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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 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Polymer Precursor Derived Li x PON Electrolytes: Toward Li–S Batteries

Efforts to develop polymer precursor electrolytes that offer properties anticipated to be similar or superior to (lithium phosphorus oxynitride, LiPON) glasses are reported. Such precursors offer the potential to be used to process LiPON-like thin glass/ceramic coatings for use in all solid state batteries, ASBs. Here, LiPON glasses provide a design basis for the synthesis of sets of oligomers/polymers by lithiation of OP(NH 2 ) 3–x (NH) x [from OP(NH) 3 ],OP(NH 2 ) 3-x (NHSiMe 3 ) x and [P=N] 3 (NHSiMe 3 ) 6–x (NH) x . Furthermore, the resulting systems have degrees of polymerization of 5–20. Treatment with selected amounts of LiNH 2 provides varying degrees of lithiation and Li + conducting properties commensurate with Li + content. Polymer electrolytes impregnated in/on Celgard exhibit Li + conductivities up to ~1 × 10 –5 S cm –1 at room temperature and are thermally stable to ~150 °C. A Li–S battery assembled using a Li 6 SiPON composition polymer electrolyte exhibits an initial reversible capacity of 1500 mAh g sulfur –1 and excellent cycle performance at 0.25 and 0.5 C rate over 120 cycles at room temperature.

25 ENERGY STORAGE↗
NASA NTRS1986

Polymer precursors for SiC ceramic materials

Work on precursor polymers to SiC was performed, concentrating on polymers made from decamethyl cyclohexasilyene units. The initial approach was to synthesize mixed diphenyl decamethyl cyclohexasilane, dephenylate, and polymerize. This produced polymers which had yields of up to 50 percent SiC. (Theoretical yield is 75 percent). The present approach is to make the polymer through the intermediate trans-1,4-diphenyl decamethyl cyclohexasilane. This should produce a crystalline polymer and high strength fibers. These will be thermally decomposed to SiC fibers. This requires new chemistry which is currently being studied.

Litt, Morton H.↗
DOE OSTI2020

Design, Synthesis, and Characterization of Polymer Precursors to Li x PON and Li x SiPON Glasses: Materials That Enable All-Solid-State Batteries (ASBs)

LiPON-like glasses that form lithium dendrite impenetrable interfaces between lithium battery components are enabling materials that may replace liquid electrolytes permitting production of all-solid-state batteries (ASBs). Unfortunately, to date, such materials are introduced only via gas-phase deposition. Furthermore, we demonstrate the design and synthesis of easily scaled, lowtemperature, low-cost, solution-processable inorganic polymers containing LiPON/LiSiPON elements. OPCl 3 and hexachlorophosphazene [Cl 2 P=N] 3 provide starting points for elaboration using MNH 2 (M = Li/Na) or (Me 3 Si)NH followed by reaction with controlled amounts of LiNH 2 to produce oligomers/polymers with molecular weights (MWs) ≈1–2 kDa characterized by multinuclear NMR, gel permeation chromatography (GPC), thermogravimetric analysis (TGA), Fourier-transform infrared (FTIR), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and matrix-assisted laser desorption/ ionization (MALDI)-time-of-flight (ToF) offering stabilities to 150–200 °C and ceramic yields (800 °C) of 50–60%. 7 Li NMR suggests that precursor-bound Li + dissociates easily, beneficial for electrochemical applications. XPS shows higher N/P ratios (1–3) than via gas-phase methods (<1) correlating N/P ratios, 7 Li shifts, and Li + conductivities. Li 2 SiPHN offers the highest ambient conductivity of 3 × 10 –1 mS cm –1 at 400 °C/2 h/N 2 .

36 MATERIALS SCIENCE↗
NASA NTRS1990

Isomeric Trisaryloxycyclotriphosphazene Polymer Precursors

Substances useful for making heat-and fire-resistant polymers. Cyclotriphosphazene-based monomers and polymer precursors led to development of high-temperature materials. Cyclotriphosphazene-derived monomers, polymer precursors, and polymers becoming important from both industrial and scientific points of view. Presence of phosphazene moiety in cyclotriphosphazene-based monomers and polymer precursors expected to impact special properties in desired high-performance materials containing inorganic backbones for aerospace applications. Useful for obtaining heat-and fire-resistant polymers for composites, adhesives, molding powders, and coating laminates. Also used in structures (e.g. secondary structures in aircraft), in construction of spacecraft, and in electronics and computer industries.

