NASA NTRS1982

Test methodology for evaluation of fireworthy aircraft seat cushions

Aircraft seat materials were evaluated in terms of their thermal performance. The materials were evaluated using (a) thermogravimetric analysis, (b) differential scanning calorimetry, (c) a modified NBS smoke chamber to determine the rate of mass loss and (d) the NASA T-3 apparatus to determine the thermal efficiency. In this paper, the modified NBS smoke chamber will be described in detail since it provided the most conclusive results. The NBS smoke chamber was modified to measure the weight loss of materials when exposed to a radiant heat source over the range of 2.5 to 7.5 W/cm sq. This chamber has been utilized to evaluate the thermal performance of various heat blocking layers utilized to protect the polyurethane cushioning foam used in aircraft seats. Various kinds of heat blocking layers were evaluated by monitoring the weight loss of miniature seat cushions when exposed to the radiant heat. The effectiveness of aluminized heat blocking systems was demonstrated when compared to conventional heat blocking layers such as neoprene. All heat blocking systems showed good fire protection capabilities when compared to the state-of-the-art, i.e., wool-nylon over polyurethane foam.

Kourtides, D. A.↗
NASA NTRS1982

Thermal Performance of Aircraft Polyurethane Seat Cushions

Aircraft seat materials were evaluated in terms of their thermal performance. The materials were evaluated using (a) thermogravimetric analysis, (b) differential scanning calorimetry, (c) a modified NBS smoke chamber to determine the rate of mass loss and (d) the NASA T-3 apparatus to determine the thermal efficiency. In this paper, the modified NBS smoke chamber will be described in detail since it provided the most conclusive results. The NBS smoke chamber was modified to measure the weight loss of material when exposed to a radiant heat source over the range of 2.5 to 7.5 W/sq cm. This chamber has been utilized to evaluate the thermal performance of various heat blocking layers utilized to protect the polyurethane cushioning foam used in aircraft seats. Various kinds of heat blocking layers were evaluated by monitoring the weight loss of miniature seat cushions when exposed to the radiant heat. The effectiveness of aluminized heat blocking systems was demonstrated when compared to conventional heat blocking layers such as neoprene. All heat blocking systems showed good fire protection capabilities when compared to the state-of-the-art, i.e., wool-nylon over polyurethane foam.

Kourtides, D. A.↗
NASA NTRS2006

Characterization of Space Shuttle Thermal Protection System (TPS) Materials for Return-to-Flight following the Shuttle Columbia Accident Investigation

During the Space Shuttle Columbia Accident Investigation, it was determined that a large chunk of polyurethane insulating foam (= 1.67 lbs) on the External Tank (ET) came loose during Columbia's ascent on 2-1-03. The foam piece struck some of the protective Reinforced Carbon-Carbon (RCC) panels on the leading edge of Columbia's left wing in the mid-wing area. This impact damaged Columbia to the extent that upon re-entry to Earth, superheGed air approaching 3,000 F caused the vehicle to break up, killing all seven astronauts on board. A paper after the Columbia Accident Investigation highlighted thermal analysis testing performed on External Tank TPS materials (1). These materials included BX-250 (now BX-265) rigid polyurethane foam and SLA-561 Super Lightweight Ablator (highly-filled silicone rubber). The large chunk of foam from Columbia originated fiom the left bipod ramp of the ET. The foam in this ramp area was hand-sprayed over the SLA material and various fittings, allowed to dry, and manually shaved into a ramp shape. In Return-to-Flight (RTF) efforts following Columbia, the decision was made to remove the foam in the bipod ramp areas. During RTF efforts, further thermal analysis testing was performed on BX-265 foam by DSC and DMA. Flat panels of foam about 2-in. thick were sprayed on ET tank material (aluminum alloys). The DSC testing showed that foam material very close to the metal substrate cured more slowly than bulk foam material. All of the foam used on the ET is considered fully cured about 21 days after it is sprayed. The RTF culminated in the successful launch of Space Shuttle Discovery on 7-26-05. Although the flight was a success, there was another serious incident of foam loss fiom the ET during Shuttle ascent. This time, a rather large chunk of BX-265 foam (= 0.9 lbs) came loose from the liquid hydrogen (LH2) PAL ramp, although the foam did not strike the Shuttle Orbiter containing the crew. DMA testing was performed on foam samples taken fiom a simulated PAL ramp panel. It was found that the smooth rind on the foam facing the cable tray did significantly affect the properties of foam at the PAL ramp surface. The smooth rind increased the storage modulus E' of the foam as much as 20- 40% over a temperature range of -145 to 95 C. Because of foam loss fiom the PAL ramp, future Shuttle flights were grounded indefinitely to allow further testing to better understand foam properties. The decision was also made to remove foam from the LH2 PAL, ramp. Other RTF efforts prior to the launch of Discovery included

