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C, Volume 7, Issue 3 (September 2021) – 17 articles

Cover Story (view full-size image): Glucose is the basic constituent of biomass, and its valorisation is crucial to the circular economy. This study describes the preparation of nanosponges based on D-glucose and pyromellitic dianhydride and their use as precursors to obtain glassy carbons with a microporous texture (micropore size smaller than 10 Å) and relatively high surface area. These hard carbons can be easily obtained, with a yield of almost 30 wt% through a pyrolysis process performed at 800 °C in nitrogen atmosphere, and advantageously used to sequester relatively small molecules and contaminants. View this paper
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13 pages, 1495 KiB  
Article
Conformational Analysis of [60]PCBM from DFT Simulations of Electronic Energies, Bond Strain and the 13C NMR Spectrum: Input Geometry Determination and Ester Bond Rotation Dynamics
by Tong Liu and T. John S. Dennis
C 2021, 7(3), 66; https://doi.org/10.3390/c7030066 - 21 Sep 2021
Cited by 3 | Viewed by 2854
Abstract
With the aim of determining the best input geometry for DFT calculations of [60]PCBM, the geometry of 24 chemically possible [60]PCBM conformers were optimised and their electronic energies and average bond strains were determined. A DFT analysis of the relevant dihedral angles provided [...] Read more.
With the aim of determining the best input geometry for DFT calculations of [60]PCBM, the geometry of 24 chemically possible [60]PCBM conformers were optimised and their electronic energies and average bond strains were determined. A DFT analysis of the relevant dihedral angles provided insights into the dynamical behaviour of the ester group through sterically restricted bond rotations. In addition, the 13C NMR spectra of the six better performing conformers were simulated and compared with an experiment. There is a close correlation between average bond strain, total electronic energy and mean absolute error of the simulated 13C NMR spectra of the ester carbons. The best overall candidate conformer for the input geometry had the C61-C4, C4-C3 and C3-C2 single bonds of the alkyl chain in syn, anti and anti arrangements, respectively, and had the C2-C1 and C1-O single bonds of the ester in syn and anti arrangements, respectively. This contrasts strikingly with most representations of PCBM in the literature, which depict all relevant bonds in anti arrangements. Full article
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28 pages, 7173 KiB  
Review
Graphene-Enhanced Battery Components in Rechargeable Lithium-Ion and Lithium Metal Batteries
by Hao-Hsun Chang, Tseng-Hsiang Ho and Yu-Sheng Su
C 2021, 7(3), 65; https://doi.org/10.3390/c7030065 - 16 Sep 2021
Cited by 13 | Viewed by 9788
Abstract
Stepping into the 21st century, “graphene fever” swept the world due to the discovery of graphene, made of single-layer carbon atoms with a hexagonal lattice. This wonder material displays impressive material properties, such as its electrical conductivity, thermal conductivity, and mechanical strength, and [...] Read more.
Stepping into the 21st century, “graphene fever” swept the world due to the discovery of graphene, made of single-layer carbon atoms with a hexagonal lattice. This wonder material displays impressive material properties, such as its electrical conductivity, thermal conductivity, and mechanical strength, and it also possesses unique optical and magnetic properties. Many researchers see graphene as a game changer for boosting the performance of various applications. Emerging consumer electronics and electric vehicle technologies require advanced battery systems to enhance their portability and driving range, respectively. Therefore, graphene seems to be a great candidate material for application in high-energy-density/high-power-density batteries. The “graphene battery”, combining two Nobel Prize-winning concepts, is also frequently mentioned in the news and articles all over the world. This review paper introduces how graphene can be adopted in Li-ion/Li metal battery components, the designs of graphene-enhanced battery materials, and the role of graphene in different battery applications. Full article
(This article belongs to the Special Issue Batteries: The New Frontier for Carbon Materials)
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20 pages, 67844 KiB  
Article
Thermal and Principal Ablation Properties of Carbon-Fibre-Reinforced Polymers with Out-of-Plane Fibre Orientation
by Sebastian Eibl and Thomas J. Schuster
C 2021, 7(3), 64; https://doi.org/10.3390/c7030064 - 21 Aug 2021
Viewed by 2710
Abstract
This work characterises thermal properties of a typical epoxy-based carbon-fibre-reinforced polymer used in aircraft construction, but with an out-of-plane fibre orientation, and assesses its potential as a structural ablative material. Samples of the commercially available Hexply® 8552/IM7 are prepared with out-of-plane angles [...] Read more.
