Search NASA⌕ Search

SEARCH · Search NASA

Results for “PLA”

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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Application of the core shell model for strengthening polymer filament interfaces

While surface segregation has been intensively studied in thin films, relatively little has been investigated in filament geometries. In contrast to thin films, the filament surface forms a continuum, with interactions both at the free air and internal filament interface, which makes it difficult to achieve an equilibrium configuration. This asymmetry has become particularly apparent with the increasing use of additive manufacturing where entire structures are constructed via layered deposition of filamentous layers from a moving thermal nozzle. In addition, this process is highly non-equilibrated with poor thermal retention and is responsible for insufficient filament–filament interfacial fusion and internal pore formation along the printing direction. These features all contribute to poor mechanical and structural properties, which are exacerbated in semi-crystalline polymers, such as Polylactic Acid (PLA), where the melting point, T m , is much higher than the glass transition, T g . Even though system is liquid the molecules become ordered within the crystal structure and this ordering interferes with interdiffusion, which in turn prevents proper interfacial fusion. Capitalizing on the differential in surface tension, we show that addition of less than 1%, or trace amounts, of longer chain polymers, an oriented core shell structure, will be formed with a self-limiting thickness of three time the radius of gyration, R g , of the tracer chains. The lower T g of the tracers and their orientation makes them poised for interdiffusion when subsequent layers are deposited producing structures with significant improvement of the mechanical properties and internal structural integrity.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Creep suppression and fatigue in bio-based composites manufactured via conventional and large format additive manufacturing processes

The emergence of novel extrusion-based additive manufacturing (AM) processes has prompted the development of new thermoplastic composite feedstocks, and broadening sustainability initiatives have driven the development of bio-based and recyclable material for AM feedstocks. Poly(lactic acid) (PLA) with wood flour (WF) is one composite system that has been demonstrated in numerous AM applications, as well as traditional processing methods (i.e., compression and injection molding); however, there has been a need to understand how the variation in processing methodology impacts the material performance of these bio-based feedstocks from a fundamental perspective, with particular emphasis on creep for an extended application use-life. Herein, PLA/WF is explored as a feedstock material for large format additive manufacturing (LFAM) and the performance of additively manufactured materials is compared to those produced via more traditional processing methods. It is also demonstrated that the addition of WF decreases the material’s coefficient of thermal expansion (CTE) while increasing its Young’s modulus, susceptibility to water uptake, and creep fatigue resistance. Essentially, the addition of 20 wt% WF results in a 92 % decrease in rubbery regime CTE while simultaneously resulting in a 14 % increase in modulus, 190 % increase in water uptake, and a 31 % decrease in residual strain after cyclic creep tests. The processing method was also found to play a large role in the final part performance, with the printed material increasing the crystallinity by 183 % and 214 % compared to its compression and injection molded counterparts. Furthermore, the porosity of printed samples increased by two orders of magnitude compared to samples prepared via traditional processing methods.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Mixed polyester recycling can enable a circular plastic economy with environmental benefits

The mixed and varied nature of fossil-based and bio-based plastic waste requires complex and costly separations to enable compatibility with recycling technologies. A circular plastic economy based on mixed polyesters through cleaving ester bonds to produce monomers, while re-utilizing bio-based monomers to produce high-quality sustainable plastics, charts an exciting solution. However, the feasibility of such a circular economy solution remains underexplored. Here, in this study, we conducted a techno-economic analysis and life-cycle assessment of three polyester depolymerization recycling processes-methanolysis, glycolysis, and acid hydrolysis-for a mixed feedstock (polyethylene terephthalate [PET], polylactic acid [PLA], and polybutylene adipate terephthalate [PBAT]). Methanolysis outperforms glycolysis and hydrolysis economically and environmentally due to more efficient downstream separations, generating products with a 31% decrease in selling price and 21%-46% reduction in acidification, carcinogenic toxicity, fossil-fuel depletion, global warming potential, particulate formation, and smog formation compared to conventional polyester manufacturing. This study highlights the viability of a circular plastic economy for mixed polyesters via a single chemical recycling process.

