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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 973 records · Page 54
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Surface modification of polymer foams using plasma

An embodiment includes a system comprising: a monolithic shape memory polymer (SMP) foam having first and second states; wherein the SMP foam includes: (a) polyurethane, (b) an inner half portion having inner reticulated cells defined by inner struts, (c) an outer half portion, having outer reticulated cells defined by outer struts, surrounding the inner portion in a plane that provides a cross-section of the SMP foam, (d) hydroxyl groups chemically bound to outer surfaces of both the inner and outer struts. Other embodiments are discussed herein.

Nash, Landon D.↗
DOE OSTI2024

Process Optimization of Carbon Electrode Materials Manufacturing by Experimental Study and Machine Learning Techniques

Electrospun carbon fibers from coal have been investigated as electrodes for batteries and supercapacitors. Despite the excellent properties of coal-derived carbon fibers (CCNF) for energy storage devices, there still lacks systematic understanding on how various process parameters affect final electrode performances, which poses challenges to scale from pilot to high volume manufacturing. The goals of this project are twofold. First, we focuse on process optimization for converting a new precursor from powder river basin (PRB) coal, referred to as coal-based polyurethane (CPU) to CCNF using electrospinning. Second, different machine learning techniques will be examined using experimental data from this work and open literature. Specifically, for CPU the following process parameters need to be characterized and optimized in order to produce CCNFs with desirable mechanical integrity and physiochemical properties: precursor composition and viscosity, operating voltage and distance, oxidation and carbonization temperature and duration. Consequently, physiochemical properties of the fibers were characterized to correlate these process parameters with desirable electrochemical performance. Given the complex nature of the fiber production process, ML models are assessed for their ability to capture the nonlinear relationship between process parameters and the electrochemical properties in applications including supercapacitors. As such, we applied various machine learning techniques, to determine which technique produces a model that best predicts device function.

Cincotta, Robert E.F.↗
DOE OSTI2025

Mechanical Properties and Interfacial Bonding of Overmolded Polymer Composite Lattice Structures

This study investigates the mechanical properties and interfacial bonding of Polyamide 12 filled with Glass Fiber (PA12/GF) lattice structures overmolded with Nylon 66 (PA66) and Thermoplastic Polyurethane (TPU). The PA12/GF lattices, designed in Gyroid, Isotruss, and Octahedral geometries, were produced using the Selective Laser Sintering (SLS) technique. The thermal characteristics of both the lattice and overmolding materials were analyzed using Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). The mechanical performance and interfacial bonding were evaluated through mechanical testing and microstructural analysis. The results indicate that overmolding improved flexural strength and impact resistance of the PA12/GF lattices. For instance, the plain PA12/GF Isotruss lattice exhibited a flexural strength of 15.5 MPa. By overmolding it with TPU the flexural strength increased by up to 137%, while PA66-overmolding resulted in an increase of 371%, achieving a flexural strength of 73 MPa. In terms of impact resistance, TPU-overmolding improved performance significantly, with an increase of 1800% (Gyroid) compared to the plain lattice. Microstructural analysis revealed good adhesion at the interface, especially when both the lattice and overmolding materials were thoroughly dried prior to the overmolding process to minimize interfacial porosity. This study highlights the potential of using overmolding to enhance lattice structures performance, offering lightweight and cost-efficient solutions for automotive applications.

Talabi, Isaac [ORNL] (ORCID:0000000340215594)↗
DOE OSTI2025

Synthesizing, Compounding, and Characterizing a Heat Labile Foam (SRNL-STI-2025-00653)

Degradable polyurethane foams can be an attractive material to use for packaging, transporting, and dispositioning of nuclear materials. This LDRD project explored the possibility of finding a suitable polyol component that would achieve the intended results. Significant improvements were made on the initial findings of a three month Visiting Faculty Program.