This work characterises thermal properties of a typical epoxy-based carbon-fibre-reinforced polymer used in aircraft construction, but with an out-of-plane fibre orientation, and assesses its potential as a structural ablative material. Samples of the commercially available Hexply® 8552/IM7 are prepared with out-of-plane angles up to 90°, with a focus on 0° to 15°, enhancing thermal conductivity through the thickness of the panel. Ablation processes are simulated by a hot-air blower at 580 °C, and examined in detail by ultrasonic testing and microfocused computed X-ray tomography afterwards. Matrix degradation is characterised by infrared spectroscopy and mass loss. To assess structural properties, tensile, compression, and bending tests are performed. The results show a loss in mechanical performance with an increasing fibre angle, which may be negligible for angles lower than ~5° in the initial state. Composite material with an out-of-plane fibre orientation is deeply penetrated concerning matrix degradation by thermal loading, but it is held together by the fibres fixed in the intact matrix underneath. This type of material shows a high potential for structural components in single-use, high-temperature, ablative applications with a focus on saving weight. Full article
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13 pages, 1756 KiB  
Article
2013–2014 Survey of Chars Using Raman Spectroscopy
by John McDonald-Wharry
C 2021, 7(3), 63; https://doi.org/10.3390/c7030063 - 19 Aug 2021
Cited by 3 | Viewed by 2696
Abstract
In late 2013, an open call for charcoal and biochar samples was distributed in an effort to compare a wide range of char samples by Raman spectroscopy. The samples contributed to this survey included: laboratory produced biochars, recent biochars produced in field conditions, [...] Read more.
In late 2013, an open call for charcoal and biochar samples was distributed in an effort to compare a wide range of char samples by Raman spectroscopy. The samples contributed to this survey included: laboratory produced biochars, recent biochars produced in field conditions, and ancient char samples previously analysed by carbon dating. By using selected Raman measurements, the char samples could be ranked in terms of the degree of thermochemical alteration or extent of carbon nanostructural development. The Raman results for recently produced biomass chars were generally consistent with the conversion of amorphous carbon formed at lower temperatures into condensed, polyaromatic, and graphene-like carbon formed at higher temperatures. A number of parameters calculated from the Raman spectra could be used to estimate the effective heat treatment temperatures in the recently produced biochars. Other samples such as anthracite coal, tire pyrolysis carbon, and ancient chars departed from the trends observed in the recently produced biomass chars using this approach. In total, 45 samples were analysed by Raman spectroscopy for this survey. Ancient and buried char samples displayed higher intensities for features in the Raman spectra associated with amorphous carbon. Full article
(This article belongs to the Section Carbon Materials and Carbon Allotropes)
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14 pages, 5330 KiB  
Article
Asymmetric Fiber Supercapacitors Based on a FeC2O4/FeOOH-CNT Hybrid Material
by Paa Kwasi Adusei, Kevin Johnson, Sathya N. Kanakaraj, Guangqi Zhang, Yanbo Fang, Yu-Yun Hsieh, Mahnoosh Khosravifar, Seyram Gbordzoe, Matthew Nichols and Vesselin Shanov
C 2021, 7(3), 62; https://doi.org/10.3390/c7030062 - 14 Aug 2021
Cited by 8 | Viewed by 2770
Abstract
The development of new flexible and lightweight electronics has increased the demand for compatible energy storage devices to power them. Carbon nanotube (CNT) fibers have long been known for their ability to be assembled into yarns, offering their integration into electronic devices. They [...] Read more.