09 BIOMASS FUELS↗
DOE OSTI2024

Formation of Disordered Cocontinuous Phases by Randomly Linked Star Copolymers

Cocontinuous polymeric nanostructures have garnered significant interest due to their ability to combine different properties of two separate polymer domains. Randomly linked copolymer networks have proven to be especially robust for formation of disordered cocontinuous phases across wide composition ranges (≈30 wt % or more). While theoretical treatments of microphase-separated networks have focused primarily on the role of random elastic forces imposed on the self-assembled nanostructures by virtue of the network architecture, experimental studies seeking to disentangle these contributions from other potential effects, such as dispersity in preferred interfacial curvatures, have been scarce. To provide insight into this matter, we here study the self-assembly of randomly linked star copolymers (RSCs), constructed by linking premade polymer arms of polystyrene (PS) and poly(d,l-lactide) (PLA) using 3, 4, and 6-functional connectors. This architecture yields similar distributions of preferred curvature as networks made using corresponding difunctional strands, but lacks the elastic forces imposed by a network architecture. Gravimetry and small-angle X-ray scattering, coupled with scanning electron microscopy, were performed to identify the percolation of PS/PLA RSCs. Remarkably, the 4-arm RSC system exhibited a disordered cocontinuous window of ≈25 wt %, indicating that dispersity in preferred curvature can in some cases be sufficient to robustly drive formation of this morphology. However, the other RSC architectures showed smaller cocontinuous ranges, which we interpret in terms of the influence of homopolymer stars in the 3-arm case and the narrower distribution of preferred interfacial curvatures in the 6-arm case. Finally, thin layers of interconnected porous PS were achieved by solution-processing, suggesting that RSCs have the potential to serve as a robust and easily processable cocontinuous polymeric nanomaterials in both bulk and membrane geometries.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

Microphase Separation of Randomly Linked Branched Polystyrene/Polylactic Acid for Formation of Cocontinuous Nanostructures

Cocontinuous polymeric nanomaterials have gained attention for their ability to preserve distinct properties of constituent microphases within a single material. Randomly linked copolymer networks have shown very wide stability windows for disordered cocontinuous phases (extending over ≈ 30 wt % in composition), but the reliance on a network architecture prevents subsequent solution- or melt-processing. Furthermore, the key factors contributing to cocontinuity have remained unclear. We recently found that randomly linked star copolymers (RSCs) can exhibit a cocontinuous window as wide as 25 wt % in the case of 4-arm stars, suggesting that while a network architecture is not essential for the formation of disordered cocontinuous phases, the presence of random elastic forces in such architectures may indeed facilitate their formation. In addition, the behavior was found to be highly sensitive to arm number, with 6-arm RSCs exhibiting almost no cocontinuous phase. These results raised a key mechanistic question regarding the contribution of random elastic forces, originating from strands that bridge between junctions, in stabilizing disordered cocontinuous phases. In the current study, we synthesized randomly linked branched copolymers (RBCs) of polystyrene (PS) and poly(D,L-lactic acid) (PLA), which represent an intermediate architecture between networks and stars. This approach allows for the introduction of elastic contributions from strands bridging between different junctions, while still maintaining the processability advantages of a non-network architecture. The cocontinuous regions of the PS/PLA RBCs, with varying polymer and linker functionalities (f p and f l , respectively), were characterized by small-angle X-ray scattering, gravimetry, and scanning electron microscopy. We found that the cocontinuous windows of RBCs typically expanded with increasing elastic contributions and exhibited reduced sensitivity to junction-functionality compared to RSCs. Notably, RBCs with f p = 1.50 and f l = 3, which had large molecular weights due to proximity to the gel point, achieved a cocontinuous window of ≈ 34 wt %, which is almost twice as wide as analogous 3-arm RSCs and comparable to randomly linked networks. Leveraging this robust cocontinuity and solution-processability, we fabricated a film of interconnected nanoporous PS.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Poly(lactic acid)-Based Ink for Biodegradable Printed Electronics With Conductivity Enhanced through Solvent Aging

Biodegradable electronics is a rapidly growing field, and the development of controllably biodegradable, high-conductivity materials suitable for additive manufacturing under ambient conditions remains a challenge. Here, printable conductive pastes that employ poly(lactic acid) (PLA) as a binder and tungsten as a conductor are demonstrated. These composite conductors can provide enhanced stability in applications where moisture may be present, such as environmental monitoring or agriculture. Post-processing the printed traces using a solvent-aging technique increases their conductivity by up to 2 orders of magnitude, with final conductivities approaching 5000 S/m. Such techniques could prove useful when thermal processes including heating or laser sintering are limited by the temperature constraints of typical biodegradable substrates. Finally, both accelerated oxidative and hydrolytic degradation of the printed composite conductors are examined, and a fully biodegradable capacitive soil moisture sensor is fabricated and tested.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Assembly of Disordered Cocontinuous Morphologies by Multiblock Copolymers with Random Block Sequence and Length Dispersity