Wingard, Doug↗
NASA NTRS2009

Mitigation of EMU Glove Cut Hazard by MMOD Impact Craters on Exposed ISS Handrails

Recent cut damages to crewmember extravehicular mobility unit (EMU) gloves during extravehicular activity (EVA) onboard the International Space Station (ISS) has been found to result from contact with sharp edges or pinch points rather than general wear or abrasion. One possible source of cut-hazards are protruding sharp edged crater lips from impact of micrometeoroid and orbital debris (MMOD) particles on external metallic handrails along EVA translation paths. During impact of MMOD particles at hypervelocity an evacuation flow develops behind the shock wave, resulting in the formation of crater lips that can protrude above the target surface. In this study, two methods were evaluated to limit EMU glove cut-hazards due to MMOD impact craters. In the first phase, four flexible overwrap configurations are evaluated: a felt-reusable surface insulation (FRSI), polyurethane polyether foam with beta-cloth cover, double-layer polyurethane polyether foam with beta-cloth cover, and multi-layer beta-cloth with intermediate Dacron netting spacers. These overwraps are suitable for retrofitting ground equipment that has yet to be flown, and are not intended to protect the handrail from impact of MMOD particles, rather to act as a spacer between hazardous impact profiles and crewmember gloves. At the impact conditions considered, all four overwrap configurations evaluated were effective in limiting contact between EMU gloves and impact crater profiles. The multi-layer beta-cloth configuration was the most effective in reducing the height of potentially hazardous profiles in handrail-representative targets. In the second phase of the study, four material alternatives to current aluminum and stainless steel alloys were evaluated: a metal matrix composite, carbon fiber reinforced plastic (CFRP), fiberglass, and a fiber metal laminate. Alternative material handrails are intended to prevent the formation of hazardous damage profiles during MMOD impact and are suitable for flight hardware yet to be constructed. Of the four materials evaluated, only the fiberglass formed a less hazardous damage profile than the baseline metallic target. Although the CFRP laminate did not form any noticeable crater lip, brittle protruding fibers are considered a puncture risk. In parallel with EMU glove redesign efforts, modifications to metallic ISS handrails such as those evaluated in this study provide the means to significantly reduce cut-hazards from MMOD impact craters.

Christiansen, Eric L.↗
DOE OSTI2020

Investigation of Polyurethane and Fire-Retardant Foams as a Radiological Contamination Fixatives - 20202

Fixation of radiological contamination in decommissioning and deactivation can reduce worker risk, and mitigate potentially hazardous conditions; however, nearly every marketed contamination fixative has been found to be flammable, a significant concern in radiological facilities. Coupled with this, industry fixatives are normally used as a thin coating which can present problems when attempting to stabilize irregular void spaces or areas that are difficult to access and ensure full coverage. To this end, Savannah River National Laboratory (SRNL), in conjunction with Florida International University (FIU), have begun investigating the applicability of polyurethane based foaming materials, which will expand to fill a given asymmetric volume and provide fire retardancy to ensure no release of contamination in the event of a facility fire. Commercial foams undergo exothermic reactions resulting in gaseous release that subsequently causes the curing foam material to expand. Heat generation during curing can potentially compromise rubber parts of an enclosure, a significant concern in nuclear facilities. To mitigate large body heat generation, SRNL has also examined multiple layering of the material to ensure compatibility of the curing material with a previously cured body of the same material. Environmental studies were also completed in order to determine the influence on polyurethane based foams curing process. These studies showed that nearly half of the materials tested delaminated from a cured body of the same material, a property not discussed in commercially available documentation on the products. Of note was the compatibility of the foaming material with the substrate, depending on the type material that the foam was cured in/on, significant delamination could occur. Mechanical testing via tensile pull tester, dynamic mechanical analysis (DMA), and thermogravimetric analysis (TGA) was also performed. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2022

