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Results for “Youngs Modulus”

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 433 records · Page 24
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Analysis of the Stable Interphase Responsible for the Excellent Electrochemical Performance of Graphite Electrodes in Sodium-Ion Batteries

Considerable efforts have been exerted to understand the formation and properties of the solid electrolyte interphase (SEI) in sodium ion batteries. However, the puzzling existence and role of SEI behind the huge volume changes of the graphite electrodes need to be answered. Herein, the reason of how ether-derived SEI maintains excellent reversibility despite the huge volume changes during cycling is unraveled. Theoretical simulations and Fourier-transform infrared spectroscopy demonstrate the formation mechanism of an SEI between the graphite anode and electrolyte. Furthermore, the high mechanical tolerance of the ether-derived SEI is confirmed in atomic force microscopy. A depth profile of X-ray photoelectron spectroscopy points to a multilayer structure of the ether-derived SEI. The outer layer comprises organics (sodium alkoxide), while the inorganics (Na 2 CO 3 , NaF) in interior region are mixed with some organics. Notably, the presence of organics ensures the adaptability of the SEI to the volume expansion of graphite during cycling, and the concentrated distribution of inorganics improves the Young's modulus (resistance to deformation). Therefore, the graphite anode exhibits high cycle stability (96.6% capacity retention ratio at 1 A g –1 over 860 cycles) and efficiency (≈99.5%).

25 ENERGY STORAGE↗
DOE OSTI2023

Probing the Mechanical Properties of 2D Materials via Atomic‐Force‐Microscopy‐Based Modulated Nanoindentation

Abstract As the field of low‐dimensional materials (1D or 2D) grows and more complex and intriguing structures are continuing to be found, there is an emerging need for techniques to characterize the nanoscale mechanical properties of all kinds of 1D/2D materials, in particular in their most practical state: sitting on an underlying substrate. While traditional nanoindentation techniques cannot accurately determine the transverse Young's modulus at the necessary scale without large indentations depths and effects to and from the substrate, herein an atomic‐force‐microscopy‐based modulated nanomechanical measurement technique with Angstrom‐level resolution (MoNI/ÅI) is presented. This technique enables non‐destructive measurements of the out‐of‐plane elasticity of ultra‐thin materials with resolution sufficient to eliminate any contributions from the substrate. This method is used to elucidate the multi‐layer stiffness dependence of graphene deposited via chemical vapor deposition and discover a peak transverse modulus in two‐layer graphene. While MoNI/ÅI has been used toward great findings in the recent past, here all aspects of the implementation of the technique as well as the unique challenges in performing measurements at such small resolutions are encompassed.

2D materials↗
DOE OSTI2022

Direct Ink Writing of 3D Zn Structures as High‐Capacity Anodes for Rechargeable Alkaline Batteries

The relationship between structure and performance in alkaline Zn batteries is undeniable, where anode utilization, dendrite formation, shape change, and passivation issues are all addressable through anode morphology. While tailoring 3D hosts can improve the electrode performance, these practices are inherently limited by scaffolds that increase the mass or volume. Herein, a direct write strategy for producing template‐free metallic 3D Zn electrode architectures is discussed. Concentrated inks are customized to build designs with low electrical resistivity (5 × 10 −4 Ω cm), submillimeter sizes (200 μm filaments), and high mechanical stability (Young's modulus of 0.1–0.5 GPa at relative densities of 0.28–0.46). A printed Zn lattice anode versus NiOOH cathode with an alkaline polymer gel electrolyte is then demonstrated. This Zn||NiOOH cell operates for over 650 cycles at high rates of 25 mA cm −2 with an average areal capacity of 11.89 mAh cm −2 , a cumulative capacity of 7.8 Ah cm −2 , and a volumetric capacity of 23.78 mAh cm −3 . A thicker Zn anode achieves an ultrahigh areal capacity of 85.45 mAh cm −2 and a volumetric capacity of 81.45 mAh cm −3 without significant microstructural changes after 50 cycles.