Among the wide variety of nanostructures accessible by self-assembly of block copolymers, cocontinuous morphologies are of great interest for separations, catalysis, sensing, and energy storage due to their ability to integrate distinct properties of the constituent polymers. Furthermore, we investigate the tendency to form disordered cocontinuous phases of multiblock copolymers (MBCs) with random block sequence and length dispersity prepared by step-growth polymerization of pre-made telechelic polymers, specifically using thiol-Michael addition between diacrylate functionalized polystyrene (PS) and poly (D,L - lactide) (PLA) chains and a small molecule dithiol. In the phase diagram so established, disordered cocontinuous nanostructures occupy a wide window (≈ 25 % vol) at a modest segregation strength of χN = 15, close to the critical value for microphase separation. At a higher segregation strength of χN = 30, only a moderately wide (≈ 10 vol %) cocontinuous window is found, with MBCs instead tending to form ordered nanostructures. Although the breadth of the cocontinuous widow is less than that found in prior work on analogous randomly end-linked copolymer networks (RECNs), the MBC architecture offers offsetting advantages in terms of solution and melt processability.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Regio- and Stereoselective Lactone Polymerization: Divergent Effect of Catalyst Modification and Monomer Structure

Selective ring-opening polymerization (ROP) of chiral lactones enables access to biodegradable polyesters with precisely controlled microstructures. Here, combined DFT modeling and experimental validation elucidate how fine-tuning of enantiopure SalBinam aluminum catalysts (through introduction of bromine atoms and tert-butyl groups, respectively, in ortho- and para-positions) modulates regio- and stereocontrol in the ROP of methyl glycolide (MeG) and lactide (LA). Computations reveal that regioselectivity in MeG polymerization arises mainly from steric repulsion, with a small contribution from weak stabilizing C-H···Br interactions that favor ring-opening at the glycolic site, consistent with the experimentally enhanced regioselectivity for (R)-MeG. In contrast, the same steric congestion at the ligand’s ortho positions destabilizes the key transition states in rac-LA polymerization, reducing the calculated stereoselectivity. Experiments confirm the predicted loss of stereocontrol, yielding nearly atactic PLA under standard conditions. Extension of the computational framework to rac-MeG polymerization promoted by racemic catalyst identified a low-barrier, stepwise polymer chain exchange pathway that rationalizes the experimentally observed syndiotacticity of poly(lactic-co-glycolic acid).

DFT calculations↗
DOE OSTI2023

Depolymerization of polyesters by a binuclear catalyst for plastic recycling

Plastics play an essential role in modern society, however, the relentless growth of their production is threatening both human health and ecosystems. As a result, there are intensive efforts in developing recycling technologies to repurpose waste plastics into the building blocks for valuable materials. Here we show a binuclear complex that can catalyze the degradation of polyethylene terephthalate (PET)-the most widely used polyester globally-and a wide spectrum of other plastics including polylactic acid (PLA), polybutylene adipate terephthalate (PBAT), polycaprolactone (PCL), polyurethane (PU) and Nylon 66. Inspired by hydrolases, the group of enzymes that catalyze bond cleavages with water, the present catalyst design features biomimetic Zn-Zn sites which activate the plastic, stabilize the key intermediate, and enable intramolecular hydrolysis. This synthetic catalyst delivers activities of 36 mg PET d -1 g catal -1 toward PET depolymerization at pH 8 and 40 oC, and of 577 g PET d -1 g catal -1 at pH 13 and 90 oC for scalable PET recycling. We further demonstrate the closed-loop production of a bottle-grade PET. This work presents a practical and viable solution to the sustainable management of plastics waste.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

Structure-guided functional studies of plasmid-encoded dihydrofolate reductases reveal a common mechanism of trimethoprim resistance in Gram-negative pathogens

Two plasmid-encoded dihydrofolate reductase (DHFR) isoforms, DfrA1 and DfrA5, that give rise to high levels of resistance in Gram-negative bacteria were structurally and biochemically characterized to reveal the mechanism of TMP resistance and to support phylogenic groupings for drug development against antibiotic resistant pathogens. Preliminary screening of novel antifolates revealed related chemotypes that showed high levels of inhibitory potency against Escherichia coli chromosomal DHFR (EcDHFR), DfrA1, and DfrA5. Kinetics and biophysical analysis, coupled with crystal structures of trimethoprim bound to EcDHFR, DfrA1 and DfrA5, and two propargyl-linked antifolates (PLA) complexed with EcDHFR, DfrA1 and DfrA5, were determined to define structural features of the substrate binding pocket and guide synthesis of pan-DHFR inhibitors.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2025

