Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “polymerization”

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 559 records · Page 31
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Ion transport in polymerized lyotropic liquid crystals containing ionic liquid

In this work, we investigate the effect of morphology and segmental dynamics on ion transport in polymerized lyotropic liquid crystals (polyLLCs) containing 1-butyl-3-methylimidazolium tetrafluoroborate as ionic liquid (IL). We demonstrate that two important factors, which affect ion conduction in polyLLCs, are grain size and chain density at the interface. The polyLLC with large grain size (70 nm) shows significant reduction in ion conductivity (one order of magnitude) compared to its homopolymer/IL mixture. However, the polyLLC with small grain size (20 nm) has little difference in ion conductivity compared to its homopolymer/IL mixture. It is observed that decreasing the chain density enhances the interaction of IL with polymer chains and consequently slows the relaxation of polymer chains. Finally, in addition, comparing the dynamics of polymer chains in mixtures of homopolymer/IL and templated LLC mesophases shows that the confinement in LLC structure prolongs the relaxation of polymer chains.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Polymeric spatial resolution test patterns for mass spectrometry imaging using nano-thermal analysis with atomic force microscopy

As the spatial resolution of mass spectrometry imaging technologies has begun to reach into the nanometer regime, finding readily available or easily made resolution reference materials has become particularly challenging for molecular imaging purposes. This study describes the fabrication, characterization and use of vertical line array polymeric spatial resolution test patterns for nano-thermal analysis/atomic force microscopy/mass spectrometry chemical imaging.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

IR Spectroscopy for the Analysis of Scattering Polymeric Materials{sup *}

An effective spectroscopic method for estimating the degree of filling (porosity) of polymeric materials, the average size and the size distribution of the scattering particles of the filler within the polymer matrix, their anisotropy and the degree of orientation is proposed. The obtained spectral data are in good agreement with the results of optical and electron microscopy methods.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Methodologies and strategies for detecting fiber orientation in polymeric fiber-reinforced composites

In this review paper different methods and techniques for representing fiber orientation in advanced polymer matrix composites are presented. A description of the effect of fiber orientation on processing, fabrication and mechanical properties of a composite material is presented. The paper discusses the mathematical modeling and modeling techniques for fiber structure representation in polymeric composites, with an emphasis on fiber orientation in a composite part. The paper is divided into two sections; namely—destructive techniques and non-destructive techniques. The capabilities and limitations of each technique with respect to fiber orientation detection and measurements are discussed.

composites↗
DOE OSTI2018

A Novel Hyperbranched Polymeric Flocculant for Waste-Water Treatment

Cationic hyperbranched oligomer poly(N-acryloyl-1,2-diaminoethane hydrochloride) (HADE) was firstly synthesized by Michael addition reaction. And then, a series of cationic flocculants poly(acrylamide/N-acryloyl-1,2-diaminoethane hydrochlorides) (PAM-HADEs) with hyperbranched structure was prepared from HADE as macro-monomer and acrylamide (AM). The structures of PAM-HADEs were characterized by Fourier transform infrared spectrometry, {sup 1}H and {sup 13}C nuclear magnetic resonance spectroscopy, gel permeation chromatography (GPC) and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF). And the properties were systematically evaluated by intrinsic viscosity, zeta potential and hydrodynamic radius. The mechanism of the cationic hyperbranched copolymer used in water treatment was extensively studied via a jar test in which the transmittance of the supernatant, settling time, and average floc size were used to evaluate the flocculability. Compared with the linear flocculant poly (acrylamide/liner-N-acryloyl-1,2-diaminoethane hydrochloride) (PAM-LADE), the novel hyperbranched polymeric flocculants exhibited outstanding flocculability which were reflected by shorter settlement time, high transmittance and large floc size. The primary cause that PAM-HADEs owned excellent flocculability is the more stretching configuration and less chains entanglement of PAM-HADEs in waste-water due to their hyperbranched structure compared with that of the linear PAM-LADE which exhibited curly coil configuration. On the other hand, abundant and exposed cationic terminal groups of PAM-HADEs originated from their hyperbranched structure also hint higher flocculation capacity. At optimum dosages of the polymer, the transmittance of the supernatant is less at low and high pH values, indicating that the natural pH (pH 7.29) of the suspension is the most appropriate pH for the flocculation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Removal of Iron and Copper Ions from the Liquid Phase by Modified Polymeric Membranes