25 ENERGY STORAGE↗
DOE OSTI2026

DNA Crystals as a Template for Patterned Functional Materials

DNA nanotechnology offers a wide toolkit of molecular functionalities and scales, including intricate motifs less than 10 nm and periodic structures exceeding 100 µm. At larger scales, however, there are often significant tradeoffs for DNA structures, namely stability and mechanical strength. This work describes the design, synthesis, and characterization of a functionalized DNA crystal. Using a ligated DNA crystal grants significant freedom for various functional materials to be applied, in this case, semiconducting cadmium sulfide and palladium metal. Properties investigated in this study include stability, mechanical strength, and optoelectronic properties such as photoluminescence (PL) and electric conductivity. Significant changes are observed based on the functional material applied to DNA crystals. The Young's modulus of the crystal varies by about five orders of magnitude when functionalized with palladium. PL and semiconductive behaviors were observed when cadmium sulfide was attached. These crystals represent an expansion of the capabilities of DNA structures at these length scales, and additionally a platform for future studies exchanging the materials or altering the ligation scheme.

CdS↗
DOE OSTI2021

Computational study of the effect of core–skin structure on the mechanical properties of carbon nanofibers

The effect of the core–skin structure on the mechanical properties of carbon nanofibers is investigated in large-scale molecular dynamics simulations of tensile deformation of carbon nanofibers with the core–skin and homogeneous structures. Contrary to an established notion of the deleterious effect of the skin layer on the strength of carbon fibers, the presence of a high-quality skin layer is found to increase both the Young’s modulus and tensile strength of the nanofiber. A detailed analysis of the fracture process indicates that the nanofiber strengthening is related to the ability of skin layer to suppress crack nucleation at the core–skin interface. Furthermore, the computational predictions suggest that the design of new approaches to carbon fiber manufacturing and processing leading to the generation of a high-quality skin layer while avoiding the introduction of structural defects at the core–skin interface may yield a significant enhancement of the mechanical properties of carbon fibers.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Coal polymer composites prepared by fused deposition modeling (FDM) 3D printing

Coal is a vital energy resource worldwide, but pollutants and greenhouse gases from its combustion cause environmental problems. To explore the non-combustion approach to use and valorize coal, anthracite and lignite were blended with polyamide 12 (PA 12) through FDM printing in this work and compared in the composites. By adding lignite, Young’s modulus improved with increasing loading to 50 wt% while tensile strength leveled off among the composites, compared to that of PA 12. By contrast, the addition of anthracite decreased the tensile performance at all loadings. Rheology tests and morphology analyses suggested that the interactions between fillers (anthracite and lignite) and PA 12 may cause differences in tensile properties. In addition, the printed lignite composites showed improved thermal conductivity (~ twofold), indicating lignite demonstrates the potential to build functional composites. This work provides a strategy to use lignite in composites by 3D printing for value-added products and reduces the demand for petroleum-based polymers. Overall, our approach diverts lignite from combustion processes and alleviates the negative impact of lignite use on the environment.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Aluminum/SmCo 5 composites for structural and magnetic applications

Metal-bonded magnetic composites (MBMCs) present a promising alternative to dense sintered magnets, particularly for intricate components. Compared to polymer-based bonded magnets, MBMCs have wider applicability in harsh environments. In this paper, we demonstrate a solid-state shear-based manufacturing technique to introduce localized magnetization into a paramagnetic aluminum matrix by embedding SmCo5 permanent magnet particles. Our magnetic composites display hard magnetic behavior with a coercivity of 13 kOe and a remanent magnetization of 4.32 emu/g. In addition to magnetization, we also report a 9% improvement in Young’s modulus. Despite the local temperature rise during processing, the magnetic phases didn’t decompose into unwanted phases, preserving the composite's hard magnetic properties. Creation of an interfacial metallurgical bond with the matrix ensured the suitability of the composites for structural applications. Our study investigates the mechanical, and functional properties of composites, paving the way for lightweight structural magnetic composites with a transformative potential in the aerospace, nuclear, and automotive applications. This work underscores the potential for further optimization and development to drive innovations in magnet and equipment design.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Effect of the Incorporation of Lysozyme on the Properties of Jackfruit Starch Films

Jackfruit starch based biodegradable films containing lysozyme were characterized for their antimicrobial activity, thickness, solubility, water vapor permeability and mechanical properties. The biodegradable films had good appearance and antimicrobial activity against Micrococcus lysodeikticus. The thickness of the biodegradable films were not affected by the variation in pH, but the addition of lysozyme increased the thickness, the thickest films being those with the highest lysozyme concentrations. The variation in pH of the filmogenic solutions affected the solubility of the biodegradable films, water solubility being greatest at pH 7.0 and with the highest lysozyme concentration. The permeability of the biodegradable films was increased by incorporating lysozyme. The lysozyme concentration and pH variation caused changes in the mechanical properties. The addition of 8% lysozyme increased the tensile strength and Young’s modulus for all the pH values studied. With respect to the release of antimicrobial activity, the diffusion of lysozyme was shown to follow Fickian transport mechanism.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Investigation of Polypropylene-Montmorillonite Clay Nanocomposite Films Containing a Pro-degradant Additive