A Novel Process for Converting Coal to High-Value Polyurethane Products

Battelle has demonstrated a patented process for making high-value, polyurethane (PU) foam from coal, based on preparing liquefied coal via direct liquefaction, converting it to polyols as an intermediate via ozonation, and then making PU foams from these polyols. This process represents a breakthrough in innovative utilization of U.S. coals, and is applicable to bituminous as well as sub-bituminous coals. The resulting PU foam products are projected to have an extremely high value (i.e., over $\$5,000$ /ton), with nearly 100% of carbon utilization from coalderived liquid feedstock, and 31.5% to 43.5% of the carbon in the PU foam polyol product being bio-based. The targeted products represent an extremely large (i.e., over $80 billion/year), existing PU foam market, which could expand into making coatings and adhesives. The process can further help reduce petroleum imports, while improving the economics of PU foam production. This work was completed with funding from the National Energy Technology Laboratory (NETL), with cost share from the State of Ohio’s Ohio Development Services Agency (ODSA) and others, and has advanced the process to 10 kg/day continuous scale and thus to Technology Readiness Level (TRL) 5. A total of 48 coal-based polyols were prepared and evaluated. The initial 28 polyols focused on range finding for ideal conditions. The later 20 polyols were produced as part of process optimizations. These optimizations were targeted around a continuous ozonolysis process to evaluate extended time reactions and to create the necessary intermediate for production of 1-gallon samples of polyol. The most unique attribute of Battelle’s polyol is in the utilization of coal’s aromaticity to gain final foam rigidity. Typically, polyols depend on the isocyanate fraction and cross-linking to gain rigidity. By utilizing coal, we were able to maintain rigidity while reducing the overall hydroxyl value of the polyol. This is important as lower hydroxyl value leads to greater percent weight of the coal-based polyol because less isocyanate is required for foaming. This leads to greater foam cost savings. This report provides the details, process, and process cost models of the conversion of coal to polyols and further to PU foams. Battelle’s process begins with coal liquids. These liquids can be obtained by two processes: coal coking or pyrolysis to produce coal tar, and Battelle’s biobased coal-to-liquids (CTL) process to produce heavy syncrude after liquifying >85% coal. After liquification, Battelle utilizes ozonolysis to create functionalization on the polyaromatic coal structure. The functionalization is then converted to the final polyester polyol through transesterification, or to hydroxyamide polyol through amidification. Equivalent or better standard properties have been obtained for 2 lb/ft 3 density rigid, water and freon-alternative blown foams, including compressive strength, density, R-value, and dimensional stability. Target applications for these foams are insulation, packaging, and energy-absorbing foams. Some exploratory testing also showed promise for adhesives applications. A detailed economic analysis showed that Battelle’s polyol process is economical, at a 140 metric tons per day (MTD) polyol production scale. An attractive return on investment (ROI) at competitive pricing validates the process is ready for a pilot-plant demonstration. A scale-up plan is provided.

01 COAL, LIGNITE, AND PEAT↗
NASA NTRS1971

The performance of lightweight plastic foams developed for fire safety

The use of a low density, polyurethane based foam to suppress a fire and to provide protection for the structure of an aircraft or spacecraft is discussed. The mechanism by which foams provide protection from heat and create a nonflammable surface is described. Various materials and their application to specific types of structures are examined.

Fish, R. H.↗
DOE OSTI2026

Develop Renewable/Sustainable Material to Displace Petroleum-Derived Polymer Foams (CRADA Final Report)

NLR and EDEN will partner together to develop renewable, biodegradable alternatives to polyfoam (polyurethane) polymer foams. The initial focus will be on developing cellulose-based foam with tunable mechanical properties. NLR will produce and test the cellulose-based foam materials and characterize its microstructure and mechanical properties. Relationships between mechanical performance formulation and fabrication methods will be developed.

09 BIOMASS FUELS↗
NASA NTRS2015

Cryoinsulation Material Development to Mitigate Obsolescence Risk for Global Warming Potential Foams

Cryoinsulation foams currently being qualified for the Space Launch System (SLS) core stage are nonozone- depleting substances (ODP) and are compliant with current environmental regulations. However, these materials contain the blowing agent HFC-245fa, a hydrofluorocarbon (HFC), which is a Global Warming Potential (GWP) substance. In August 2014, the Environmental Protection Agency (EPA) proposed a policy change to reduce or eliminate certain HFCs, including HFC-245fa, in end-use categories including foam blowing agents beginning in 2017. The policy proposes a limited exception to allow continued use of HFC and HFC-blend foam blowing agents for military or space- and aeronautics-related applications, including rigid polyurethane spray foams, but only until 2022.