Kranjc, Mark D. [Savannah River National Laborator↗
DOE OSTI2017

Stretchable Lithium-Ion Batteries Enabled by Device-Scaled Wavy Structure and Elastic-Sticky Separator

Fast developments and substantial achievements have been shaping the field of wearable electronic devices, resulting in the persistent requirement for stretchable lithium-ion batteries (LIBs). Despite recent progress in stretchable electrodes, stretching full batteries, including electrodes, separator, and sealing material, remains a great challenge. Here, a simple design concept for stretchable LIBs via a wavy structure at the full battery device scale is reported. All components including the package are capable of being reversibly stretched by folding the entire pouch cell into a wavy shape with polydimethylsiloxane filled in each valley region. In addition, the stretchable, sticky, and porous polyurethane/poly(vinylidene fluoride) membrane is adopted as a separator for the first time, which can maintain intimate contact between electrodes and separator to continuously secure ion pathway under dynamic state. Commercial cathode, anode, and package can be utilized in this rationally designed wavy battery to enable stretchability. The results indicate good electrochemical performances and long-term stability at repeatable release–stretch cycles. A high areal capacity of 3.6 mA h cm -2 and energy density of up to 172 W h L -1 can be achieved for the wavy battery. The promising results of the cost-effective wavy battery with high stretchability shed light on the development of stretchable energy storages.

25 ENERGY STORAGE↗
DOE OSTI2019

Structural, mechanical, and antibacterial features of curcumin/polyurethane nanocomposites

Various types of bacteria inhabit many surfaces thus causing problems which can have very strong impact on human health. Here we present a study of photophysical, mechanical, and antibacterial properties of curcumin/polyurethane nanocomposites prepared by swell-encapsulation-shrink method. The prepared nanocomposites have been characterized for degree of swelling, surface morphology, mechanical properties, chemical contents, photoluminescence, hydrophobicity, potentials for singlet oxygen generation, and antibacterial activity. Dynamic mechanical analysis has shown slight changes of glass temperature of curcumin/polyurethane nanocomposites due to blue light irradiation. It was found that nanocomposites have very strong photoluminescence, become photoactive upon blue light irradiation at 470 nm and generate singlet oxygen. Conducted antibacterial tests have shown very strong activity of these nanocomposites especially toward Escherichia coli. These bacteria strains have been eliminated completely only after 1 h irradiation by blue light. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 47283. © 2018 Wiley Periodicals, Inc.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Fractionated and purified hybrid poplar lignins as a polyol replacement in rigid polyurethane/polyisocyanurate foams

This study introduces fractionated lignin as an innovative component in the formulation of rigid polyurethane/polyisocyanurate (PUR/PIR) foams. Low-density PUR/PIR rigid foams were prepared by replacing 80% of the petrochemical-based polyol with a hybrid poplar (HP) lignin, recovered via alkaline pretreatment, and also with a fraction of this lignin, isolated via the Aqueous Lignin Purification with Hot Agents (ALPHA) process. The as-recovered HP and ALPHA-fractionated HP lignins were characterized to determine hydroxyl content, molecular weight (Mw) distribution, and pH. Both lignin-based foams met minimum standard requirements in terms of closed cell content, compression strength, and thermal conductivity. Notably, the foams made with ALPHA-based lignin outperformed the as-recovered lignin-based foams in all measured foam properties. Moreover, the ALPHA-based foam had comparable performance to the control foam (without lignin) except for density and even surpassed the control foam in closed cell content and compressive strength. This investigation of the molecular properties of lignin suggests that significant reductions in lignin average molecular weight and polydispersity (PDI) can positively impact the properties of lignin-based rigid foams.

09 BIOMASS FUELS↗
DOE OSTI2019

Density and shrinkage as guiding criteria for the optimization of the thermal conductivity of poly(urethane)-class aerogels