Sustainable upcycling of polyethylene waste to compatibilizers and valuable chemicals

Controllable functionalization of polyethylene (PE) waste could generate new polymeric materials that are generally difficult to manufacture sustainably while also addressing the growing plastics waste problem. However, these modifications remain challenging due to the inherent stability of the PE backbone. Non-thermal atmospheric plasma enables molecular activation under mild conditions while utilizing renewable energy but is primarily employed for surface modification, as plasmas do not penetrate the bulk of materials. Herein, controllable bulk oxidative functionalization of PE wax (PEW) and low-density PE (LDPE) of varying molecular weights was achieved, with up to 6 mol% oxygen incorporation, by manipulating melt viscosity. This functionalization was accomplished either through temperature adjustment or by introducing a melt viscosity modifier, removable via simple extraction methods, to reduce LDPE viscosity, enhance diffusion and chain mobility, and enable bulk oxidation. The oxidized LDPE induces compatibilization in blends of poly(lactic acid) (PLA) and LDPE with improved interfacial adhesion and mechanical properties, such as a 70% increase in elongation-at-break values vs. the control. These findings pave the way for catalyst-free upcycling of direct plastics waste and plastics waste-derived products, enabling the creation of high-value products across various markets.

Plastic upcycling↗
DOE OSTI2022

Experimental Verification of Pulse Shaping in Elastic Metamaterials Under Impact Excitation

Here, we present experimental verification of pulse shaping in elastic metamaterials together with a procedure to design, fabricate, and verify metamaterial pulse shapers under impact excitation. The split Hopkinson pressure bar (SHPB) test, a fundamental dynamic test introduced more than 70 years ago, often incorporates pulse shaping as a means to alter a stress wave, providing the primary motivation for the presented study. Elastic metamaterials hold promise for enhancing conventional pulse shaping abilities and improving capabilities of the SHPB test. We first design the pulse shaper by numerically optimizing its response using finite element analysis. The pulse shaper consists of repeated unit cells based on a combination of a phononic crystal and a local resonator. Then, we fabricate and test pulse shaper candidates to validate the procedural efficacy. An iterative element corrects inaccuracies in input force and material properties and allows convergence on an appropriate pulse shaper. We carry out this procedure by designing pulse shapers fabricated from 3D-printed polylactic acid (PLA) to achieve an extended dwell acceleration pulse shape. In experimental impact tests, the procedure results in rise, dwell, and fall behaviors comparable to that predicted, effectively confirming the efficacy of the presented procedure and verifying the performance of metamaterial-based pulse shapers.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Thermal images collected during large-scale 3D printing with Ingersoll MasterPrint

This data set contains images produced to test the performance of anomaly and fault detection methods in the context of additive manufacturing. Two print jobs were executed using the Ingersoll MasterPrint with the Model 30 Strangpresse extruder. The material used was Techmer compounded polylactic acid (PLA) with wood flour as a filler (80/20 PLA/WF by weight). The first print job consists of the 3D printing of a hexagonal cylinder with a two-bead wall. This print was sliced at a gantry velocity of 3000 millimeter per minute, and an extruder screw speed of 68.14 rotations per minute. This are considered the normal operating conditions. A second hexagonal cylinder was printed using a reduced extruder screw speed, 15% lower than under normal operating conditions. The images were collected with a Teledyne FLIR Lepton 3.5 infra-red camera, a small form factor radiometric long-wave infrared camera with a spectral range of 8 µm to 14 µm. Sensor resolution was 160x120 pixels, with a pixel size of 12 µm, a temperature range of -10 - 450°C, and an accuracy of +/- 10°C in its low gain configuration. Images in this data set were collected with cameras oriented at the printer nozzle. The nozzle camera setup consisted of two cameras located 12.5cm from the nozzle center. These were mounted directly to the print head, so that the camera positions relative to the print direction would remain constant as it rotated around its C-axis to follow the print path. One camera was placed ahead of the nozzle to capture the previous layer immediately before being covered by the new layer of material, while the second camera was placed behind the nozzle and captured the freshly extruded bead. Images are collecting during each phase of the print: (a) idle (i.e., no material deposited), (b) extrusion (i.e., to prime the extruder), and (c) printing (deposition of material to manufacture the hexagonal cylinder).

