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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 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Enhanced CO 2 Adsorption Capacity in Highly Porous Carbon Materials Derived from Melamine-Formaldehyde Resin

Here, the present study explores the synthesis of N-doped carbon materials with large surface porosity using commercial melamine-formaldehyde resin as the precursor and KOH as the activator. The resin was carbonized first and then activated by KOH with varying KOH amount and activation temperature. Notably, the as-obtained sorbents display advanced porosity with the highest surface area and pore volume of 1591 m 2 /g and 0.74 cm 3 /g, respectively, along with high N content ranging from 6.43 to 18.34 wt %. Remarkably, maximum CO 2 capture amounts of 5.42 and 3.52 mmol/g were accomplished at 0 and 25 degrees C, 1 bar for as-synthesized carbons. Systematic studies point out that narrow microporosity is the major factor determining the CO 2 uptake of these carbons under ambient pressure. Furthermore, these sorbents display notable CO 2 selectivity, rapid adsorption kinetics, moderate heat of adsorption, substantial dynamic CO 2 capture capacity, and stable recyclability. These results underscore the potential of melamine-formaldehyde resin-derived N-doped porous carbon as an efficient and versatile adsorbent for CO 2 capture.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Extraction and separation of rare earth elements using LN resins in hydrochloric acid

The separation of the rare earth elements is essential for numerous scientific applications but remains a significant challenge due to the nearly identical chemical properties of the adjacent lanthanide elements. Eichrom’s LN series of extraction chromatographic resins feature organophosphorus extractants and are widely used to achieve adjacent lanthanide separations. While extensive characterization of these resins has been completed for nitric acid matrices, the use of hydrochloric acid is preferred for a variety of applications. Further, the extraction of the rare earth elements, La–Lu and Y, has been characterized on LN and LN2 resins in hydrochloric acid via batch uptake and column chromatographic studies.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2024

Mapping Structure and Rheology of pH-Responsive Resins for Low-VOC Coatings

In recent years, the paint and coatings industry has shifted away from traditional resin formulations that require high concentrations of volatile organic compounds (VOCs) to achieve the desired rheological performance and sustainability targets. One approach to eliminate or reduce VOCs in paint and coating formulations while maintaining the final performance is to disperse stimuli-responsive polymer latex particles in water. The chemistry and architecture of these particles have been engineered such that the suspension rheology changes in response to the pH changes. The particles can also be swollen with organic solvents to illicit similar rheological changes. To understand how the particle microstructure influences the observed macroscopic properties, we use small-angle neutron scattering and dynamic light scattering to determine that these particles consist of a cross-linked core with long polymer tails that extend into the dispersing medium. Carboxylic acid groups present on the tails deprotonate with increasing pH, and the extension of the polymer chain due to charge repulsion increases the hydrodynamic drag on the particle. Here we find that adjusting the pH alone has a much more significant effect on the shear dependence of the viscosity of the studied resin than adding organic solvent alone. We also find that this resin architecture is more responsive per mole of pH-responsive group than other architectures of pH-responsive latex particles in the literature.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Phenolic Resin Derived Hard Carbon Anode for Sodium-Ion Batteries: A Review

Sodium-ion batteries are complementary to lithium-ion batteries for grid-scale energy storage applications due to lower cost, safety, and potential for sustainable supply chains. The past decade has witnessed enormous research efforts in developing hard carbon anode materials for sodium-ion batteries. Phenolic resins have received significant attention as hard carbon precursors due to their high carbon yield, highly cross-linked structure, low cost, mature technology, and excellent electrochemical performance of corresponding hard carbon anode. This Review exclusively highlights the state-of-the-art preparation of hard carbon from phenolic resins, and the electrochemical performance in sodium-ion batteries. Cross-linked resins are prepared from three phenolic monomers (phenol, resorcinol, and phloroglucinol) to produce hard carbon. The effects of carbonization temperature on the microstructure, and electrochemical properties of hard carbon have been summarized here. Hard carbon formation, and sodium storage mechanisms have been briefly outlined. Finally, this Review provides an industrial perspective on hard carbon production at scale.

aromatic compounds↗
DOE OSTI2024

Enhancing Resource Recovery through Electro-Assisted Regeneration of an Ammonia-Selective Cation Exchange Resin