The development of new flexible and lightweight electronics has increased the demand for compatible energy storage devices to power them. Carbon nanotube (CNT) fibers have long been known for their ability to be assembled into yarns, offering their integration into electronic devices. They are hindered, however, by their low intrinsic energy storage properties. Herein, we report a novel composite yarn, synthesized through solvothermal processes, that attained energy densities in the range between 0.17 µWh/cm2 and 3.06 µWh/cm2, and power densities between 0.26 mW/cm2 and 0.97 mW/cm2, when assembled in a supercapacitor with a PVDF-EMIMBF4 electrolyte. The created unique composition of iron oxalate + iron hydroxide + CNT as an anode worked well in synergy with the much-studied PANI + CNT cathode, resulting in a highly stable yarn energy storage device that maintained 96.76% of its energy density after 4000 cycles. This device showed no observable change in performance under stress/bend tests which makes it a viable candidate for powering wearable electronics. Full article
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34 pages, 7568 KiB  
Article
Applicability and Limitations of Simplified Elastic Shell Theories for Vibration Modelling of Double-Walled Carbon Nanotubes
by Matteo Strozzi, Oleg V. Gendelman, Isaac E. Elishakoff and Francesco Pellicano
C 2021, 7(3), 61; https://doi.org/10.3390/c7030061 - 9 Aug 2021
Cited by 4 | Viewed by 2692
Abstract
The applicability and limitations of simplified models of thin elastic circular cylindrical shells for linear vibrations of double-walled carbon nanotubes (DWCNTs) are considered. The simplified models, which are based on the assumptions of membrane and moment approximate thin-shell theories, are compared with the [...] Read more.
The applicability and limitations of simplified models of thin elastic circular cylindrical shells for linear vibrations of double-walled carbon nanotubes (DWCNTs) are considered. The simplified models, which are based on the assumptions of membrane and moment approximate thin-shell theories, are compared with the extended Sanders–Koiter shell theory. Actual discrete DWCNTs are modelled by means of couples of concentric equivalent continuous thin, circular cylindrical shells. Van der Waals interaction forces between the layers are taken into account by adopting He’s model. Simply supported and free–free boundary conditions are applied. The Rayleigh–Ritz method is considered to obtain approximate natural frequencies and mode shapes. Different aspect and thickness ratios, and numbers of waves along longitudinal and circumferential directions, are analysed. In the cases of axisymmetric and beam-like modes, it is proven that membrane shell theory, differently from moment shell theory, provides results with excellent agreement with the extended Sanders–Koiter shell theory. On the other hand, in the case of shell-like modes, it is found that both membrane and moment shell theories provide results reporting acceptable agreement with the extended Sanders–Koiter shell theory only for very limited ranges of geometries and wavenumbers. Conversely, for shell-like modes it is found that a newly developed, simplified shell model, based on the combination of membrane and semi-moment theories, provides results in satisfactory agreement with the extended Sanders–Koiter shell theory in all ranges. Full article
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14 pages, 4105 KiB  
Article
Monitoring of Curing and Cyclic Thermoresistive Response Using Monofilament Carbon Nanotube Yarn Silicone Composites
by Tannaz Tayyarian, Omar Rodríguez-Uicab and Jandro L. Abot
C 2021, 7(3), 60; https://doi.org/10.3390/c7030060 - 4 Aug 2021
Cited by 2 | Viewed by 2247
Abstract
The curing process and thermoresistive response of a single carbon nanotube yarn (CNTY) embedded in a room temperature vulcanizing (RTV) silicone forming a CNTY monofilament composite were investigated toward potential applications in integrated curing monitoring and temperature sensing. Two RTV silicones of different [...] Read more.
The curing process and thermoresistive response of a single carbon nanotube yarn (CNTY) embedded in a room temperature vulcanizing (RTV) silicone forming a CNTY monofilament composite were investigated toward potential applications in integrated curing monitoring and temperature sensing. Two RTV silicones of different crosslinking mechanisms, SR1 and SR2 (tin- and platinum-cured, respectively), were used to investigate their curing kinetics using the electrical response of the CNTY. It is shown that the relative electrical resistance change of CNTY/SR1 and CNTY/SR2 monofilament composites increased by 3.8% and 3.3%, respectively, after completion of the curing process. The thermoresistive characterization of the CNTY monofilament composites was conducted during heating–cooling ramps ranging from room temperature (RT~25 °C) to 100 °C. The thermoresistive response was nearly linear with a negative temperature coefficient of resistance (TCR) at heating and cooling sections for both CNTY/SR1 and CNTY/SR2 monofilament composites. The average TCR value was −8.36 × 10−4 °C−1 for CNTY/SR1 and −7.26 × 10−4 °C−1 for CNTY/SR2. Both monofilament composites showed a negligible negative residual relative electrical resistance change with average values of ~−0.11% for CNTY/SR1 and ~−0.16% for CNTY/SR2 after each cycle. The hysteresis amounted to ~21.85% in CNTY/SR1 and ~29.80% in CNTY/SR2 after each cycle. In addition, the effect of heating rate on the thermoresistive sensitivity of CNTY monofilament composites was investigated and it was shown that it reduces as the heating rate increases. Full article
(This article belongs to the Collection Feature Papers in the Science and Engineering of Carbons)
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14 pages, 3330 KiB  
Article
The Growth Behavior of Amorphous Hydrogenated Carbon a-C:H Layers on Industrial Polycarbonates—A Weak Interlayer and a Distinct Dehydrogenation Zone
by Torben Schlebrowski, Melanie Fritz, Lucas Beucher, Yongxin Wang, Stefan Wehner and Christian B. Fischer
C 2021, 7(3), 59; https://doi.org/10.3390/c7030059 - 29 Jul 2021
Cited by 2 | Viewed by 2559
Abstract
Polycarbonate (PC) is a material that is used in many areas: automotive, aerospace engineering and data storage industries. Its hardness is of particular importance, but some applications are affected by its low wettability or scratch susceptibility. This can be changed either by blending [...] Read more.