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Li6Co3P8O29 by Materials Project

Li6Co3P8O29 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are twelve inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share corners with two LiO4 tetrahedra, corners with four PO4 tetrahedra, and an edgeedge with one CoO6 octahedra. There are a spread of Li–O bond distances ranging from 2.00–2.17 Å. In the second Li1+ site, Li1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Li–O bond distances ranging from 1.92–2.19 Å. In the third Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share a cornercorner with one LiO4 tetrahedra, corners with four PO4 tetrahedra, an edgeedge with one LiO6 octahedra, and an edgeedge with one CoO6 octahedra. There are a spread of Li–O bond distances ranging from 1.94–2.07 Å. In the fourth Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share a cornercorner with one LiO4 tetrahedra, corners with four PO4 tetrahedra, an edgeedge with one LiO6 octahedra, and an edgeedge with one CoO6 octahedra. There are a spread of Li–O bond distances ranging from 1.97–2.03 Å. In the fifth Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share corners with two LiO4 tetrahedra, corners with four PO4 tetrahedra, and an edgeedge with one CoO6 octahedra. There are a spread of Li–O bond distances ranging from 1.98–2.09 Å. In the sixth Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share a cornercorner with one LiO4 tetrahedra, corners with four PO4 tetrahedra, and an edgeedge with one CoO6 octahedra. There are a spread of Li–O bond distances ranging from 1.90–2.22 Å. In the seventh Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share corners with four PO4 tetrahedra, an edgeedge with one LiO6 octahedra, and an edgeedge with one CoO6 octahedra. There are a spread of Li–O bond distances ranging from 1.98–2.05 Å. In the eighth Li1+ site, Li1+ is bonded to six O2- atoms to form distorted LiO6 octahedra that share corners with six PO4 tetrahedra and edges with three LiO4 tetrahedra. There are a spread of Li–O bond distances ranging from 2.28–2.54 Å. In the ninth Li1+ site, Li1+ is bonded to four O2- atoms to form LiO4 tetrahedra that share corners with three CoO6 octahedra and corners with four PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 65–67°. There are a spread of Li–O bond distances ranging from 1.93–2.13 Å. In the tenth Li1+ site, Li1+ is bonded to four O2- atoms to form LiO4 tetrahedra that share corners with three CoO6 octahedra and corners with four PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 66–72°. There are a spread of Li–O bond distances ranging from 1.91–2.20 Å. In the eleventh Li1+ site, Li1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Li–O bond distances ranging from 1.94–2.09 Å. In the twelfth Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share a cornercorner with one LiO4 tetrahedra, corners with four PO4 tetrahedra, and an edgeedge with one CoO6 octahedra. There are a spread of Li–O bond distances ranging from 1.96–2.15 Å. There are six inequivalent Co4+ sites. In the first Co4+ site, Co4+ is bonded to six O2- atoms to form CoO6 octahedra that share a cornercorner with one LiO4 tetrahedra, corners with six PO4 tetrahedra, and an edgeedge with one LiO4 tetrahedra. There are a spread of Co–O bond distances ranging from 1.90–2.10 Å. In the second Co4+ site, Co4+ is bonded to six O2- atoms to form CoO6 octahedra that share a cornercorner with one LiO4 tetrahedra, corners with six PO4 tetrahedra, and edges with two LiO4 tetrahedra. There are a spread of Co–O bond distances ranging from 1.93–2.05 Å. In the third Co4+ site, Co4+ is bonded to six O2- atoms to form CoO6 octahedra that share a cornercorner with one LiO4 tetrahedra and corners with six PO4 tetrahedra. There are a spread of Co–O bond distances ranging from 1.91–2.10 Å. In the fourth Co4+ site, Co4+ is bonded to six O2- atoms to form CoO6 octahedra that share a cornercorner with one LiO4 tetrahedra, corners with six PO4 tetrahedra, and an edgeedge with one LiO4 tetrahedra. There are a spread of Co–O bond distances ranging from 1.84–1.99 Å. In the fifth Co4+ site, Co4+ is bonded to six O2- atoms to form CoO6 octahedra that share a cornercorner with one LiO4 tetrahedra, corners with six PO4 tetrahedra, and an edgeedge with one LiO4 tetrahedra. There are a spread of Co–O bond distances ranging from 1.87–2.16 Å. In the sixth Co4+ site, Co4+ is bonded to six O2- atoms to form CoO6 octahedra that share a cornercorner with one LiO4 tetrahedra, corners with six PO4 tetrahedra, and edges with two LiO4 tetrahedra. There are a spread of Co–O bond distances ranging from 1.90–2.06 Å. There are sixteen inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three CoO6 octahedra and corners with three LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 30–40°. There are a spread of P–O bond distances ranging from 1.54–1.59 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three CoO6 octahedra and corners with two LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 37–39°. There are a spread of P–O bond distances ranging from 1.54–1.56 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three CoO6 octahedra and corners with three LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 38–41°. There are a spread of P–O bond distances ranging from 1.53–1.57 Å. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one LiO6 octahedra, corners with two CoO6 octahedra, a cornercorner with one PO4 tetrahedra, and corners with two LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 47–48°. There are a spread of P–O bond distances ranging from 1.52–1.60 Å. In the fifth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one LiO6 octahedra, corners with two CoO6 octahedra, a cornercorner with one PO4 tetrahedra, and corners with two LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 38–52°. There are a spread of P–O bond distances ranging from 1.51–1.62 Å. In the sixth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two CoO6 octahedra, a cornercorner with one LiO4 tetrahedra, and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 39–46°. There are a spread of P–O bond distances ranging from 1.52–1.59 Å. In the seventh P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one LiO6 octahedra, corners with two CoO6 octahedra, a cornercorner with one PO4 tetrahedra, and corners with three LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 44–56°. There are a spread of P–O bond distances ranging from 1.52–1.61 Å. In the eighth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three CoO6 octahedra and a cornercorner with one LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 37–42°. There are a spread of P–O bond distances ranging from 1.53–1.57 Å. In the ninth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one LiO6 octahedra, corners with two CoO6 octahedra, a cornercorner with one LiO4 tetrahedra, and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 39–53°. There are a spread of P–O bond distances ranging from 1.52–1.62 Å. In the tenth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two CoO6 octahedra, a cornercorner with one PO4 tetrahedra, and corners with two LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 42–44°. There are a spread of P–O bond distances ranging from 1.51–1.62 Å. In the eleventh P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two CoO6 octahedra, a cornercorner with one PO4 tetrahedra, and corners with two LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 49–52°. There are a spread of P–O bond distances ranging from 1.51–1.62 Å. In the twelfth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one LiO6 octahedra, corners with two CoO6 octahedra, a cornercorner with one PO4 tetrahedra, and corners with two LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 45–48°. There are a spread of P–O bond distances ranging from 1.51–1.63 Å. In the thirteenth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one LiO6 octahedra, corners with two CoO6 octahedra, a cornercorner with one PO4 tetrahedra, and corners with two LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 39–47°. There are a spread of P–O bond distances ranging from 1.51–1.63 Å. In the fourteenth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two CoO6 octahedra, a cornercorner with one PO4 tetrahedra, and corners with three LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 47–50°. There are a spread of P–O bond distances ranging from 1.51–1.62 Å. In the fifteenth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two CoO6 octahedra, a cornercorner with one PO4 tetrahedra, and corners with three LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 39–48°. There are a spread of P–O bond distances ranging from 1.51–1.63 Å. In the sixteenth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two CoO6 octahedra, a cornercorner with one PO4 tetrahedra, and corners with four LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 47–49°. There are a spread of P–O bond distances ranging from 1.51–1.61 Å. There are fifty-eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one Co4+, and one P5+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two P5+ atoms. In the third O2- site, O2- is bonded in a trigonal planar geometry to two Li1+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two P5+ atoms. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one Co4+, and one P5+ atom. In the sixth O2- site, O2- is bonded in a linear geometry to one Li1+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one Co4+, and one P5+ atom. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to one Co4+ and one P5+ atom. In the ninth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Co4+ and one P5+ atom. In the tenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one Co4+, and one P5+ atom. In the eleventh O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one Co4+, and one P5+ atom. In the twelfth O2- site, O2- is bonded in a bent 150 degrees geometry to one Co4+ and one P5+ atom. In the thirteenth O2- site, O2- is bonded in a trigonal planar geometry to two Li1+ and one P5+ atom. In the fourteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two P5+ atoms. In the fifteenth O2- site, O2- is bonded in a distorted trigonal pla