St. Clair, Terry L.↗
NASA NTRS1993

Ceramic fibers from Si-B-C polymer precursors

Non-oxide ceramics such as silicon carbide (SiC), silicon nitride (Si3N4), and silicon borides (SiB4, SiB6) have thermal stability, oxidation resistance, hardness, and varied electrical properties. All these materials can be prepared in a fiber form from a suitable polymer precursor. The above mentioned fibers, when tested over a temperature range from 25 to 1400 C, experience degradation at elevated temperatures. Past work in ceramic materials has shown that the strength of ceramics containing both carbides and borides is sustained at elevated temperatures, with minimum oxidation. The work presented here describes the formation of ceramic fibers containing both elements, boron and silicon, prepared via the polymer precursor route previously reported by the authors, and discusses the fiber mechanical properties that are retained over the temperature range studied.

Riccitiello, S. R.↗
DOE OSTI2023

Synthesis of high-entropy carbides from multi-metal polymer precursors

Three compositions of high-entropy carbides, (TiHfVNbTa)C, (TiZrHfNbTa)C and (TiZrNbTaW)C were synthesized via a modified Pechini process, in which citric acid served as both a cation chelating agent and a carbon source. Through pyrolysis and spark plasma sintering, single phase high-entropy carbides were formed from the homogeneous precursors at a relatively low temperature of 1800 °C. The dispersion of cations in the polymer precursor facilitated shorter diffusion distances in polymer-derived materials, and thus compositional homogeneity was significantly improved relative to materials produced by a solid-state method, as quantified by a defined coefficient of variation applied to energy-dispersive X-ray spectroscopy. Finally, a finer microstructure in polymer-derived materials results in improved fracture toughness with a K IC value of 4.29 MPa·m 1/2 achieved for (TiHfVNbTa)C.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Characterization of lignin-degrading enzyme PmdC, which catalyzes a key step in the synthesis of polymer precursor 2-pyrone-4,6-dicarboxylic acid

Pyrone-2,4-dicarboxylic acid (PDC) is a valuable polymer precursor that can be derived from the microbial degradation of lignin. The key enzyme in the microbial production of PDC is 4-carboxy-2-hydroxymuconate-6-semialdehyde (CHMS) dehydrogenase, which acts on the substrate CHMS. We present the crystal structure of CHMS dehydrogenase (PmdC from Comamonas testosteroni) bound to the cofactor NADP, shedding light on its three-dimensional architecture, and revealing residues responsible for binding NADP. Using a combination of structural homology, molecular docking, and quantum chemistry calculations, we have predicted the binding site of CHMS. Key histidine residues in a conserved sequence are identified as crucial for binding the hydroxyl group of CHMS and facilitating dehydrogenation with NADP. Mutating these histidine residues results in a loss of enzyme activity, leading to a proposed model for the enzyme's mechanism. These findings are expected to help guide efforts in protein and metabolic engineering to enhance PDC yields in biological routes to polymer feedstock synthesis.

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

Metal-like Charge Transport in PEDOT(OH) Films by Post-processing Side Chain Removal from a Soluble Precursor Polymer

Herein, a route to produce highly electrically conductive doped hydroxymethyl functionalized poly(3,4-ethylenedioxythiophene) (PEDOT) films, termed PEDOT(OH) with metal-like charge transport properties using a fully solution processable precursor polymer is reported. Further, this is achieved via an ester-functionalized PEDOT derivative [PEDOT(EHE)] that is soluble in a range of solvents with excellent film-forming ability. PEDOT(EHE) demonstrates moderate electrical conductivities of 20–60 S cm -1 and hopping-like (i.e., thermally activated) transport when doped with ferric tosylate (FeTos 3 ). Upon basic hydrolysis of PEDOT(EHE) films, the electrically insulative side chains are cleaved and washed from the polymer film, leaving a densified film of PEDOT(OH). These films, when optimally doped, reach electrical conductivities of ≈1200 S cm -1 and demonstrate metal-like (i.e., thermally deactivated and band-like) transport properties and high stability at comparable doping levels.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

Scalable Polymer Precursor Based LiPON Type Li-Metal Interface Enabled High Performance Li-Sulfur Battery