Polycarbonate (PC) is a material that is used in many areas: automotive, aerospace engineering and data storage industries. Its hardness is of particular importance, but some applications are affected by its low wettability or scratch susceptibility. This can be changed either by blending with other polymers, or by surface modifications, such as the application of an amorphous hydrogenated carbon layer (a-C:H). In this study, individual a-C:H layers of different thicknesses (10–2000 nm) were deposited on PC by RF PECVD. Both the layer morphology with AFM and SEM and the bonding states of the carbon on the surface with synchrotron-assisted XPS and NEXAFS were studied. The aim was to investigate the coatability of PC and the stability of the a-C:H. Special attention was paid to the interlayer region from 0 to 100 nm, since this is responsible for the layer to base material bonding, and to the zone of dehydrogenation (from about 1000 nm), since this changes the surface composition considerably. For PC, the interlayer was relatively small with a thickness of only 20 nm. Additionally, a correlation was found between the evolving grain structure and the development of the C‒H peak according to NEXAFS C K-edge measurements. Full article
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18 pages, 1540 KiB  
Review
Review of Cryogenic Carbon Capture Innovations and Their Potential Applications
by Carolina Font-Palma, David Cann and Chinonyelum Udemu
C 2021, 7(3), 58; https://doi.org/10.3390/c7030058 - 29 Jul 2021
Cited by 61 | Viewed by 20783
Abstract
Our ever-increasing interest in economic growth is leading the way to the decline of natural resources, the detriment of air quality, and is fostering climate change. One potential solution to reduce carbon dioxide emissions from industrial emitters is the exploitation of carbon capture [...] Read more.
Our ever-increasing interest in economic growth is leading the way to the decline of natural resources, the detriment of air quality, and is fostering climate change. One potential solution to reduce carbon dioxide emissions from industrial emitters is the exploitation of carbon capture and storage (CCS). Among the various CO2 separation technologies, cryogenic carbon capture (CCC) could emerge by offering high CO2 recovery rates and purity levels. This review covers the different CCC methods that are being developed, their benefits, and the current challenges deterring their commercialisation. It also offers an appraisal for selected feasible small- and large-scale CCC applications, including blue hydrogen production and direct air capture. This work considers their technological readiness for CCC deployment and acknowledges competing technologies and ends by providing some insights into future directions related to the R&D for CCC systems. Full article
(This article belongs to the Special Issue Carbon Materials for Physical and Chemical Hydrogen Storage)
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9 pages, 4712 KiB  
Article
Ab Initio Study of Porous Graphene–CNT Silicon Composite for Li-Ion and Na-Ion Batteries
by Dmitry A. Kolosov and Olga E. Glukhova
C 2021, 7(3), 57; https://doi.org/10.3390/c7030057 - 29 Jul 2021
Cited by 1 | Viewed by 2978
Abstract
In this work, we investigated composite materials based on graphene and carbon nanotubes with a silicon cluster from the standpoint of using them as Li-ion battery (LIB) and Na-ion battery (NIB) anodes. For our study, we used the density functional theory method, taking [...] Read more.