We investigated the effect of gelation solvent, monomer type, and monomer concentration on the physical properties of freeze-dried poly(urethane)-poly(isocyanurate) (PUR-PIR) aerogels, with particular emphasis on their thermal conductivity. It was found that the gelation solvent considerably affects aerogel morphology and physical properties. Aerogels with the lowest thermal conductivity were obtained using a mixture of tetrahydrofuran (THF) and acetonitrile, in a 50% volume ratio. The influence on thermal conductivity of polyol and isocyanate structure and of their concentration was also investigated. Rigid precursors, phloroglucinol (POL), and an aromatic polyisocyanate based on toluene diisocyanate (Desmodur RC) yielded the lowest thermal conductivity. Our results were compared with recent work reporting on parameters that could be used as predictors of thermal conductivity and other physical properties of organic aerogels. None of these parameters were found to be satisfactory predictors of aerogel properties. For example, no systematic correlation between solvent solubility parameters and aerogel properties was observed. We also examined the role of the K-index. This index, defined as the ratio between porosity and contact angle, was shown recently to be a good predictor of the properties of polyurea aerogels. While the thermal conductivity scaled with the K-index, the scaling was different for each of the isocyanate monomers considered in our experiments. Thermal conductivity, instead, scaled well with the product of density and shrinkage of aerogels, independent of monomer type. The reasons of this dependence on shrinkage and density are discussed, and the use of these parameters to guide experimentation on other systems is discussed. Physical properties such as static and dynamic compression modulus and thermal stability of the most promising formulations were also examined.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Programmable bionanocomposite coated fertilizers for prolonged controlled release of nitrogen

Controlled-release fertilizers (CRFs) present a promising solution for alleviating food and nutrient scarcity. However, their development has been mainly hindered by both rapid and unsynchronized nutrient release and unsustainable coating materials. In this study, we address this issue by developing a new coating layer for CRFs using a programmable biopolyurethane nanocomposite. This nanocomposite is prepared from diphenylmethane diisocyanate (MDI)-functionalized bentonite nanoclay (BNT-MDI) and a biopolyol from biomass waste. The results show that the BNT-MDI-doped CRFs (BCRFs) exhibit an impressive nitrogen (N)-release longevity of approximately 120 days at a 4 wt% coating ratio, surpassing previous CRF formulations. In a 30-day snap bean cultivation study, BCRF significantly improved root length (1000%), leaf length (257%), leaf width (400%), and plant height (1400%) compared to the control. The superior performance of BCRF is attributed to the PU-nanoclay biocomposite film, with full nano-exfoliation, controllable porosity, and high crosslinking density. Furthermore, we introduce a new dynamic release mechanism and establish a quantitative relationship between the nanostructure, property, and release performance of BCRF by combining the multiplicative and diffusion models for porous materials. Finally, this study provides a theoretical framework and a straightforward methodology for designing programmable nanocomposite structures for future biobased CRFs.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Advancing biological processing for valorization of plastic wastes

We report the useful applications of plastics are as significant as the problems associated with their disposal. Current waste management strategies are ineffective at preventing the flow of plastics into landfills, wastewater treatment, and the environment. Despite the importance of recycling technologies, most plastics are used for consumables and are discarded after limited usage. Moreover, only certain plastics are recycled, and those that are generally yield lower value products. Discovering alternative routes for valorizing plastic wastes is essential. Emerging research involves the use of biocatalysts (i.e., enzymes and microorganisms) to produce valuable products like specialty polymers, biosurfactants, and drug precursors from these feedstocks. These bioprocesses commonly integrate physio-chemical pretreatments (to generate biologically reactive intermediates) and biological upgrading (to convert intermediates to products). Herein, publications that explore plastic deconstruction technologies and bioprocesses are reviewed with an emphasis on plastic waste valorization. Understanding how microorganisms metabolize the intermediates of plastic degradation and manage their inhibitory effects is a prerequisite for engineering bioprocesses. For these heterogeneous wastes, a paradigm shift from axenic cultivation of microorganisms to cultivation of microbial consortia may benefit conversion efficiency and stress resilience. Thus, a summary is provided for metabolic pathways and constituent enzymes required to synthesize biofuels, biomaterials, and chemicals from biologically reactive intermediates. Colossal challenges associated with the use of plastics as feedstocks for direct biological processing highlight the need for integrating physical, chemical, and biological technologies.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2023

Lignin-Based Low-Density Rigid Polyurethane/Polyisocyanurate Foams

In this paper, unmodified kraft softwood lignin was utilized to fully replace the petroleum-based polyol for the first time in low-density rigid polyurethane/polyisocyanurate (PUR/PIR) foam. The effects of different lignin incorporation levels (0, 25, 50, 75, and 100%) on foam properties were investigated by measuring foam’s reactivity, polyol viscosity (using a rheometer), apparent density, compression strength, closed cell content (using a gas pycnometer), thermal conductivity, fire resistance, and morphology (observed through SEM). All formulated lignin-based foams met the ASTM minimum requirements for type 1 rigid insulation foams. Remarkably, the foam made by replacing 100% of the petrochemical polyol with the commercially available kraft lignin demonstrated outstanding fire resistance performance, reducing the burn length by 127%.

