Investigation of Carbon Nanotube Grafted Graphene Oxide Hybrid Aerogel for Polystyrene Composites with Reinforced Mechanical Performance

The rational design of carbon nanomaterials-reinforced polymer matrix composites based on the excellent properties of three-dimensional porous materials still remains a significant challenge. Herein, a novel approach is developed for preparing large-scale 3D carbon nanotubes (CNTs) and graphene oxide (GO) aerogel (GO-CNTA) by direct grafting of CNTs onto GO. Following this, styrene was backfilled into the prepared aerogel and polymerized in situ to form GO–CNTA/polystyrene (PS) nanocomposites. The results of X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy indicate the successful establishment of CNTs and GO-CNT and the excellent mechanical properties of the 3D frameworks using GO-CNT aerogel. The nanocomposite fabricated with around 1.0 wt% GO-CNT aerogel displayed excellent thermal conductivity of 0.127 W/m∙K and its mechanical properties were significantly enhanced compared with pristine PS, with its tensile, flexural, and compressive strengths increased by 9.01%, 46.8%, and 59.8%, respectively. This facile preparation method provides a new route for facilitating their large-scale production.

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A Facile Method for Batch Preparation of Electrochemically Reduced Graphene Oxide

Nanomaterials ◽

10.3390/nano9030376 ◽

2019 ◽

Vol 9 (3) ◽

pp. 376 ◽

Cited By ~ 6

Author(s):

Yi-Fang Hung ◽

Chia Cheng ◽

Chun-Kai Huang ◽

Chii-Rong Yang

Keyword(s):

Graphene Oxide ◽

Electrochemical Reduction ◽

Photoelectron Spectroscopy ◽

Large Scale ◽

Reduction Technique ◽

Chemical Agent ◽

Scale Production ◽

Large Scale Production ◽

Electrochemically Reduced Graphene Oxide ◽

Π Stacking Interaction

The electrochemical reduction of graphene oxide (GO) is an environmentally friendly and energy-saving method for improving the characteristics of GO. However, GO films must be coated on the cathode electrode in advance when usingthis technique. Thus, the formed electrochemically reduced GO (ERGO) films can be used only as sensing or conductive materials in devices because mass production of the flakes is not possible. Therefore, this study proposes a facile electrochemical reduction technique. In this technique, GO flakes can be directly used as reduced materials, and no GO films are required in advance. A 0.1 M phosphate buffered saline solution was used as the electrolyte, which is a highly safe chemical agent. Experimental results revealed that the as-prepared GO flakes were electrochemically reduced to form ERGO flakes by using a −10 V bias for 8 h. The ratio of the D-band and G-band feature peaks was increased from 0.86 to 1.12, as revealed by Raman spectroscopy, the π-π stacking interaction operating between the ERGO and GO has been revealed by UV-Vis absorption spectroscopy, and the C–O ratio was increased from 2.02 to 2.56, as indicated by X-ray photoelectron spectroscopy. The electrical conductivity of the ERGO film (3.83 × 10−1 S·cm−1) was considerably better than that of the GO film (7.92 × 10−4 S·cm−1). These results demonstrate that the proposed electrochemical reduction technique can provide high-quality ERGO flakes and that it has potential for large-scale production.

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Lemon Juice Assisted Green Synthesis of Reduced Graphene Oxide and Its Application for Adsorption of Methylene Blue

Technologies ◽

10.3390/technologies9040096 ◽

2021 ◽

Vol 9 (4) ◽

pp. 96

Author(s):

Md. Mahiuddin ◽

Bungo Ochiai

Keyword(s):