Protz, Alison↗
DOE OSTI2020

Mechanical Properties of Permanent Foaming Fixatives for Deactivation and Decommissioning Activities

DOE-EM have identified an operational requirement for a fixative that can immobilize and/or encapsulate residual contamination in 3D void volumes (pipes, gloveboxes, waste containers, etc.) during D and D activities. Failure to safely and effectively immobilize residual contamination can: Put workers at risk, Contaminate the public and environment, Drive up operational costs. Commercial-off-the-shelf (COTS) polyurethane (PU) foams is one possible solution and is currently being investigated in collaboration with Savannah River National Lab (SRNL). Mechanical property testing will dictate how well PU foams can withstand physical stressors outlined in safety documents while immobilizing residual contamination. Results can provide a performance criteria for Section 5 of ASTM E3191: Standard Specification for Permanent Foaming Fixatives Used to Mitigate Spread of Radioactive Contamination. Polyurethanes consists of repeating units of urethanes which are produced from an exothermic reaction between a polyol (an alcohol with two or more hydroxyl groups in a molecule) and an isocyanate [2]. PUs consists of 3D cells that are formed by a blowing agent which is normally water. Water interacting with the isocyanate creates carbon dioxide and urea which contributes to cells' growth and expansion. The cross-linking between the polyol and isocyanate solidify the cell faces and walls. Micro scale properties that can influence mechanical properties include: Relative density (ratio between density of cellular material and density of the solid of which the cell walls are made of). Cells connectivity between edges and faces, and number of cells contact neighbors [3]. Whether a foam is open-celled or closed-celled. Closed-celled foams have a thin membrane that encloses each cell which can contribute to the stiffness of the foam. Incorporating fillers in the PU matrix like carbon-based nanoparticles in the form of expandable graphite (EG) can increase the thermal and mechanical performance [4]. When exposed to heat, EG produces a char layer that prevents heat and oxygen transfer which is known as intumescing. Mechanical performance is dependent on amount of EG loading since the cell sizes are linearly dependent on it. Overall, the rigid foams (I-R2) proved superior. SEM Analysis: I-R2 had the most consistent spherical sizes (average cell diameter: 489 μm), which enhance the relative density the most [5]. Tensile Testing Results: I-R2 experienced the largest breaking load (103.65 lbf) and stress (289.42 psi). I-R2 also had a higher Young's Modulus compared to R1 (2.99 ksi to 2.09 ksi). Compression Testing Results: I-R2 had the highest stress at 80% deflection (360.67 psi), load (1387.48 lbf) and modulus (3.92 ksi)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
NASA NTRS1967

Polymer research

Stress-strain distribution in elastomers, and chemical and physical properties of prepolymers, rigid urethane foam, and thermoplastic rubbers for composite solid propellant binders

ELASTOMER↗
DOE OSTI2020

Adhesion Capabilities of Permanent Foaming Fixatives

DOE-EM have identified an operational requirement for a fixative that can immobilize and/or encapsulate residual contamination in 3D void volumes (pipes, gloveboxes, waste containers, etc.) during D and D activities. Failure to safely and effectively immobilize residual contamination can: Put workers at risk; Contaminate the public and environment; Drive up costs. Commercial-off-the-shelf (COTS) polyurethane (PU) foams is one possible solution and is currently being investigated by Savannah River National Lab (SRNL). Adhesion testing will dictate how well PU foams will adhere and immobilize residual contamination onto a substrate. Results can provide a performance criteria for Section 5 of ASTM E3191: Standard Specification for Permanent Foaming Fixatives Used to Mitigate Spread of Radioactive Contamination. Initial mechanical testing showed intumescent rigid PU foams were best in class (tensile, compression, TGA/DSC) Application of intumescent rigid PU foam in pipe scenario with 'contamination' showed excellent adhesion capabilities as long as foam had contact with pipe. The foam, however, was not able to penetrate 'contamination' but created pockets where the contamination interacted with the substrate. Pretreatment options of pipe were considered to produce better immobilization capabilities. Pretreatment options included COTS products like baking spray, rubber cement, and soap. Foam was still able to immobilize on a global sense, but not a local sense. Essentially acted as a mechanical plug. A tensile tester (MTS Criterion Series 43) was utilized to evaluate the tensile adhesion strength of 6 COTS PU foams. ASTM D1623: Tensile and Tensile Adhesion Properties of Rigid Cellular Plastics. Procedures: PU foams were cured between two smooth 2'' x 2'' 304 stainless steel coupons with hinges glued on plates for gripping support. Parameters Used: Pull rate of 0.1 in/min. Calculations: Tensile adhesion strength, elongation, and ImageJ analysis of how PU foam is left on substrate. Outcome: The PU foam with the best adhesion capabilities would be downselected for further evaluation to be used as a permanent foaming fixative. The rigid PU foams had the best adhesion capabilities with the R1 foam having a max load of 236 N. One of the I-R2 samples reached almost 450 N and another sample reached 2500 N before slipping. The other intumescent foam, I-F4, had the most coverage on the stainless steel coupon's surface from the ImageJ results (61.43% surface coverage). The intumescent foam, I-R2, will be the foam of choice for future testing due its fire retardant and adhesion capabilities. Future directions: Conduct the following experiment in a pipe scenario with the down-selected PU foam. Procedures: PU foam will be cured between in a 304 stainless steel pipe (ID: 4'', OD: 4.5'', Height: 4''). Parameters Used: Compression testing results will be referenced to determine if foam's adhesion strength would be greater its compression strength as its being compressed. Calculations: Compression strength, shear stress, total time elapsed. Conduct further adhesion testing with the down-selected PU foam (I-R2) to be treated as a permanent foaming fixative (PFF). Determine the minimum contact the PFF should have with the substrate for adequate results. Evaluate if PFF's adhesion capabilities is time dependent (3.1.5 of ASTM E3911). Subject PFF to seismic stressors addressed in Safety Basis of Interim Operation documents (SBIO) to further evaluate adhesion capabilities.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
NASA NTRS2002

