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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 55 records · Page 3

Glycerol-based sustainably sourced resin for volumetric printing

Volumetric Additive Manufacturing (VAM) represents a revolutionary advancement in the field of Additive Manufacturing, as it allows for the creation of objects in a single, cohesive process, rather than in a layer-by-layer approach. This innovative technique offers unparalleled design freedom and significantly reduces printing times. A current limitation of VAM is the availability of suitable resins with the required photoreactive chemistry and from sustainable sources. To support the application of this technology, we have developed a sustainable resin based on polyglycerol, a bioderived (e.g., vegetable origin), colourless, and easily functionisable oligomer produced from glycerol. To transform polyglycerol-6 into an acrylate photo-printable resin we adopted a simple, one-step, and scalable synthesis route. Polyglycerol-6-acrylate fulfils all the necessary criteria for volumetric printing (transparency, photo-reactivity, viscosity) and was successfully used to print a variety of models with intricate geometries and good resolution. The waste resin was found to be reusable with minimal performance issues, improving resin utilisation and minimising waste material. Furthermore, by incorporating dopants such as poly(glycerol) adipate acrylate (PGA-A) and 10,12-pentacosadyinoic acid (PCDA), we demonstrated the ability to print objects with a diverse range of functionalities, including temperature sensing probes and a polyester excipient, highlighting the potential applications of these new resins.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Silicone Resins for Vat Polymerization Printing

This paper reviews research of silicone-based resins for vat polymerization printing (VPP). Silicone resins are used commonly in other 3D printing technologies because of their desirable properties. Silicones are chemically inert, oxidatively, and thermally stable, and have the lowest glass transition temperature of any polymer. Creating silicone resins processable by VPP is challenging because VPP requires low viscosity liquid resin that quickly photopolymerizes. This review will summarize VPP technologies, resin chemistries, and recent research of silicone VPP resins.

36 MATERIALS SCIENCE↗

Systems and methods for liner braiding and resin application

A method of making a tank for storing fluid that includes generating a resinated braid layer on an elongated liner having a plurality of successively alternating rigid and flexible portions along the length of the liner. Generating the resinated braid layer on the liner includes feeding the liner into a braiding machine and applying resin to a plurality of fibers during a braiding process to generate a resinated plurality of fibers and generating, over a length of the liner, by the braiding machine, the resinated braid layer defined by the resinated plurality of fibers.

Wexler, Jason Stein↗

Behavior of selenium and arsenic in $\mathrm{HCl}$ and $\mathrm{HNO}$ 3 on $\mathrm{TRU, TEVA, DGA,}$ and $\mathrm{Pb}$ extraction chromatography resins

The uptake behavior of 73 As and 75 Se was studied in HCl and HNO 3 -H 2 O 2 solutions on commercial extraction chromatography resins (TEVA, TRU, DGA, and Pb resin). There was no uptake of 73 As or 75 Se from HNO 3 media. From HCl, there was 75 Se uptake at high concentrations on all the resins and no uptake of 73 As. Separations of 75 Se and 73 As on these resins have high yields and high radiopurity for 73 As, but limited recovery of 75 Se. TRU and TEVA resin may have potential for use in isotope generators as 75 Se can be retained for at least 26 days with repeated elutions.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗

Regeneration of anion-exchange resins for cyclic selenium removal from industrial wastewaters