Preparation of polymeric membranes based on cellulose acetate and modified by adding different amounts of a pore generating agent, which was polyvinylpyrrolidone (PVP), is presented and potential application of the membranes obtained for the removal of iron and copper ions from liquid phase is examined. Addition of various amounts of PVP has an impact on the physical (porosity, equilibrium water content and permeability) and chemical (content of the surface oxygen group, pH) properties of the membranes obtained. Filtration of iron and cupper solution leads to significant changes in the total content of surface oxygen groups, however the acidic oxygen groups remain dominant. With the content of PVP increasing within a certain range, the membrane permeability is improved. The membranes obtained show higher efficiency in removal of Fe{sup 3+} than Cu{sup 2+} ions, but with increasing content of PVP the efficiency in iron ions removal decreases and the total filtration resistance decreases after filtration of iron ions solutions.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Substrate-induced luminescence response of terbium-containing polymeric vesicles doped with the tetra- and bis-1,3-diketone derivatives of calix[4]arenes bearing nonyl substituents at the lower rims

Polymeric aggregates (~100 nm) based on polydiacetylenic acid doped with the luminescent Tb{sup III} complexes with the tetra- and bis-1,3-diketonate derivatives of calix[4]arenes with nonyl substituents at the lower rims are considered as potential nanosensors. The obtained colloidally stable mixed aggregates can generate a substrate-induced luminescent response in aqueous solutions of 2,2´,6´,2´´-terpyridine in the micromolar concentration range due to the coordination of the latter by Tb{sup III} ions on the aggregate surface.

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

Synthesis and biological activity of new polymeric silver-containing nanocomposites

The formation of new polymeric nanocomposites with silver nanoparticles incorporated into the matrix of 1-vinyl-1,2,4-triazole copolymers with vinyl acetate was studied. Water-soluble nanocomposites containing different amounts of silver nanoparticles with an average size of 6–13 nm were synthesized varying the reaction conditions. The physicochemical, optical, thermal, and structural properties of the nanocomposites were studied by IR and UV spectroscopy, transmission electron microscopy, X-ray diffraction and atomic absorption analyses, and thermogravimetry. The antimicrobial activity of the initial copolymers and related nanocomposites was evaluated with respect to test microorganisms.

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

Effect of Topology on Transient Dynamic and Shock Response of Polymeric Lattice Structures

Architected cellular materials, such as lattice structures, offer potential for tunable mechanical properties for dynamic applications of energy absorption and impact mitigation. In this work, the static and dynamic behavior of polymeric lattice structures was investigated through experiments on octet-truss, Kelvin, and cubic topologies with relative densities around 8%. Here, dynamic testing was conducted via direct impact experiments (25–70 m/s) with high-speed imaging coupled with digital image correlation and a polycarbonate Hopkinson pressure bar. Mechanical properties such as elastic wave speed, deformation modes, failure properties, particle velocities, and stress histories were extracted from experimental results. At low impact velocities, a transient dynamic response was observed which was composed of a compaction front initiating at the impact surface and additional deformation bands whose characteristics matched low strain-rate behavior. For higher impact velocities, shock analysis was carried out using compaction wave velocity and Eulerian Rankine–Hugoniot jump conditions with parameters determined from full-field measurements.