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Li4V3P8O29 by Materials Project

Li4V3P8O29 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are eight inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share a cornercorner with one LiO4 tetrahedra, corners with four PO4 tetrahedra, and an edgeedge with one VO6 octahedra. There are a spread of Li–O bond distances ranging from 1.99–2.24 Å. In the second Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share a cornercorner with one LiO4 tetrahedra, corners with four PO4 tetrahedra, and an edgeedge with one VO6 octahedra. There are a spread of Li–O bond distances ranging from 1.99–2.24 Å. In the third Li1+ site, Li1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Li–O bond distances ranging from 1.90–2.31 Å. In the fourth Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share a cornercorner with one LiO4 tetrahedra, corners with four PO4 tetrahedra, and an edgeedge with one VO6 octahedra. There are a spread of Li–O bond distances ranging from 1.88–2.28 Å. In the fifth Li1+ site, Li1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Li–O bond distances ranging from 1.90–2.30 Å. In the sixth Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share a cornercorner with one LiO4 tetrahedra, corners with four PO4 tetrahedra, and an edgeedge with one VO6 octahedra. There are a spread of Li–O bond distances ranging from 1.88–2.28 Å. In the seventh Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share corners with four PO4 tetrahedra and an edgeedge with one VO6 octahedra. There are a spread of Li–O bond distances ranging from 1.87–2.38 Å. In the eighth Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share corners with four PO4 tetrahedra and an edgeedge with one VO6 octahedra. There are a spread of Li–O bond distances ranging from 1.87–2.39 Å. There are six inequivalent V+4.67+ sites. In the first V+4.67+ site, V+4.67+ is bonded to six O2- atoms to form VO6 octahedra that share corners with six PO4 tetrahedra and an edgeedge with one LiO4 tetrahedra. There are a spread of V–O bond distances ranging from 1.83–1.97 Å. In the second V+4.67+ site, V+4.67+ is bonded to six O2- atoms to form VO6 octahedra that share corners with six PO4 tetrahedra and edges with two LiO4 tetrahedra. There are a spread of V–O bond distances ranging from 1.86–2.02 Å. In the third V+4.67+ site, V+4.67+ is bonded to six O2- atoms to form VO6 octahedra that share corners with six PO4 tetrahedra. There are a spread of V–O bond distances ranging from 1.85–1.97 Å. In the fourth V+4.67+ site, V+4.67+ is bonded to six O2- atoms to form VO6 octahedra that share corners with six PO4 tetrahedra. There are a spread of V–O bond distances ranging from 1.85–1.96 Å. In the fifth V+4.67+ site, V+4.67+ is bonded to six O2- atoms to form VO6 octahedra that share corners with six PO4 tetrahedra and an edgeedge with one LiO4 tetrahedra. There are a spread of V–O bond distances ranging from 1.83–1.97 Å. In the sixth V+4.67+ site, V+4.67+ is bonded to six O2- atoms to form VO6 octahedra that share corners with six PO4 tetrahedra and edges with two LiO4 tetrahedra. There are a spread of V–O bond distances ranging from 1.86–2.02 Å. There are sixteen inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two VO6 octahedra, a cornercorner with one PO4 tetrahedra, and corners with two LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 39–47°. There are a spread of P–O bond distances ranging from 1.50–1.63 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two VO6 octahedra, a cornercorner with one PO4 tetrahedra, and corners with two LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 39–47°. There are a spread of P–O bond distances ranging from 1.50–1.63 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two VO6 octahedra, a cornercorner with one LiO4 tetrahedra, and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 41–47°. There are a spread of P–O bond distances ranging from 1.48–1.61 Å. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three VO6 octahedra and a cornercorner with one LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 28–36°. There are a spread of P–O bond distances ranging from 1.48–1.60 Å. In the fifth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three VO6 octahedra and a cornercorner with one LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 28–36°. There are a spread of P–O bond distances ranging from 1.48–1.60 Å. In the sixth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two VO6 octahedra, a cornercorner with one PO4 tetrahedra, and corners with two LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 39–48°. There are a spread of P–O bond distances ranging from 1.48–1.62 Å. In the seventh P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two VO6 octahedra, a cornercorner with one LiO4 tetrahedra, and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 39–43°. There are a spread of P–O bond distances ranging from 1.48–1.60 Å. In the eighth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two VO6 octahedra, a cornercorner with one LiO4 tetrahedra, and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 41–47°. There are a spread of P–O bond distances ranging from 1.48–1.61 Å. In the ninth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two VO6 octahedra, a cornercorner with one PO4 tetrahedra, and corners with two LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 39–41°. There are a spread of P–O bond distances ranging from 1.50–1.61 Å. In the tenth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two VO6 octahedra, a cornercorner with one PO4 tetrahedra, and corners with two LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 39–48°. There are a spread of P–O bond distances ranging from 1.48–1.62 Å. In the eleventh P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two VO6 octahedra, a cornercorner with one LiO4 tetrahedra, and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 39–43°. There are a spread of P–O bond distances ranging from 1.48–1.60 Å. In the twelfth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three VO6 octahedra and corners with two LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 32–36°. There are a spread of P–O bond distances ranging from 1.49–1.59 Å. In the thirteenth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three VO6 octahedra and corners with two LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 32–36°. There are a spread of P–O bond distances ranging from 1.49–1.59 Å. In the fourteenth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two VO6 octahedra, a cornercorner with one PO4 tetrahedra, and corners with two LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 39–41°. There are a spread of P–O bond distances ranging from 1.50–1.61 Å. In the fifteenth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two VO6 octahedra, a cornercorner with one LiO4 tetrahedra, and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 36–41°. There are a spread of P–O bond distances ranging from 1.47–1.61 Å. In the sixteenth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two VO6 octahedra, a cornercorner with one LiO4 tetrahedra, and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 36–41°. There are a spread of P–O bond distances ranging from 1.47–1.61 Å. There are fifty-eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a trigonal planar geometry to two Li1+ and one P5+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one V+4.67+, and one P5+ atom. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two P5+ atoms. In the fourth O2- site, O2- is bonded in a trigonal planar geometry to two Li1+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to one V+4.67+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one V+4.67+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one V+4.67+, and one P5+ atom. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to one V+4.67+ and one P5+ atom. In the ninth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Li1+ and one P5+ atom. In the tenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one V+4.67+, and one P5+ atom. In the eleventh O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one V+4.67+, and one P5+ atom. In the twelfth O2- site, O2- is bonded in a bent 150 degrees geometry to one V+4.67+ and one P5+ atom. In the thirteenth O2- site, O2- is bonded in a bent 150 degrees geometry to one V+4.67+ and one P5+ atom. In the fourteenth O2- site, O2- is bonded in a single-bond geometry to one P5+ atom. In the fifteenth O2- site, O2- is bonded in a single-bond geometry to one P5+ atom. In the sixteenth O2- site, O2- is bonded in a bent 150 degrees geometry to one V+4.67+ and one P5+ atom. In the seventeenth O2- site, O2- is bonded in a bent 150 degrees geometry to one V+4.67+ and one P5+ atom. In the eighteenth O2- site, O2- is bonded in a bent 150 degrees geometry to one V+4.67+ and one P5+ atom. In the nineteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one V+4.67+, and one P5+ atom. In the twentieth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two P5+ atoms. In the twenty-first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Li1+ and one P5+ atom. In the twenty-second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Li1+ and one P5+ atom. In the twenty-third O2- site, O2- is bonded in a bent 150 degrees geometry to one V+4.67+ and one P5+ atom. In the twenty-fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one V+4.67+ and one P5+ atom. In the twenty-fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one V+4.67+, and one P5+ atom. In the twenty-sixth O2- site, O2- is bonded in a bent 150 degrees geometry to one V+4.67+ and one P5+ atom. In the twenty-seventh O2- site, O2- is bonded in a bent 150 degrees geometry to one V+4.67+ and one P5+ atom. In the twenty-eighth O2- site, O2- is bonded in a trigonal planar geometry to two Li1+ and one P5+ atom. In the twenty-ninth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Li1+ and one P5+ atom. In the thirtieth O2- site, O2- is bonded in a bent 150 degrees geometry to one V+4.67+ and one P5+ atom. In the thirty-first O2- site, O2- is bonded in a distorted trigonal pla