Deployment, Foam Rigidization, and Structural Characterization of Inflatable Thin-Film Booms

Detailed investigation of the construction, packaging/deployment, foam rigidization, and structural characterization of polyimide film inflatable booms is described. These structures have considerable potential for use in space with solar concentrators, solar sails, space power systems including solar arrays, and other future missions. Numerous thin-film booms or struts were successfully constructed, inflated, injected with foam, and rigidized. Both solid-section and annular test articles were fabricated, using Kapton polyimide film, various adhesives, Styrofoam end plugs, and polyurethane pressurized foam. Numerous inflation/deployment experiments were conducted and compared to computer simulations using the MSC/DYTRAN code. Finite element models were developed for several foam-rigidized struts and compared to model test results. Several problems encountered in the construction, deployment, and foam injection/rigidization process are described. Areas of difficulty included inadequate adhesive strength, cracking of the film arid leakage, excessive bending of the structure during deployment, problems with foam distribution and curing properties, and control of foam leakage following injection into the structure. Many of these problems were overcome in the course of the research.

Schnell, Andrew R.↗
DOE OSTI2026

Minimized aging of isocyanurate-based rigid cellular foams for buildings through tailored barrier facers and optimized formulation

The thermal resistivity (h·ft 2 ·°F/Btu/in.) of closed-cell rigid foam insulation materials significantly decreases over time. Diffusion-tight facers are designed to significantly enhance initial thermal resistivity and long-term thermal performance by preventing gas diffusion into the foam cells and inhibiting the escape of low thermal conductivity blowing agents. In addition to the gas diffusion property of the facer film, adhesion between the foam and the facer is crucial for achieving diffusion-tight bonding. Here, this study addresses the challenge of thermal aging by investigating how facer film properties and foam formulation influence the durability of thermal performance. A systematic evaluation was conducted to understand the effects of polymeric barrier films, surface treatments, facer coverage, and foam matrix rigidity on thermal resistivity over time. Key findings reveal that diffusion-tight facers, particularly those with metallized layers and compatible heat seal layers, significantly reduce gas exchange and improve foam-facer adhesion. The optimized system, incorporating barrier facers and a tailored polyisocyanurate foam formulation, achieved initial and aged thermal resistivity values after 200 days of approximately 8.3 and 7.4 h ft 2 ·°F/Btu/in., respectively representing only a 10 % reduction compared to a 17 % reduction observed in control samples without facers. Notably, polyurethane spray foams with facers exhibited only a 4 % reduction in thermal resistivity, compared to a 23 % decrease in control samples, demonstrating nearly six times better retention of thermal performance. This innovative facer technology presents a promising solution for reducing energy costs and represents a significant advancement in optimizing energy management for building envelopes in future technologies. This technology can also be adapted for other applications that necessitate the preservation of long-term thermal performance.

Wanasinghe, Shiwanka Vidarshi [Oak Ridge National ↗