36 MATERIALS SCIENCE↗
DOE OSTI2018

A water-soluble precursor for efficient silica polymerization by silicateins

Highlights: • New water-soluble silica acid precursor was suggested. • New precursor was highly effective with silicatein A1. • Optimal conditions for the silicatein activity were determined. Silicateins, the spicule-forming proteins from marine demosponges capable to polymerize silica, are popular objects of biomineralization studies due to their ability to form particles varied in shape and composition under physiological conditions. Despite the occurrence of the many approaches to nanomaterial synthesis using silicateins, biochemical properties of this protein family are poorly characterized. The main reason for this is that tetraethyl orthosilicate (TEOS), the commonly used silica acid precursor, is almost insoluble in water and thus is poorly available for the protein. To solve this problem, we synthesized new water-soluble silica precursor, tetra(glycerol)orthosilicate (TGS), and characterized biochemical properties of the silicatein A1 from marine sponge Latrunculia oparinae. Compared to TEOS, TGS ensured much greater activity of silicatein and was less toxic for the mammalian cell culture. We evaluated optimum conditions for the enzyme - pH range, temperature and TGS concentration. We concluded that TGS is a useful silica acid precursor that can be used for silica particles synthesis and in vivo applications.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Investigation of composition, structure and bioactivity of extracellular polymeric substances from original and stress-induced strains of Thraustochytrium striatum

This paper was the first to study extracellular polymeric substances (EPSs) of Thraustochytrium striatum on composition, structure and bioactivities. Two strains of T. striatum including original (ori) and high-biomass (mut) strains (induced by high-nitrogen stress) were compared. The EPSs from both strains mainly contained polysaccharide (41–64%, w/w, dry basis) and protein (25–40%, w/w, dry basis), which was shown by the morphology study with an AFM. The monosaccharide profile of the EPS polysaccharide was consisted of glucose, galactose, arabinose, and trace amount of xylose. Glucose and arabinose took up to 82–90% (w/w, dry basis) of the total polysaccharide. The structure and functional groups of EPSs were determined by FTIR and NMR. The NMR results revealed that the major structural linkages of the polysaccharides of both ori and mut EPSs were 1 → 6-β-glucan and 1 → 4-α-galactan branched with l-α-arabinose. The EPSs were found to have anti-tumor activities against mouse melanoma B16-F0, human prostate carcinoma DU145, human cervical carcinoma HeLa, and human lung carcinoma A549. The EPSs also showed antioxidant and anti-inflammatory activities and antibacterial activity against Pseudomonas aeruginosa.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Tackling issues of lithium metal anodes with a novel polymeric lithicone coating

Lithium metal (Li) has been hindered from as anodes in commercial batteries for over 50 years, due to two main issues: continuous formation of solid electrolyte interphase (SEI) and lithium dendritic growth. In this work, we report a new strategy to tackle these issues, i.e., using molecular layer deposition (MLD) to grow an ionically conducting but electrically insulating polymeric lithicone coating, an Li-containing triethanolamine (LiTEA). Our electrochemical tests revealed that this LiTEA coating could serve as an exceptional protection layer over Li anodes. Consequently, the LiTEA-coated Li electrodes could achieve a superior cyclability of > 10000 Li stripping/plating cycles at a current density of 5 mA cm -2 and a long cyclability of > 5500 cycles at 2 mA cm -2 in Li||Li symmetric cells without failures, under a fixed areal capacity of 1 mAh cm -2 . Characterizations using scanning electron microscopy and X-ray photoelectron microscopy verified that Li + ions could be easily extracted through and deposited under the LiTEA coating during the stripping/plating processes. Consequently, this LiTEA coating significantly inhibited the formation of SEI and Li dendrites. This underlies the long cycling lifetime of the LiTEA-coated Li||Li cells. Coupling with the nickel-rich LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811) cathodes, more encouragingly, the LiTEA-coated Li anodes could remarkably extend the cyclability and sustainable capacity of the resultant Li||NMC full cells. Finally, we also demonstrated that the performance of Li||NMC cells could be further improved through combining an LiTEA-coated Li anode with an Li 2 S-modified NMC811 via atomic layer deposition (ALD). Thus, this study is inspiring for developing high-energy Li||NMC lithium metal batteries.