The Battery 500 program objective is to research, develop, and demonstrate lithium battery technologies capable of achieving 500 Wh/kg with stable lifetime of 1000 cycles. This Battery 500 seedlings project has demonstrated a new approach and a pathway toward the program’s goals in just one awarded and executed phase. Cells have been assembled, tested, and evaluated. This report details efforts to develop polymer precursor electrolytes that offer properties anticipated to be similar or superior to LiPON glasses. Such precursors offer the potential to be used to process LiPON-like thin glass/ceramic coatings for use in lithium batteries. LiPON glasses provide a design basis for the synthesis of sets of oligomers/polymers by lithiation of OP(NH 2 ) 3-x (NH) x [from OP(NH) 3 ], OP(NH 2 ) 3-x (NHSiMe 3 ) x and [P=N] 3 (NHSiMe 3 ) 6-x (NH) x . Polymer electrolytes impregnated in/on celgard exhibit Li+ conductivities up to ~1×10 -5 S/cm at room temperature and are thermally stable to ≈150 °C. A Li-S battery assembled using a Li 6 SiPON composition polymer electrolyte exhibits an initial reversible capacity of 1500 mAh/g sulfur and excellent cycle performance at 0.25 and 0.5 C rate over 120 cycles, declining to 750 mAh/g at after a 220 h test period. At the same time, computational studies were performed to understand the conduction mechanism of LIPON and its interaction with Li metal. These initial project results provide a foundation for further development of the system to achieve the program goal.

25 ENERGY STORAGE↗
NASA NTRS1986

Polymer precursors for ceramic matrix composites

The synthesis and characterization of a polycyclohexasilane is reported. Because of its cyclic structure, it is anticipated that this polymer might serve as a precursor to SIC having a high char yield with little rearrangement to form small, volatile cyclic silanes, and, as such, would be of interest as a precursor to SiC composite matrices and fibers, or as a binder in ceramic processing. Several approaches to the synthesis of a bifunctional cyclic monomer were attempted; the most successful of these was metal coupling of PhMeSiCl2 and Me2SiCl2. The procedure gives six-membered ring compounds with all degrees of phenyl substitution, from none to hexaphenyl. The compounds with from 0-2 groups were isolated and characterized. The fraction with degree of phenyl substitution equal to 2, a mixture of cis and trans 1,2-; 1,3-; and 1,4 isomers, was isolated in 32 percent yield. Pure 1,4 diphenyldecamethylcyclohexasilane was isolated from the mixed diphenyl compounds and characterized. Diphenyldecamethylcyclohexasilanes were dephenylated to dichlorodecamethylcyclohexasilanes by treating with H2SO4.NH4Cl in benzene. The latter were purified and polymerized by reacting with sodium in toluene. The polymers were characterized by HPGPC, elemental analysis, proton NMR, and IR. Thermogravimetric analyses were carried out on the polymers. As the yield of residual SiC was low, polymers were heat treated to increase the residual char yield. As high as 51.52 percent residual char yield was obtained in one case.

Litt, M. H.↗
DOE OSTI2022

Catalytic conversion of high S-lignin to a sustainable tri-epoxide polymer precursor

More than 40 million tons of thermosetting plastics are produced annually and 70% of those are epoxy polymers. The synthesis of bio-based epoxide provides a pathway for making renewable thermoset plastics. We describe in this study the use of a genetically modified high-S poplar lignin to produce 4-propyl-2,6-dimethoxyphenol (DMPP), which is converted to the tri-functional compound propylpyrogallol (DMPPO) by a reaction catalysed by N 2 O 5 in the green solvent water. The resulting DMPPO can be converted to a novel tri-epoxide by reaction with epichlorohydrin. Native high-S lignin as well as several organosolv lignins extracted from this poplar biomass were investigated as feedstocks. Notably, direct reductive catalytic fractionation (RCF) of the high-S poplar wood over Pd–Zn/C catalyst with Pd : Zn ratio 1 : 10 at 225 °C under 35 bar H 2 in methanol gave the highest yield of biophenol monomers from the lignin present, the major product being DMPP. Under optimized conditions, conversion of DMPP to DMPPO over the Nb 2 O 5 was nearly quantitative (96% yield), and this conversion could be made without extensive prior purification of the DMPP. The Nb 2 O 5 catalyst could be recycled several times before significant deactivation. This sequence of two catalytic reactions demonstrates that the production of epoxides from lignin-derived DMPPO is a realistic strategy for making renewable polymer building blocks from biomass.

09 BIOMASS FUELS↗
DOE OSTI2023

Towards Automated Design of Polymer Precursors for Rational Design of Porous Carbon-Materials [Slides]

Overview: Developed capability enables easy building of realistic polymer structures and a straightforward evaluation of polymer properties using different computational approaches. Topics of relevance to LANL mission: fundamental understanding of gas, vapor, ion, and liquid transport in polymer materials with applications in carbon capture, clean energy, hydrogen production (e.g., fuel cells and electrolyzes); Toxic element removal; Design of polymer binders in explosives. Workforce Development: Project provided a valuable opportunity to for a PI to manage a LANL research effort, expand collaborations (e.g., MPA division), and establish research topic that aligns with the LANL mission; The capability built was highlighted in the proposal "Versatile Polyolefins-Based Ionomer Platform for Next Generation Polymer Electrolyte Membrane and Hydrogen Production" lead by InnoSense LLC in collaboration with MPA-1 and T-1 as a response to DOE's call DE-FOA-0003003: Science Foundations for Energy Earthshots.