Application of ion exchange for the removal of selenium (Se) oxyanions from industrial wastewaters is often limited by ineffective regeneration of the ion-exchange resins, particularly in complex systems containing competing ions, such as coal-ash leachate containing high-sulfate concentrations and heavy metal ions. Here, in this study, it was first demonstrated that while conventional regeneration with sodium chloride (NaCl) is effective for simulated wastewater, with ∼80% efficiency, NaCl fails to regenerate resin loaded with real industrial wastewater, achieving less than 20% efficiency. To overcome this challenge, a two-step regeneration process was investigated using a sodium carbonate (Na 2 CO 3 ) solution for elution, followed by a NaCl solution for restoration. Compared to the one-step NaCl regeneration, this integrated process restored more than 80% of the resin's capacity with real industrial wastewaters. Beyond demonstrating regeneration performance, this research emphasizes fundamental mechanistic interpretations of the observed regeneration behavior across different water matrices and experimental conditions. Particularly, accounting for pH-dependent carbonate speciation, it is proposed that the elution step exploits the resin's strong affinity for divalent carbonate ions to displace strongly bound contaminants, while the subsequent restoration step relies mainly on the mass action effects of chloride ions to regenerate the resin sites. The protocol was optimized to achieve rapid regeneration (<10 min) using moderate chemical concentrations (0.5 M) in treating real leachate. In batch cyclic experiments, Se regeneration reached nearly complete recovery after five consecutive sorption and desorption cycles, while in the fixed-bed system, the regeneration efficiency remained at approximately 80% after five cycles.

Anion-exchange resin↗

Separation of zirconium and hafnium from early actinides and rare earth elements with eichrom’s pb resin in HCl

The separation of zirconium and hafnium isotopes from the early actinides and rare earth elements (REE) with Eichrom’s Pb resin has been studied. Batch studies were performed to characterize the behavior of actinium, thorium, zirconium, hafnium, lutetium, and yttrium on Pb resin from HCl solutions (0.001 M to 11 M). The early actinides and REE had no affinity for the resin at any concentration of HCl, but zirconium and hafnium showed a moderate uptake at high concentrations of HCl with a maximum extraction at 11 M HCl. Several column separations were tested, including with only tracer isotopes and with mass. Rapid, simple separations of zirconium from actinium, thorium, protactinium, and the REE with high yields and low elution volumes are presented with applications for tracer isotope production and fission product separations. Furthermore, the resin is less suitable for hafnium separations as hafnium tends to bleed off the resin even at high concentrations of HCl.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗

From acetone fractionation to lignin-based phenolic and polyurethane resins

In this paper, acetone fractionation was used to increase the homogeneity of softwood kraft lignin for product development. The acetone soluble and insoluble fractions were analyzed in terms of elemental composition, chemical structure, and thermal properties. The phenolic hydroxyl content of the acetone soluble fraction increased by 24%. The acetone soluble fraction of kraft lignin was used to fully substitute phenol in phenolic resin formulation. The resulting formulated lignin-formaldehyde adhesive showed higher adhesion strength (4.3 MPa) compared to a lab formulated phenol-formaldehyde resin (3.4 MPa) with 100% wood failure after lap shear test. On the other hand, the acetone insoluble lignin fraction, which had 23% higher aliphatic hydroxyl content compared to the starting lignin, was used to entirely replace petroleum-based polyol in polyurethane resin formulation. Then a bio-derived solvent (dihydrolevoglucosenone, Cyrene) was used to dissolve the acetone insoluble lignin fraction to synthesize lignin-based polyurethane resin. Tailoring the structure of kraft lignin through solvent fractionation resulted in two fractions, which were used to replace 100% of two major petrochemicals (phenol and polyol) in the formulations of phenolic and PU resins, that would otherwise be challenging due to the heterogeneity of softwood kraft lignin.

36 MATERIALS SCIENCE↗

Atomic scale understanding of organic anion separations using ion-exchange resins

A combination of ab initio and classical molecular dynamic simulations was used to explore the adsorption/desorption and diffusion characteristics of ion-exchange resins for extraction of organic anions in electrically-driven separation processes. We considered two classes of carboxylate mixtures that are commonly encountered in bioprocessing separations: a short chain fatty acid mixture (acetate/butyrate) and an aromatic mixture (ferulate/coumarate). The suitability of several resin materials including PFC100E, IRC86, PFA444 and IRA67 was interrogated. The decomposition of the interaction energies by the symmetry-adapted perturbation theory and the classical molecular dynamic simulations of organic diffusion together reveal that the geometries of the organic anions and the functional groups of the resins, as well as their Columbic interactions, are the controlling factors in the diffusion process of the organic compounds in these resins. Additionally, classical simulations also show that modifying the functionality of resin beads, the magnitude of electric fields, and the ratio of organic mixtures may provide an effective way to control the diffusion rate and obtain selective separation of these organic mixtures. Finally, a general suggestion for favorable separation conditions is summarized.