This paper investigates the performance of polypropylene (PP) incorporated with montmorillonite (MMT) nanoclay, maleic anhydride grafted PP (PP-g-MAH), and pro-degradant additive (TDPA®), which provides additional benefits of increasing biodegradability. A twin-screw extruder was used to compound PP, MMT, PP-g-MAH, and TDPA, and the extruded nanocomposite films were collected for testing, and their mechanical, thermal, barrier, oxo-biodegradability, and morphological properties were evaluated. Tensile test, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), oxygen permeability test, soil burial test, X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscope (SEM) analysis were used to investigate these properties. Increasing MMT content from 1 to 3 phr increases tensile strength and Young’s modulus of the neat PP samples up to ca.45% and 27% respectively. Improvement of thermal properties for neat PP samples was observed by increasing MMT content from 1 to 3 phr. However, at 4 phr MMT content, both mechanical and thermal properties of nanocomposites dropped slightly. For soil buried samples, DSC and TGA results revealed significant changes in the thermal properties for PP samples containing TDPE additive compared to neat PP, clearly confirming the effectiveness of this TDPA additive in promoting oxo-biodegradation process of PP. Similarly weight loss evaluation result shows that about 4% weight loss for sample (PP/TD), which is PP and TDPA blend only, compared to neat PP. However, increasing MMT content from 1 to 4 phr slightly reduced weight loss of PP from 3.5 to 1.5%, respectively, for 6 month soil exposure period, which indicates that increasing MMT content was detrimental to the degradation process. For higher MMT content, the oxygen permeability of PP nanocomposites was decreased by 46% of the corresponding values for neat PP. The XRD and TEM results confirmed the exfoliation structure of the nanocomposites. The morphological change after soil burial test was studied using scanning electron microscopy (SEM).

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2018

Novel Biocomposites Based on Sunflower Oil and Alfa Fibers as Renewable Resources

The aim of this work is to develop biocomposites based on modified sunflower oil as resin and short natural fibers from Alfa plants (Stipa tenacissima) as reinforcement. Epoxidized sunflower oil (ESFO) was chemically modified via acrylation reaction to obtain acrylated epoxidized sunflower oil resin (AESFO). The AESFO resin was then copolymerized with styrene as co-monomer in the presence of boron trifluoride (BF{sub 3}) as cationic initiator and cobalt octoate (Co) as catalyst. Experimental conditions of this modification were optimized by varying styrene, Co and BF{sub 3} wt%. The styrene was varied from 30, 40 to 50 wt% while the catalyst (Co) was varied from 0, 0.01, 0.02 to 0.03 wt%. Two different percents of BF{sub 3} were considered: 0.5 and 1 wt%. The prepared samples were evaluated according to their appearance and then characterized in terms of tensile properties (stress at break, Young’s modulus and elongation at break) to determine the best ratio of styrene/BF{sub 3}/Co. Alfa fibers, used as bio-reinforcement, were treated with a 5% NaOH solution and characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and thermo gravimetric analysis (TGA). Biocomposites were prepared by using untreated (UAF) and treated Alfa fibers (TAF) at a ratio of 5 wt% and characterized in terms of tensile properties and morphology by SEM. The best results were obtained with TAF. Then, the ratio of TAF was varied (5, 7.5 and 10 wt%) and the tensile and thermal properties of the biocomposites were characterized. The results showed that the best results were obtained with the ratio of 7.5 wt%.

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

Poly(lactic acid)/Cellulose Composites Obtained from Modified Cotton Fibers by Successive Acid Hydrolysis

This work is focused on the hydrolysis of cotton fibers from waste textiles to obtain micro and nanofibers to be used as reinforcements in polymer composites. To promote their compatibility with polymeric matrix, hydrolyzed cotton fibers were surface modified with various silane compounds. Thus, these fibers were mixed with commercial poly(lactic acid) (PLA) at 5% w/w loading by melt compounding. Acid treatments caused a decrease of the crystallinity index whereas the thermal stability was significantly improved, especially for cellulose fibers hydrolyzed in two steps. Morphological analysis revealed a reduction of the fibers diameter and a decrease of their length as a consequence of the hydrolysis. NMR analysis confirmed the silanization of the fibers by reaction with the silane agent. Tensile tests revealed that silanization treatments were able to increase the composite Young’s modulus and the stress at break with respect to the neat matrix, indicating that silanization improved the polymer/fiber compatibility interfacial adhesion. The overall results demonstrated that applying suitable surface modification strategies, waste cotton textiles can be effectively recycled as fillers in polymer based composites.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Preparation of nanofibrillated cellulose and application in reinforced PLA/starch nanocomposite film