09 BIOMASS FUELS↗
DOE OSTI2026

Molecular Mechanisms Underlying Surfactant-Based Plastics De-Inking

Surfactant-mediated binder removal is critical for de-inking pretreatment in plastics recycling, yet the molecular mechanisms governing surfactant performance remain poorly understood. We used all-atom (AA) and coarse-grained (CG) molecular dynamics (MD) simulations alongside alkaline surfactant washing experiments to investigate interactions between a series of surfactants and a polyether urethane (PEU) binder in solution and on a polyethylene (PE) surface. Experiments reveal a range of de-inking efficiencies, ranging from <25 to >95% depending upon surfactant headgroup charge and tail length. AA simulations reveal that charged surfactants reach stable levels of surfactant coverage, while nonionic surfactants aggregate on the binder. CG umbrella sampling calculations quantify the thermodynamics of binder desorption in water. In ∼0.25 M surfactant solutions, up to a 52% reduction in the free energy barrier is computed, with trends in good agreement (R 2 = 0.92, Pearson’s r = –0.96, Spearman’s ρ = –0.83) with experimental de-inking efficiencies. We find that charged surfactants are more effective than nonionic surfactants for de-inking and propose three regimes of surfactant de-inking processes: good de-inking occurs in surfactants that promote PEU desorption with a low radius of gyration (R g ); moderate de-inking occurs when surfactants stabilize PEU but increase R g ; poor de-inking occurs in surfactants that aggregate on the binder and promote extensive anchoring to the surface. Overall, these molecular-level insights have the potential to guide the design of surfactant formulations for plastics recycling applications.

ink removal↗
DOE OSTI2026

Dielectric properties of neutron and proton irradiated polymeric nanocomposite insulation for superconducting magnets of fusion power plants

Studies on radiation-resistant electrical insulation for superconducting magnets of nuclear fusion power plants are discussed. Metal oxide nanoparticle-incorporated organic polymer composite (MONAP) insulation films were manufactured and studied for their dielectric breakdown strength after exposure to neutrons and proton radiation at varying levels. Samples with up to 5 wt% of nanoparticles (NPs) of SiO 2 , MgO, and ZrO 2 were studied. The samples were exposed to radiation of up to 2 × 10 16 neutrons/cm 2 and 200 Mrad of protons. The addition of the nanoparticles improved the radiation resistance of the MONAP, and the performance depended on the type of NPs and the radiation exposure. Dielectric breakdown measurements at 77 K showed little degradation. Enhancement of dielectric strength was observed in some instances.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Experimental evaluation of low-pass shock isolation performance of elastomers using frequency-based Kolsky bar analyses

Elastomeric materials are used as shock isolation materials in a variety of environments to dampen vibrations and/or absorb energy from external impact to minimize energy transfer between two objects or bodies. Some applications require the shock isolation materials to behave as a low-pass mechanical filter to mitigate the shock/impact at high frequencies but transmit the energy at low frequencies with minimal attenuation. To fulfill this requirement, a shock isolation material needs to be carefully evaluated and selected with proper experimental design, procedures, and analyses. In this study, a Kolsky bar was modified with precompression (up to 15.5 kN) and confinement capabilities to evaluate low-pass shock isolation performance in terms of acceleration attenuation through a variety of elastomers. Also investigated were the effects of preload and specimen geometry on the low-pass shock isolation response.

36 MATERIALS SCIENCE↗
DOE OSTI2012

Measure Guideline: Internal Insulation of Masonry Walls

This measure guideline provides recommendations for interior insulation assemblies that control interstitial condensation and durability risks; recommendations for acceptable thermal performance are also provided. An illustrated guide of high-risk exterior details (which concentrate bulk water), and recommended remediation details is provided. This is followed by a recommended methodology forrisk assessment of a masonry interior insulation project: a series of steps are suggested to assess the risks associated with this retrofit, with greater certainty with added steps.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