In this work, we investigated composite materials based on graphene and carbon nanotubes with a silicon cluster from the standpoint of using them as Li-ion battery (LIB) and Na-ion battery (NIB) anodes. For our study, we used the density functional theory method, taking into account the van der Waals interaction. The cavities of the composite were filled with lithium and sodium, and the energy characteristics of the structure were calculated through SIESTA molecular dynamics. The calculations showed the negative energy of adsorption for lithium and sodium and the negative value of the heat of formation of the composites. The introduction of a silicon cluster led to an increase in the specific capacity by 22.2% for the sodium and 37% for the lithium in comparison with the pure composite. The calculation of the transmission function showed a decrease in the resistance of the composite when a silicon cluster was added to the composite. We predict that the application of the considered composite will increase the efficiency of existing lithium-ion and sodium-ion batteries. Full article
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14 pages, 4891 KiB  
Article
Preparation and Carbonization of Glucose and Pyromellitic Dianhydride Crosslinked Polymers
by Fabrizio Caldera, Antonella Moramarco, Federico Cesano, Anastasia Anceschi, Alessandro Damin and Marco Zanetti
C 2021, 7(3), 56; https://doi.org/10.3390/c7030056 - 26 Jul 2021
Viewed by 3291
Abstract
In this work, four types of nanosponges were prepared from pyromellitic dianhydride (PMDA) and D-glucose (GLU) with different molar ratios (1.5:1, 2:1, 2.5:1 and 3:1). The obtained PMDA/GLU nanosponges were then pyrolyzed at 800 °C for 30 min under N2 gas flow. [...] Read more.
In this work, four types of nanosponges were prepared from pyromellitic dianhydride (PMDA) and D-glucose (GLU) with different molar ratios (1.5:1, 2:1, 2.5:1 and 3:1). The obtained PMDA/GLU nanosponges were then pyrolyzed at 800 °C for 30 min under N2 gas flow. The prepared polymeric nanosponges were investigated by FTIR spectroscopy, elemental and thermogravimetric analyses to unravel the role played by the different molar ratio of the precursors in the formation of the polymer. The pyrolyzed nanosponges were investigated by means of porosity measurements, X-ray diffraction analysis, Raman spectroscopy and high-resolution transmission electron microscopy. Notably, no significant correlation of the amounts of used precursors with the porous texture and structure was evidenced. The results corroborate that PMDA and GLU can be easily combined to prepare nanosponges and that the carbon materials produced by their pyrolysis can be associated with glassy carbons with a microporous texture and relatively high surface area. Such hard carbons can be easily obtained and shrewdly used to segregate relatively small molecules and organic contaminants; in this study methylene blue adsorption was investigated. Full article
(This article belongs to the Collection Feature Papers in the Science and Engineering of Carbons)
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14 pages, 3105 KiB  
Article
Biomass-Derived Carbons as Versatile Materials for Energy-Related Applications: Capacitive Properties vs. Oxygen Reduction Reaction Catalysis
by Stefan Breitenbach, Nemanja Gavrilov, Igor Pašti, Christoph Unterweger, Jiri Duchoslav, David Stifter, Achim Walter Hassel and Christian Fürst
C 2021, 7(3), 55; https://doi.org/10.3390/c7030055 - 24 Jul 2021
Cited by 9 | Viewed by 2692
Abstract
Biomass-derived carbons are very attractive materials due to the possibility of tuning their properties for different energy-related applications. Various pore sizes, conductivities and the inherent presence of heteroatoms make them attractive for different electrochemical reactions, including the implementation of electrochemical capacitors or fuel [...] Read more.