Ammonia-selective adsorbents can manage reactive nitrogen in the environment and promote a circular nutrient economy. Weak acid cation exchangers loaded with zinc exhibit high ammonia selectivity but face two implementation barriers: the stability of the zinc–carboxylate bond in complex wastewaters and energy- and logistics-intensive adsorbent regeneration with acidic solutions. In this paper, we examined the stability of zinc–carboxylate bonds in varying solutions (pure ammonium solution, synthetic urine, and real urine) and during electro-assisted regeneration. For electrochemical regeneration, both electrolyte concentration and current density influenced the trade-off between ammonia regeneration and zinc elution. Using 10 mM K 2 SO 4 anolyte at a 0.08 mA/cm 2 current density, we achieved 4% zinc elution and 61% ammonia regeneration. In contrast, using 100 mM K 2 SO 4 at 4.96 mA/cm 2 improved the regeneration efficiency to 97% but eluted 60% of zinc. We found that electrolyte concentration was the key factor influencing the regeneration efficiency of the NH 3 -selective adsorbents. Due to prevalent zinc elution, we designed an in situ procedure for reforming the zinc–carboxylate bond and achieved similar adsorption densities between pre- and post-regenerated resins, thus enabling multiple cycle resin use. Ultimately, this study advances understanding of ammonia-selective resins that can facilitate high-purity, selective, and durable recovery of nutrients from waste streams.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

A Mechanism-Based Reaction–Diffusion Model for Accelerated Discovery of Thermoset Resins Frontally Polymerized by Olefin Metathesis

Frontal ring-opening metathesis polymerization (FROMP) involves a self-perpetuating exothermic reaction, which enables the rapid and energy-efficient manufacturing of thermoset polymers and composites. Current state-of-the-art reaction–diffusion FROMP models rely on a phenomenological description of the olefin metathesis kinetics, limiting their ability to model the governing thermo-chemical FROMP processes. Furthermore, the existing models are unable to predict the variations in FROMP kinetics with changes in the resin composition and as a result are of limited utility toward accelerated discovery of new resin formulations. In this work, we formulate a chemically meaningful model grounded in the established mechanism of ring-opening metathesis polymerization (ROMP). Our study aims to validate the hypothesis that the ROMP mechanism, applicable to monomer-initiator solutions below 100 °C, remains valid under the nonideal conditions encountered in FROMP, including ambient to >200 °C temperatures, sharp temperature gradients, and neat monomer environments. Through extensive simulations, we demonstrate that our mechanism-based model accurately predicts the FROMP behavior across various resin compositions, including polymerization front velocities and thermal characteristics (e.g., T max ). Additionally, we introduce a semi-inverse workflow that predicts FROMP behavior from a single experimental data point. Notably, the physiochemical parameters utilized in our model can be obtained through DFT calculations and minimal experiments, highlighting the model’s potential for rapid screening of new FROMP chemistries in pursuit of thermoset polymers with superior thermo-chemo-mechanical properties.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Nitrated Anion Exchange Resin Disposal Plan Calcination Studies

Reillex HPQ resin was nitrated in a manner matching procedures in use by the Aqueous Nitrate Recovery Facility. The resin was kept wet and then calcined to determine if nitrate was present in the residue. The potential for dispersion during heating and generation of soot or ash was evaluated. A series of experiments were performed by calcining the resin to 650 °C, and both residual solids and liquids were collected and measured for nitrates by Raman spectroscopy and test strip measurements.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2025

Exploring the functional performance of a commercial hightemperature photopolymer resin for vat photopolymerized injection molding tools

• Selective photopolymerization of a liquid photocurable resin using ultraviolet (UV) or visible light in discrete layers • Photocurable resins are typically a mixture of monomer(s), oligomer(s), photoinitator(s), and additive(s), when applicable • Recent advances in high-performance resins have made VPP increasingly viable for functional tooling applications

Jones, Haley W. [Savannah River National Laborator↗
NASA NTRS1967

Photosensitive filler minimizes internal stresses in epoxy resins

Photosensitive filler is added to curable epoxy resins to minimize stress from internal shrinkage during curing or polymerization. Cinnamic acid resins and cinnamal ketones may be added in the amount of 1 to 3 percent by weight of the resin mixture.