36 MATERIALS SCIENCE↗

Exploring New Resin Systems for Nb3Sn Accelerator Magnets

Epoxy resins have long been a focus of magnet design. They provide strength and stability to the superconductor, to allow coil fabrication and consistent magnet performance. They are often cited as a main contributor to magnet performance, often as a limiting factor, from epoxy cracking and energy release. New resin systems are being designed to improve magnet quench and training performance through several means. Baseline candidate resin systems are evaluated for neat resin mechanical properties as well as behavior in Nb 3 Sn subscale composites. Furthermore, this data feeds additional resin system tuning to meet the goals stated above.

43 PARTICLE ACCELERATORS↗

Two–Photon Printing of Base–Catalyzed Resins Involving Thiol–Michael Network Formation

Two-photon printing is accomplished using a photobase generator, 2-(2-nitrophenyl)-propyloxycarbony tetramethyl guanidine, to locally catalyze thiol-ene coupling between multifunctional monomers while mitigating chain-growth polymerization with free radical scavengers. Microstructures printed from base-catalyzed resins exhibit higher resolution (linewidths < 400 nm) and lower print error (<3%) than analogous microstructures printed using a photosensitive, free radical initiator. Further, Raman spectroscopy reveals that resins polymerized using the photobase generator in the presence of free radical scavengers exhibit higher selectivity of thiol-ene coupling over radical polymerization, resulting in stiffer, more uniform polymer networks. The base-catalyzed resins are capable of producing 3D microstructures printed with high accuracy and minimal post-processing defects. As a result, a direct comparison between free radical and base-initiated resins highlights the need for mindful consideration of how chemical reaction pathway influences printability and network end-properties when designing resins.

36 MATERIALS SCIENCE↗

Solventless Dual‐Cure Liquid Resins Via Circular Use of Phthalic Anhydride for Recyclable Composite Applications

Abstract Fiber‐reinforced composites (FRCs) possess a remarkable strength‐to‐weight ratio, making them ideal light‐weighing alternative materials of metals used in automotive, aerospace, and outdoor equipment applications, but their recycling is challenging. Chemically recyclable thermoset polymers can enable fiber recovery and reuse; however, challenges remain in the separation and purification of depolymerized small molecules for efficient polymer recycling. To this end, a series of liquid resins for chemically recyclable polymer networks is designed based on phthalic anhydride, a widely produced and inexpensive chemical. The straightforward sublimation of phthalic anhydride is leveraged to enable a simple and efficient separation process for polymer recycling. To liquefy phthalic anhydride, five mono‐acryloyl‐phthalates are synthesized to obtain stable liquid resins together with phthalic diglycidyl ester. These liquid resins undergo dual‐cure reactions that comprise photopolymerization of acrylate and, subsequently, heat‐mediated epoxy‐acid polymerization reactions. These liquid resins exhibit moderate viscosities (2600–6400 cP @ 22 °C), fast curing, and robust thermomechanical properties (T g s from 71 to 116 °C). It is demonstrated that hydrolysis of the dual‐cured polymers completes within 2 h at 80 °C, and direct sublimation produces phthalic anhydride with 82% yield. This resin system is expected to provide a cost‐competitive, highly efficient platform for recyclable FRCs.

Polymer Science↗

Part I: Predicting performance of Purolite A532E resins for remediation of comingled contaminants in groundwater