Biomass-derived carbons are very attractive materials due to the possibility of tuning their properties for different energy-related applications. Various pore sizes, conductivities and the inherent presence of heteroatoms make them attractive for different electrochemical reactions, including the implementation of electrochemical capacitors or fuel cell electrodes. This contribution demonstrates how different biomass-derived carbons prepared from the same precursor of viscose fibers can reach appreciable capacitances (up to 200 F g−1) or a high selectivity for the oxygen reduction reaction (ORR). We find that a highly specific surface area and a large mesopore volume dominate the capacitive response in both aqueous and non-aqueous electrolytic solutions. While the oxygen reduction reaction activity is not dominated by the same factors at low ORR overpotentials, these take the dominant role over surface chemistry at high ORR overpotentials. Due to the high selectivity of the O2 reduction to peroxide and the appreciable specific capacitances, it is suggested that activated carbon fibers derived from viscose fibers are an attractive and versatile material for electrochemical energy conversion applications. Full article
(This article belongs to the Special Issue Carbon Materials for Physical and Chemical Hydrogen Storage)
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16 pages, 3916 KiB  
Article
Facile Synthesis and Characterization of a Bromine-Substituted (Chloromethyl)Pyridine Precursor towards the Immobilization of Biomimetic Metal Ion Chelates on Functionalized Carbons
by Troy T. Handlovic, Tyler Moreira, Anoshia Khan, Haroon Saeed, Yousuf Khan, Mohammed R. Elshaer and Justin A. Bogart
C 2021, 7(3), 54; https://doi.org/10.3390/c7030054 - 23 Jul 2021
Cited by 2 | Viewed by 3412
Abstract
Multidentate ligands involving tethered pyridyl groups coordinated to transition metal ions have been frequently used to mimic the 3-histidine (3H), 2-histidine-1-carboxylate (2H1C) brace motifs or other combinations of histidine and carboxylate endogenous ligating residues found in bioinorganic metalloenzymes. It is of interest to [...] Read more.
Multidentate ligands involving tethered pyridyl groups coordinated to transition metal ions have been frequently used to mimic the 3-histidine (3H), 2-histidine-1-carboxylate (2H1C) brace motifs or other combinations of histidine and carboxylate endogenous ligating residues found in bioinorganic metalloenzymes. It is of interest to immobilize these ligand chelates onto heterogeneous supports. This, however, requires the use of bromine-substituted (chloromethyl)pyridines, whose current synthetic routes involve the use of extremely pyrophoric chemicals, such as n-butyllithium that require cryogenic reaction conditions, and toxic chemicals, such as thionyl chloride, that are challenging to handle and require extensive hazard controls. Herein, we report alternative methodologies towards the syntheses of 2-bromo-6-hydroxymethylpyridine and 2-bromo-6-chloromethylpyridine from inexpensive commercially available 2,6-dibromopyridine using isopropylmagnesium chloride lithium chloride complex (Turbo Grignard) and cyanuric chloride which are easier to handle and require milder reaction conditions than the conventional reagents. Gas chromatography-mass spectrometry (GC-MS) methods were developed and simple 1H- and 13C- nuclear magnetic resonance (NMR) and Fourier-transform infrared (FT-IR) spectroscopies were also used to monitor the conversion of both reaction steps and showed that products could be obtained and isolated through simple workups without the presence of unreacted starting material or undesired overchlorinated 2-chloro-6-chloromethylpyridine side product. Full article
(This article belongs to the Section Carbon Skeleton)
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14 pages, 12683 KiB  
Article
Reduction of Device Operating Temperatures with Graphene-Filled Thermal Interface Materials
by Jacob S. Lewis
C 2021, 7(3), 53; https://doi.org/10.3390/c7030053 - 21 Jul 2021
Cited by 7 | Viewed by 3135
Abstract
The majority of research into few layer graphene (FLG) thermal interface materials (TIM) concerns the direct quantification of innate composite properties with much less direct analysis of these materials in realistic applications. In this study, equilibrium temperatures of engineered device substitutes fixed to [...] Read more.
The majority of research into few layer graphene (FLG) thermal interface materials (TIM) concerns the direct quantification of innate composite properties with much less direct analysis of these materials in realistic applications. In this study, equilibrium temperatures of engineered device substitutes fixed to passive heat sink solutions with varying FLG concentration TIMs are experimentally measured at varying heat dissipation rates. A custom, precisely-controlled heat source’s temperature is continually measured to determine equilibrium temperature at a particular heat dissipation. It is found that altering the used FLG TIM concentrations from 0 vol.% to as little as 7.3 vol.% resulted in a decrease of combined TIM and passively-cooled heat sink thermal resistance from 4.23C/W to 2.93C/W, amounting to a reduction in operating temperature of ≈108C down to ≈85C at a heat dissipation rate of 20 W. The results confirm FLG TIMs’ promising use in the application of device heat dissipation in a novel, controllable experimental technique. Full article
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23 pages, 8516 KiB  
Article
Fused Filament Fabrication Three-Dimensional Printing Multi-Functional of Polylactic Acid/Carbon Black Nanocomposites
by Nectarios Vidakis, Markos Petousis, Emmanuel Velidakis, Nikolaos Mountakis, Peder Erik Fischer-Griffiths, Sotirios Grammatikos and Lazaros Tzounis
C 2021, 7(3), 52; https://doi.org/10.3390/c7030052 - 17 Jul 2021
Cited by 23 | Viewed by 4224
Abstract
Conductive Polymer Composites (CPCs) have recently gained an extensive scientific interest as feedstock materials in Fused Filament Fabrication (FFF) Three-dimensional (3D) printing. Polylactic Acid (PLA), widely used in FFF 3D printing, as well as its Carbon Black (CB) nanocomposites at different weight percentage [...] Read more.