36 MATERIALS SCIENCE↗
NASA NTRS2014

Processing and Characterization of Basalt Fiber Reinforced Ceramic Composites for High Temperature Applications Using Polymer Precursors

The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, which allows a shape to be formed prior to the cure, and is then pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The two PDCs used in this development are polysiloxane and polycarbosilane. Basalt fibers are used for the reinforcement in the composite system. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in composites. Continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material.

High Temperature Composites↗
NASA NTRS1986

Polymer precursors for ceramic composites

The fiber composite approach to reinforced ceramics provides the possibility of achieving ceramics with high fracture toughness relative to monolithics. Fabrication of ceramic composites, however, demands low processing temperatures to avoid fiber degradation. Formation of complex shapes further requires small diameter fibers as well as techniques for infiltrating the matrix between fibers. Polymers offer low temperature processability, control of rheology not available with ceramic powders, and should serve as precursors to matrix fibers. In recent years, a number of polysilanes and polysilezanes were investigated as potential presursors. A review of candidate polymers is presented, including recent studies of silsesquioxanes.

Hurwitz, Frances I.↗
NASA NTRS2014

Processing and Characterization of Basalt Fiber Reinforced Ceramic Composites for High Temperature Applications Using Polymer Precursors

The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed, to be cured, and be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The two PDCs used in this development are polysiloxane and polycarbosilane. Polysiloxanes contain a silicon oxycarbide backbone when pyrolized up to 1000degC. Polycarbosilane, an organosilicon polymer, contain a silicon-carbon backbone; around 1200degC, -SiC begins to crystallize. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in composites. Basalt is a naturally occurring material found in volcanic rock. Continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. Testing for this included thermal and mechanical testing per ASTM standard tests.

High Temperature Composites↗
NASA NTRS2014

Processing and Characterization of Basalt Fiber Reinforced Ceramic Composites for High Temperature Applications Using Polymer Precursors

The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The two PDCs used in this development are polysiloxane and polycarbosilane. Polysiloxanes contain a silicon oxycarbide backbone when pyrolized up to 1000C. Polycarbosilane, an organosilicon polymer, contain a silicon-carbon backbone; around 1200C, beta-SiC begins to crystallize. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in composites. Basalt is a naturally occurring material found in volcanic rock. Continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. Thermal and mechanical testing includes oxyacetylene torch testing and three point bend testing.

Ceramic Matrix Composites↗
NASA NTRS2014

Processing and Characterization of Basalt Fiber Reinforced Ceramic Composites for High Temperature Applications Using Polymer Precursors

The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The two PDCs used in this development are polysiloxane and polycarbosilane. Polysiloxanes contain a silicon oxycarbide backbone when pyrolized up to 1000 deg C. Polycarbosilane, an organosilicon polymer, contain a silicon-carbon backbone; around 1200 deg C, Beta-SiC begins to crystallize. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in composites. Basalt is a naturally occurring material found in volcanic rock. Continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. Thermal and mechanical testing includes oxyacetylene torch testing and three point bend testing.

Polymer Derived Ceramics↗
NASA NTRS2019

Monolithic Trace-Contaminant Sorbents Fabricated from 3D-Printed Polymer Precursors

The current trace-contaminant (TC) removal technology for use in Extravehicular Activities (EVAs) involves the use of a packed bed of acid-impregnated granular charcoal, which is difficult to regenerate. In this paper, results are presented on the development of vacuum-regenerable TC sorbents for use in the Portable Life Support System (PLSS). The sorbents are derived from 3D-printed polymer monoliths (e.g., honeycomb structures), which are then carbonized and activated in order to develop porosity, and also to enhance the TC-sorption capacity. Results are presented on the following aspects of carbon-sorbent development: (1) precursor selection; (2) monolith fabrication; (3) shape retention and strength; (4) carbon surface and porosity characterization; (5) TC-sorption capacity and vacuum-regeneration; (6) pressure drop; and (7) sub-scale sorbent prototype. The use of predominantly microporous monolithic carbon is associated with the following benefits: (a) high TC-sorption capacity; (b) low pressure drop; (c) rapid vacuum (pressure-swing) desorption due to thin monolith walls and low pressure drop; (d) good thermal management (high thermal conductivity and low adsorption/desorption thermal effects associated with physisorption); and (e) good resistance to dusty environments.

Portable Life Support System (PLSS)↗