Ion exchange (IX) resins are used in pump-and-treat (P&T) facilities to remove soluble groundwater contaminants. However, natural anions present at concentrations orders of magnitude higher than contaminants can compete for IX sites and impact resin lifecycles. Here, the Hanford Site’s 200 West Area P&T facility (Washington State, USA) was selected as a case study because it currently uses two IX resins: Purolite® A532E (A532E) to remove pertechnetate (TcO 4 - ) and DOWEX 21K (DOWEX) to remove uranium from groundwater. Nitrate (NO 3 - ), sulfate (SO 4 2- ), chloride (Cl - ), and carbonate (CO 3 2- ) anions have been identified to potentially compete for A532E and DOWEX IX sites. Hanford-relevant anion groundwater concentrations were used to design a series of laboratory-scale batch experiments to evaluate the impact of competing anions on resin performance and potential kinetic effects. These data are then modeled to obtain Cl--normalized equilibrium exchange coefficients (K) needed to predict IX resin performance. The work is presented in two parts, with IX performance evaluated for A532E in Part I and DOWEX in Part II. Part I results demonstrate that TcO 4 - uptake is not impacted by NO 3 - , SO 4 2- , Cl - , CO 3 2- (as HCO 3 - ) and U(VI) carbonate anions, with K TcO4-/Cl- > 4,000, likely due to the high selectivity of A532E trihexylammonium sites for the large, weakly hydrated TcO 4 - anion. Other anion K values were K NO3-/Cl- = 20, K SO4--/Cl- = 0.2, K HCO3-/Cl- = 0.09, K U/Cl- = 370–1000. These K values provide conservative parameters for predicting A532E performance, and demonstrate that, under these test conditions, A532E will remove TcO 4 - from current and future influent streams to meet groundwater treatment objectives.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Rapid curing dynamics of PEG-thiol-ene resins allow facile 3D bioprinting and in-air cell-laden microgel fabrication

Thiol-norbornene photoclick hydrogels are highly efficient in tissue engineering applications due to their fast gelation, cytocompatibility, and tunability. In this work, we utilized the advantageous features of polyethylene glycol (PEG)-thiol-ene resins to enable fabrication of complex and heterogeneous tissue scaffolds using 3D bioprinting and in-air drop encapsulation techniques. We demonstrated that photoclickable PEG-thiol-ene resins could be tuned by varying the ratio of PEG-dithiol to PEG norbornene to generate a wide range of mechanical stiffness (0.5–12 kPa) and swelling ratios. Importantly, all formulations maintained a constant, rapid gelation time (<0.5 s). We used this resin in biological projection microstereolithography (BioPµSL) to print complex structures with geometric fidelity and demonstrated biocompatibility by printing cell-laden microgrids. Moreover, the rapid gelling kinetics of this resin permitted high-throughput fabrication of tunable, cell-laden microgels in air using a biological in-air drop encapsulation apparatus (BioIDEA). We demonstrated that these microgels could support cell viability and be assembled into a gradient structure. This PEG-thiol-ene resin, along with BioPµSL and BioIDEA technology, will allow rapid fabrication of complex and heterogeneous tissues that mimic native tissues with cellular and mechanical gradients. The engineered tissue scaffolds with a controlled microscale porosity could be utilized in applications including gradient tissue engineering, biosensing, and in vitro tissue models.

36 MATERIALS SCIENCE↗

Reilly Industries Resin Purchased by LLNL

The Chemical Operations Group has a stock of Reillex HPQ resin that was purchased from Reilly Industries in 1998. This report was written to give context to the currently available options for obtaining polyvinylpyridine based resin such as Reillex HPQ. The resin is no longer manufactured, and the only available options are holdings from Reilly Industries such as that at LLNL or a production run of Reillex HPQ by Vertellus in 2015. This Verellus production run was commissioned and purchased by Savannah River Site. This report and references establish LLNL’s current stock as a polyvinylpyridine based resin. Additionally, this report and references establish that the formulation of Reillex HPQ is only 70% polyvinylpyridine by design. The 30% divinylbenzene does not constitute an impurity but an integral crosslinking component of the resin itself.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗

Resin transfer molding systems and control logic for manufacturing fiber-reinforced composite parts

Presented are manufacturing control systems for fabricating composite-material structures, methods for making/operating such systems, and resin transfer molding techniques for ameliorating race-tracking effects in fiber-reinforced polymer panels. A method for forming a composite-material construction includes confirming, via a system electronic control unit (ECU), that a fiber-based preform is placed in a mold cavity and that opposing mold segments of the molding apparatus are sealed together. A filler, such as a compressible bladder, a cluster of spring-biased pins, or a spray-chopped fiber bed, is introduced into a void between the fiber-based preform and a tool face of one mold segment to thereby eliminate an unwanted resin race track. The system ECU commands a resin pump to inject resin through a primary gate of the molding apparatus and into the mold cavity to thereby impregnate the fiber-based preform with the resin. One or more vents operate to evacuate air from the mold.