25 ENERGY STORAGE↗
DOE OSTI2021

In situ formation of polymer-inorganic solid-electrolyte interphase for stable polymeric solid-state lithium-metal batteries

Composite polymer electrolytes (CPEs) for solid-state Li-metal batteries (SSLBs) still suffer from gradually increased interface resistance and unconstrained Li-dendrite growth. Herein, we addressed the challenges by designing a LiF-rich inorganic solid-electrolyte interphase (SEI) through introducing a fluoride-salt-concentrated interlayer on CPE film. The rigid but flexible CPE helps accommodate the volume change of electrodes, while the polymeric highly concentrated electrolyte (PHCE) surface-layer regulates Li-ion flux due to the formation of a stable LiF-rich SEI via anion reduction. The designed CPE-PHCE presents enhanced ionic conductivity and high oxidation stability of >5.0 V (versus Li/Li + ). Furthermore, it dramatically reduces the interfacial resistance and achieves a high critical current density of 4.5 mA cm –2 . The SSLBs, fabricated with thin CPE-PHCE membranes (<100 μm) and Co-free LiNiO 2 cathodes, exhibit exceptional electrochemical performance and long cycling stability. Lastly, this approach of SEI design can also be applied to other types of batteries.

25 ENERGY STORAGE↗
DOE OSTI2025

Crosslinked polymeric ionic liquid stationary phases incorporating a combination of silver(I) and copper(II) ions for olefin separations by gas chromatography

The development of efficient and selective olefin separation technologies is a critical challenge within the chemical industry given the high energy demands of conventional cryogenic distillation methods. To address this, the study explores the effectiveness of polymeric ionic liquid (PIL) stationary phases in gas chromatography (GC) that incorporate both silver(I) ([Ag + ]) and copper(II) ([Cu 2+ ]) ions for enhanced olefin separation via π-complexation interactions. Further, the effects of both non-crosslinked and crosslinked PIL stationary phases containing varying ratios of [Ag⁺] and [Cu²⁺] ions were systematically investigated to evaluate their impact on the separation of olefins from paraffins and structurally similar olefins. Retention measurements using a broad range of olefinic probes revealed that [Ag⁺] ions provided stronger and more consistent π-complexation in PIL-based stationary phases, while [Cu²⁺] ions preferentially enhance olefin retention in crosslinked systems. Furthermore, thermal stability studies showed that [Ag + ]-containing PIL stationary phases maintain stable olefin separation efficiency over prolonged exposure under elevated temperatures, while crosslinked PIL stationary phases containing [Cu 2+ ] ions exhibited stronger retention due to increased surface adsorption. These findings provide insight into the tunability of metal–olefin interactions using PIL-based stationary phases and suggest design strategies for achieving thermally stable and highly selective chromatographic separations of unsaturated hydrocarbons.

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

Polyaniline-based all-polymeric adhesive layer: An effective lightning strike protection technology for high residual mechanical strength of CFRPs

Carbon fiber reinforced plastics (CFRPs) are vulnerable to lightning strikes due to their low electrical conductivity and low heat resistance. A lightning strike can damage CFRP structure catastrophically. Most common lightning strike protection (LSP) technology, consists of expanded metal foils/films on top of composite structures. This technology possesses disadvantages such as increased weight, galvanic corrosion, expensive integration and repair costs. In the present study, authors introduce a novel, easy to apply and all-polymeric LSP material. A doped intrinsic conductive polymer i.e. Polyaniline (PANI) dispersed in a thermosetting cross-linking polymer divinylbenzene (DVB) has been used to prepare an adhesive layer of 0.25–0.4 mm thickness. CFRP structure coated with PANI-based LSP layer, when tested against simulated lightning impulse current of 100 kA, demonstrated effective dissipation of the current, rendering almost 100% safety to the CFRP structure. PANI showed the capability to create a 3-D conductive network due to its self-assembling property, which makes it superior compared to its counterpart carbon/metal nano-filler based LSP technologies. Almost 100% residual strength of PANI-LSP protected CFRPs is reported in this work.