Polylactic acid (PLA), one of the most promising biopolymers with exceptional properties, is being used in a wide variety of applications in diverse fields. However, low degradation rate, relatively high cost and inherently high brittleness of PLA severely hamper its further development, particularly in functional nanocomposites for bio-based packaging. In the present work, green, biodegradable and reinforced PLA-based nanocomposite films were designed and prepared, where starch was incorporated for reducing the overall cost of nanocomposites for large-scale application, and nanofibrillated cellulose (NFC) isolated from microcrystalline cellulose (MCC) via a completely green process was employed as a reinforcing phase. Initially, the morphology structure and dimension of the NFC samples isolated by high-pressure homogenization (HPH) coupled with hot water pretreatment were characterized using SEM, FT-IR, XRD, and laser scattering particle analyzer. Moreover, the effect of NFC loadings on the rheological behavior of the PLA based nanocomposite suspensions and the overall properties of the corresponding nanocomposite films were investigated. Results indicated that increased NFC loadings reduced the shear viscosity and shear stress of the nanocomposite suspensions. Furthermore, the desired PLA/starch/NFC nanocomposite films were found to exhibit improved tensile strength, Young’s modulus and reduced air permeability in comparison to pure PLA/starch films. This work offered an effective route for the preparation of biodegradable and reinforced PLA-based nanocomposite films, which may be promising bio-nanocomposite materials for food packaging applications.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2019

Effect of Rice Husk Derived Nanosilica on the Structure, Properties and Biodegradability of Corn-Starch/LDPE Composites

Development of material with enhanced mechanical properties and biodegradability by the incorporation of synthesized inorganic nanostructured mesoporous silica from rice husk has been investigated. The produced nanosilica (≈ 25 nm and 213.045 m{sup 2}/g surface area) and nanosilica blended LDPE/starch composites were extensively characterised by SEM, FTIR, XRD, XRF, TEM, EDAX and TGA analysis. The low cost of production estimated, ensures its feasibility toward large scale application. The addition of nanosilica into the matrix led to the enhancement of Young’s modulus and stiffness by a value of 535.6 MPa and 32172.81 N/m respectively at 3% nanosilica content, thereby enhancing the initial rigidity and resistivity towards deformation making a better biodegradable substitute in terms of initial application range. The MFI and hardness value also increased with increase of silica content upto 1.5% and 2% respectively to 7.23 g/10 min and 42 (Shor D). Increase in nanofiller content improved the value of degradation rate constant (k) of the weight loss data plot in both vegetable waste and garden soil environment. The addition of 1.5% of nanosilica to a blend of 80% LDPE and 20% starch showed almost the same biodegradation rate as that without nanosilica but with superior mechanical properties and applicability range.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2019

Effect of Talc on Mechanical Characteristics and Fracture Toughness of Poly(lactic acid)/Poly(butylene succinate) Blend

This research investigates the effect of talc additive on physical and mechanical characteristics of poly(lactic acid) (PLA) and poly(butylene succinate) (PBS) polymer blend. In the study, the talc content is varied between 0, 5, 10, and 20 parts per hundred resin (phr) and the PLA/PBS ratio is 80/20 w/w. The results reveal that talc enhances the mechanical properties of PLA/PBS blend. Specifically, tensile strength, Young’s modulus, and impact strength of PLA/PBS/talc composite increase as talc content rises. In addition, fracture toughness increases substantially as talc quantity is raised. The enhanced fracture toughness is attributable to nucleation of talc which promotes crystallization of PLA while hindering PBS crystal growth. Moreover, morphology analysis shows efficient distribution of talc in the polymer matrix.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Toward Greener Polymeric Blends: Study of PBAT/Thermoplastic Whey Protein Isolate/Beeswax Blends