Rodgers, William R.↗

Evaluation of two extraction chromatography resins for scandium and titanium separation for medical isotope production

Scandium-47 ( 47 Sc) can be used in nuclear medicine as a therapeutic-diagnostic, or "theragnostic," radioactive medical isotope for cancer detection and treatment. The 47 Sc isotope can be produced through the photonuclear reaction 48 Ti(γ,p) 47 Sc by irradiating enriched 48 Ti target material. The enriched target material necessary for production is costly; 48 TiO 2 costs ~ $\$$1550/g, and targets can be > 50 g ($\$$77,500) to produce medically relevant amounts of 47 Sc. In order to keep costs low, a highly efficient separation of scandium from bulk titanium is desired, along with efficient methods for recycling the target material. Here this research is focused on evaluating efficient methods for the separation of scandium from bulk quantities of titanium using commercially available diglycolamide-based and hydroxamate-based extraction chromatography resins (DGA resin and ZR resin, respectively). The sorption of 47 Sc and Ti on these resins were investigated at varying concentrations of HNO 3 , HCl, H 2 SO 4 , and HF to explore how they might be used in a large-scale production/processing setting.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗

Extraction of gold, mercury and lead on CL resin in HCl

The uptake behavior of 197 mHg, 194 Au and 212 Pb in HCl on CL resin (Triskem) was studied. The extraction of mercury and gold is high (D w > 5,000) at all concentrations of HCl, with a maximum extraction of gold at 4 M HCl (D w ~ 53,000) and maximum extraction of mercury at 0.01 M HCl (D w ~ 44,000). Lead has moderate uptake on CL resin (D w ~ 100) from lower concentrations of HCl (0.001 to 0.05 M) and no uptake on the resin in concentrations ≥ 0.4 M. The uptake kinetics are similar for all three isotopes with high weight distribution ratios (>1,000 for 197 mHg, 194 Au and > 100 for 212 Pb) in ~ 30 s and equilibrium established at ~ 5 min. A column study was performed to demonstrate that 197m Hg, 194 Au and 212 Pb could be retained on CL resin in dilute HCl and 212 Pb eluted in 1 M HCl with no detectable 197m Hg or 194 Au. Elution of 197 mHg and 194 Au was performed with concentrated HNO 3 , but with significant losses to the column, particularly for 194 Au.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗

Extraction of gold, mercury, and lead with TEVA resin from HCl and HNO 3

The extraction behavior of 212 Pb, 197m Hg, and 194 Au on TEVA resin in HCl and HNO 3 solutions was studied with batch uptake, kinetics, and column studies. The uptake of mercury and gold was extremely high from HCl solutions, with maximum k’ >80,000 for both elements. The uptake of mercury was lower in HNO3 than HCl with a maximum k’ of ~ 8,000 in 0.02 M HNO 3 and decreasing uptake at higher concentrations of HNO3, which agrees well with previous work. The batch uptake of gold in HNO 3 was not measured, as it had been reported previously. The uptake of lead on TEVA resin in HCl was low with a maximum k’ of only ~ 90 in 1 M HCl. The uptake of lead in HNO 3 was negligible. The uptake kinetics of gold and mercury were characterized in HCl and HNO 3 solutions and high uptake was seen after ~ 60 s for both elements. Column separations of 212 Pb, 197m Hg, and 194 Au on TEVA resin from HCl and HNO 3 solutions are reported with high yields of mercury and lead, but with high losses of gold, which is retained on the resin. A rapid, high yield separation of 197m Hg from irradiated gold foils is presented with yields of ~ 100% for both elements and a total separation time of < 2 h.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