42 ENGINEERING↗
DOE OSTI2016

Effects of CeO{sub 2} nanoparticles on sludge aggregation and the role of extracellular polymeric substances – Explanation based on extended DLVO

The extended DLVO (XDLVO) theory was applied to elucidate the potential effects of CeO{sub 2} nanoparticles (CeO{sub 2} NPs) on sludge aggregation and the role of extracellular polymeric substances (EPS). In this study, seven different concentrations of CeO{sub 2} NPs were added to activated sludge cultured in sequencing batch reactors (SBRs) and compared with a control test that received no CeO{sub 2} NPs. After exposure to 50 mg/L CeO{sub 2} NPs, a negligible change (p>0.1) occurred in the sludge volume index (SVI), whereas the flocculability and aggregation of the sludge decreased by 18.8% and 11.2%, respectively, resulting in a high effluent turbidity. The XDLVO theory demonstrated that the adverse effects of the CeO{sub 2} NPs on sludge aggregation were due to an enhanced barrier energy. Compared to the van der Waals energies (W{sub A}) and the electric double layer (W{sub R}), the acid-base interaction (W{sub AB}) markedly changed for the various concentrations of CeO{sub 2} NPs. The EPS played a decisive role in the sludge surface characteristics, as the removal of EPS equals to the negative effects induced by 5–10 mg/L CeO{sub 2} NPs on the sludge flocculability and aggregation. The presence of CeO{sub 2} NPs induced negative contributions to the tight boundary EPS (TB-EPS) and core bacteria while positive contributions to the total interaction energy of the loose boundary EPS (LB-EPS). - Highlights: • CeO{sub 2} NPs adversely affected the flocculability and aggregation of the sludge. • The presence of CeO{sub 2} NPs increased the energy barrier and led to a stable suspension. • The removal of EPS equals to the negative effects induced by 5–10 mg/L CeO{sub 2} NPs. • The acid-base interaction was dominate and markedly changed for the CeO{sub 2} NPs. • CeO{sub 2} NPs induced negative contributions to the TB-EPS while positive to the LB-EPS.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

Influence of CeO2 nanoparticles on viscoelastic properties of sludge: Role of extracellular polymeric substances

Highlights: • Steady shear flow and dynamic sweep tests were conducted for sludge rheology. • Less than 5 mg/L CeO{sub 2} NPs increased sludge flowability, being opposite to 20 mg/L. • The removal of EPSs weakened elastic and solid-like properties of sludge. • The removal of EPSs increased repulsive forces and reduced hydrophobic interaction. Cerium oxide nanoparticles (CeO{sub 2} NPs) affected the production of extracellular polymeric substances (EPSs), and thus might bring challenges for sludge pumping and mixing. In the present study, we investigated the rheological behavior of sludge before and after extraction of different EPSs fractions under various CeO{sub 2} NPs concentrations. It was found that the removal of loosely bound EPSs (LB-EPSs) could affect the shear stress (τ) and apparent viscosity (η), and the changes were dependent on CeO{sub 2} NPs concentrations. The removal of tightly bound EPSs (TB-EPSs) either with or without the addition of CeO{sub 2} NPs significantly decreased the yield stress (τ{sub y}) and the limiting viscosity (η{sub ∞}). Furthermore, the dynamic (strain, frequency and time) sweep measurements proved that the storage modulus (G') decreased after the extraction of TB-EPSs, indicating the weakened elastic and solid-like properties. The fluctuated content of polysaccharide in LB-EPSs and the increased amount of protein in TB-EPSs were likely to contribute to the variation of viscoelastic behaviors after the removal of LB-EPSs and TB-EPSs, respectively. In addition, the decreased rheological properties of sludge was also related to the increased zeta potential, decreased particle size and the removal of key organic matters of (10{sup 4}–10{sup 6} Da) with the extraction of stratified EPSs. These results were significant to take advantages of the rheological properties for sludge treatment in the presence of NPs.

54 ENVIRONMENTAL SCIENCES↗