Dillon, J. N.↗
NASA NTRS1972

Moisture effects on the high-temperature strength of fiber-reinforced resin composites.

Under NAS 8-27435, the Convair Aerospace Division of General Dynamics and their subcontractor, Hercules Incorporated, have conducted studies on the effects of moisture on the properties of fiber-reinforced resin composites and on the epoxy resins presently used in advanced composites. Data are presented on the resins and composites subjected to varying time/temperature/humidity or time/temperature/water-boil exposures. The effects of moisture on matrix, reinforcement, and fiber/resin interface are discussed and supported by experimental test data.

Hertz, J.↗
NASA NTRS1976

Recent advances in the development of composites based on the NCNS resins

The NCNS resins, a new class of addition polymerized polyaromatic melamines, have undergone further development in the past year. Pilot plant quantities of resin NCNS-12M have been made available for evaluation. High solids laminating varnishes were prepared in alcohol/ethyl acetate and alcohol/chlorinated solvent mixtures. The prepregs had sufficient room temperature stability after three month storage to retain good processing characteristics and good bonded mechanical properties. Laminates were fabricated by vacuum bag-autoclave processing and by 5 minute press molding cycles. These laminates had low flame spread and low smoke emitting properties and retained good elevated temperature properties upon long-term oxidative aging. Humidity aging studies were carried out for 30 days at 95% R.H., 120 F. on NCNS/graphite fiber laminates. Initial results indicate that the NCNS resins, particularly those prepared from polymethylene polyphenylamines, are resistant to environmental degradation of elevated temperature mechanical strength.

Kray, R. J.↗
NASA NTRS1980

Improved microbial-check-valve resins

Improved microbial-check-valve resins have been tested for their microbicidal effectiveness and long-term stability. Resins give more-stable iodine concentrations than previous preparations and do not impart objectionable odor or taste to treated water. Microbial check valve is small cylindrical device, packed with iodide-saturated resin, that is installed in water line where contamination by micro-organisms is to be prevented. Prototype microbial check valve was tested for stability and performance under harsh environmental conditions. Effectiveness was 100 percent at 35 deg, 70 deg, and 160 deg F (2 deg, 21 deg, and 71 deg C).

Colombo, G. V.↗
NASA NTRS1978

Bismaleimide resins for flame resistant honeycomb sandwich panels

A 60 kg batch of Resin M751 was produced in pilot plant scale. The resin was delivered to the prepreg company as an NMP solution. 100 kg of glass-fabric prepregs were fabricated. Prepreg characteristics and curing cycles for laminate fabrication were provided. A new batch of Resin M756 (Code M756 - 2) was synthesized.

Source record↗
NASA NTRS1979

Moisture diffusion parameter characteristics for epoxy composites and neat resins

The moisture absorption characteristics of two graphite/epoxy composites and their corresponding cured neat resins were studied in high humidity and water immersion environments at elevated temperatures. Moisture absorption parameters, such as equilibrium moisture content and diffusion coefficient derived from data taken on samples exposed to high humidity and water soak environments, were compared. Composite swelling in a water immersion environment was measured. Tensile strengths of cured neat resin were measured as a function of their equilibrium moisture content after exposure to different moisture environments. The effects of intermittent moderate tensile loads on the moisture absorption parameters of composite and cured neat resin samples were determined.

Long, E. R., Jr.↗
NASA NTRS1979

Feasibility study on the development of tough, moisture-resistant laminating resins

The potential of cyanate resins as replacement for epoxy resins in composites with graphite fiber reinforcement was investigated in an effort to provide improved moisture resistance and toughness in laminating systems at a projected cost, handleability, and processing requirements equivalent to 400 K (260 F) curing epoxies. Monomer synthesis, formulation, blending, resin preparation, catalysis studies, prepreg preparation, laminate fabrication, and testing are discussed. A graphite fiber reinforced laminate was developed with 95 percent retention of the original 363 K (180 F) flexural strength and 70 percent retention of the 363 K (180 F) short beam shear strength after 500 hour exposure to 95 + 7 relative humidity at 324 K (120 F).

Brand, R. A.↗