36 MATERIALS SCIENCE↗
DOE OSTI2022

Designing a Particle Flow Control Apparatus

Flow control within a particle-based Concentrated Solar Power (CSP) system is essential in determining the heat transfer coefficient, and therefore, the power generation capability of these systems. There are three areas where particle flow control is significant: the receivers, storage tanks, and particle-sCO2 heat exchangers. The focus of this work is on designing a new mechanism to control the flow in the particle-sCO2 heat exchangers due to the simplicity and potential cost savings when compared to the other areas of interest. The goal is for this new design to have quicker response times in terms of particle flowrate than a slide gate or flow control valve, which are designs currently used. The design resembles that of a chuck mechanism within a drill where a rotation of the sleeve elicits movement of the jaws both vertically and horizontally to close the outlet area of the nozzle. Additionally, this design will utilize the current actuator that is already used within these heat exchangers to reduce the complexity of implementation. The jaws are designed to be closed at an angle of 76˚ which is just slightly steeper than the hopper leading to the mechanism. Furthermore, this design can be tuned to limit particle bridging and other particle flow phenomena that result in blockages. The prototypes were 3D printed out of polylactic acid (PLA) and scaled up to 100%, 200%, and 400% to be able to observe the velocity profiles of the mechanism more clearly. Experiments are performed with this prototype to compare the inlet and outlet mass flow rates at different configurations of the jaws. The particles used in these experiments are 0.3mm HSP 40/70 that are commonly used in particle-based CSP systems.

14 SOLAR ENERGY↗