This work evaluated the effects of partial substitution of PBAT by thermoplastic whey protein isolate (WPIT) with addition of beeswax through blends processing and their morphological, mechanical, structural, thermal and rheological properties. Whey protein isolate (WPI) was denatured at 90 °C, using glycerol as plasticizer, to be transformed in a thermoplastic material and subsequently blended with PBAT using a torque rheometer at 130 °C. Addition of 10 and 30% of WPIT in the PBAT matrix was investigated with and without beeswax. Blends were pressed as films with ~ 320 µm of thickness. Scanning electron microscopy (SEM) analysis of PBAT/WPIT blends films revealed the presence of domains. These domains are compounded of whey protein, while at the continuous phase a moderate degree of mixture between PBAT and WPIT was observed by Raman analyses. WPIT did not alter the degree of crystallinity and the glass-transition temperature (T{sub g}) of the PBAT in the blends. Thermogravimetric curves of the blends showed decomposition stages related to WPIT and PBAT phases. Thermal stability of blends decreased in comparison to WPIT, which was associated to the cleavage of disulfide bonds of WPIT during processing and causes other kind of interaction between components. Besides, blends containing WPIT remained non-rigid polymers with Young’s modulus below 70 MPa. The tensile strength and elongation at break decreased due the presence of WPIT. Beeswax did not influence the thermal and mechanical properties explored in this study.

36 MATERIALS SCIENCE↗
DOE OSTI2019

The Taste of Waste: The Edge of Eggshell Over Calcium Carbonate in Acrylonitrile Butadiene Rubber

Rubber technology experiences a new age by the use of biowaste or natural fillers. In this regard, taking properties of reinforcing agents from biowaste fillers remains as the challenging matter. Chicken eggshell (ES) biowaste has recently been introduced to substitute calcium carbonate (CaCO{sub 3}) duo to its superior properties and low price. In this work, composites based on acrylonitrile butadiene rubber (NBR) reinforced with ES and CaCO{sub 3} microfillers at various loading levels were prepared and characterized. To improve the interactions between fillers and the NBR matrix, ES and CaCO{sub 3} were surface-functionalized using a terpolymer, namely poly(vinyl 2-pyrrolidone-co-maleic acid-co-acrylic acid). Fourier-transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) were used to characterize the modified fillers. The incorporation of the functionalized fillers resulted in a significant rise in the maximum torque according to the rheometric measurements. The Young’s modulus of the ES-based and CaCO{sub 3}-based compounds showed a mild improvement over a wide range of filler contents. The elongation at break of the NBR composites, however, was dependent on the filler content. This work provides exciting opportunities for the design of novel and innovative coupling agents to be used in rubber applications.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Thermal, Rheological and Mechanical Properties of PETG/rPETG Blends

This paper presents the reuse process of post-consumer printed foils made of glycol-modified poly(ethylene terephthalate) (PETG). Fourier-transform infrared spectroscopy and a scanning electron microscope confirmed that these foils consist of PETG and PS layers. Firstly, foil pieces were immersed in the organic solution to remove all prints and after washing and drying they were extruded into regranulate rPETG pellets. Three types of PETG/rPETG blends were fabricated with the addition of 10, 20 and 30 wt% of virgin PETG. Microscopic analysis of the blends confirmed their homogeneity, as was also shown by the fact that there was only one glass transition peak in the heating curve given by differential scanning calorimetry. Moreover, in the presence of fresh PETG the degradation temperatures of rPETG improved significantly, and the viscosity of all blends was reduced as a result of shortened macromolecule chains in rPETG. Mechanical analysis of the materials showed that all blends have comparable tensile strength and a Young’s modulus that is higher than rPETG but lower than virgin PETG. Elongation at break decreases together with the content of rPETG.

36 MATERIALS SCIENCE↗
DOE OSTI2019

N-Silylated Benzothiazolium Dye as a Coupling Agent for Polylactic Acid/Date Palm Fiber Bio-composites

This work proposes a benzothiazole derivative bearing a silane moiety as a new coupling agent for polylactic acid (PLA) reinforced by date palm fibers (DPFs). The bio-composites are prepared by solution blending followed by melt compounding. From the samples produced, a complete characterization is performed including morphological, mechanical and thermal properties as a function of fiber content. The results show that the proposed fiber treatment is an easy and effective method to improve the interfacial properties and fiber dispersion leading to better material performance. For example, the addition of only 1 wt% of the dye–IPTMS to the bleached DPF not only improved the thermal stability of the biocomposites, but also led to a significant increase of the Young’s modulus at 7 wt% and higher torsion modulus up to 5 wt% (optimum value).

36 MATERIALS SCIENCE↗