Conductive Polymer Composites (CPCs) have recently gained an extensive scientific interest as feedstock materials in Fused Filament Fabrication (FFF) Three-dimensional (3D) printing. Polylactic Acid (PLA), widely used in FFF 3D printing, as well as its Carbon Black (CB) nanocomposites at different weight percentage (wt.%) filler loadings (0.5, 1.0, 2.5 and 5.0 wt.%), were prepared via a melt mixing filament extrusion process in this study and utilized to manufacture FFF 3D printed specimens. The nanocomposites were examined for their electrical conductivity. The highest loaded 3D printed CPC (5.0 wt.%) was tested as an electrothermal Joule heating device. Static tensile, flexural, Charpy’s impact and Vickers microhardness mechanical properties were investigated for the neat and PLA/CB 3D printed nanocomposites. Dynamic Mechanical Analysis (DMA) revealed a stiffening mechanism for the PLA/CB nanocomposites. Scanning Electron Microscopy (SEM) elucidated the samples’ internal and external microstructural characteristics. The PLA/CB 5.0 wt.% nanocomposite demonstrated also antibacterial properties, when examined with a screening process, against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). It can be envisaged that the 3D printed PLA/CB CPCs exhibited a multi-functional performance, and could open new avenues towards low-cost personalized biomedical objects with complex geometry, amongst others, i.e., surgery tools, splints, wearables, etc. Full article
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8 pages, 2435 KiB  
Article
Comments on the XPS Analysis of Carbon Materials
by David J. Morgan
C 2021, 7(3), 51; https://doi.org/10.3390/c7030051 - 6 Jul 2021
Cited by 139 | Viewed by 15147
Abstract
The surface chemistry of carbon materials is predominantly explored using x-ray photoelectron spectroscopy (XPS). However, many published papers have critical failures in the published analysis, stemming from an ill-informed approach to analyzing the spectroscopic data. Herein, a discussion on lineshapes and changes in [...] Read more.
The surface chemistry of carbon materials is predominantly explored using x-ray photoelectron spectroscopy (XPS). However, many published papers have critical failures in the published analysis, stemming from an ill-informed approach to analyzing the spectroscopic data. Herein, a discussion on lineshapes and changes in the spectral envelope of predominantly graphitic materials are explored, together with the use of the D-parameter, to ascertain graphitic content, using this information to highlight a simple and logical approach to strengthen confidence in the functionalization derived from the carbon core-level spectra. Full article
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16 pages, 1818 KiB  
Review
Carbons Formed in Methane Thermal and Thermocatalytic Decomposition Processes: Properties and Applications
by Emmi Välimäki, Lasse Yli-Varo, Henrik Romar and Ulla Lassi
C 2021, 7(3), 50; https://doi.org/10.3390/c7030050 - 25 Jun 2021
Cited by 8 | Viewed by 6161
Abstract
The hydrogen economy will play a key role in future energy systems. Several thermal and catalytic methods for hydrogen production have been presented. In this review, methane thermocatalytic and thermal decomposition into hydrogen gas and solid carbon are considered. These processes, known as [...] Read more.
The hydrogen economy will play a key role in future energy systems. Several thermal and catalytic methods for hydrogen production have been presented. In this review, methane thermocatalytic and thermal decomposition into hydrogen gas and solid carbon are considered. These processes, known as the thermal decomposition of methane (TDM) and thermocatalytic decomposition (TCD) of methane, respectively, appear to have the greatest potential for hydrogen production. In particular, the focus is on the different types and properties of carbons formed during the decomposition processes. The applications for carbons are also investigated. Full article
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