Methylene Blue ◽

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Large Scale ◽

Carbon Nanomaterials ◽

Cost Effective ◽

Lemon Juice ◽

Scale Production ◽

Reduced Graphene ◽

Microscopic Evaluation

Sustainable synthesis of reduced graphene oxide (rGO) is of crucial significance within the development of carbon nanomaterials. In this study, a green and eco-friendly strategy for the synthesis of rGO using lemon juice as the reducing agent for graphene oxide (GO) without using toxic and harmful chemicals was demonstrated. The reduction with lemon juice effectively eliminated the oxygen-containing functionalities of GO and regenerated the conjugated systems as confirmed by the UV-vis and FTIR spectroscopic and X-ray diffraction analyses. Microscopic evaluation showed the successful manufacturing of exfoliated and separated few layers of nano-sheets of rGO. The application of the resultant rGO as an adsorbent for organic pollutants was investigated using methylene blue (MB) as a model. The adsorption kinetics of MB on rGO is best matched with the pseudo-second-ordered kinetic model and the Langmuir model with a high adsorption capacity of 132.2 mg/g. The rGO exhibited good reusability with a removal efficiency of 80.4% in the fourth cycle. This green method provides a new prospect for the large-scale production of rGO in a cost-effective and safe manner.

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Synthesis and Characterization of Graphene Oxide/Chitosan Composite Aerogels with High Mechanical Performance

Polymers ◽

10.3390/polym11050777 ◽

2019 ◽

Vol 11 (5) ◽

pp. 777 ◽

Cited By ~ 7

Author(s):

Yang Gong ◽

Yingchun Yu ◽

Huixuan Kang ◽

Xiaohong Chen ◽

Hao Liu ◽

...

Keyword(s):

Mechanical Properties ◽

Graphene Oxide ◽

Photoelectron Spectroscopy ◽

Mechanical Performance ◽

X Ray Diffraction ◽

X Ray ◽

Composite Aerogels ◽

Mercury Porosimeter ◽

Chitosan Composite

Chitosan, a semi-crystalline biomolecule, has attracted wide attention due to its high synthesis flexibility. In this study, to improve the mechanical properties of chitosan aerogels (CSAs), graphene oxide (GO) was extracted and introduced into chitosan aerogels as fillers. The porous CSAs/GO composite aerogels were fabricated by an environmentally friendly freeze-drying process with different GO contents (0, 0.5, 1.0, 1.5, wt.%). The characteristics of the CSAs/GO were investigated by scanning electron microscopy (SEM), mechanical measurements and mercury porosimeter. The crystallinity of samples was characterized by X-ray diffraction (XRD). The mechanism of the effect of graphene oxide on chitosan was studied by Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The results show that the microstructure of the samples is developed in the network structure. The porosity of CSAs/GO aerogels is as high as 87.6%, and the tensile strength of the films increased from 6.60 MPa to 10.56 MPa with the recombination of graphene oxide. The crystallinity (CrI) of composite aerogels increased from 27% to 81%, which indicates that graphene oxide improves the mechanical properties of chitosan by chemical crosslinking.

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Process modeling, joint virtual testing and construction of joint connectors for mechanical fastening by flow-drilling screws

Proceedings of the Institution of Mechanical Engineers Part B Journal of Engineering Manufacture ◽

10.1177/0954405415577709 ◽

2015 ◽

Vol 231 (6) ◽

pp. 1048-1061 ◽

Cited By ~ 1

Author(s):

Mica Grujicic ◽

JS Snipes ◽

S Ramaswami

Keyword(s):

Mechanical Properties ◽

Finite Element ◽

Large Scale ◽

Mechanical Performance ◽

Constitutive Relations ◽

Computational Cost ◽

Three Dimensional ◽

Material Parameters ◽

Computational Analyses ◽

Flow Drilling

In this work, a computational approach is proposed in order to help establish the effect of various flow-drilling screw process and material parameters on the quality and the mechanical performance of the resulting flow-drilling screw joints. Toward that end, a sequence of three distinct computational analyses is developed. These analyses include the following: (a) finite element modeling and simulations of the flow-drilling screw process; (b) determination of the mechanical properties of the resulting flow-drilling screw joints through the use of three-dimensional, continuum finite element–based numerical simulations of various mechanical tests performed on the flow-drilling screw joints and (c) determination, parameterization and validation of the constitutive relations for the simplified flow-drilling screw connectors, using the results obtained in (b) and the available experimental results. The availability of such connectors is mandatory in large-scale computational analyses of whole-vehicle crash or even in simulations of vehicle component manufacturing, for example, car-body electro-coat paint-baking process. In such simulations, explicit three-dimensional representation of all flow-drilling screw joints is associated with a prohibitive computational cost. The approach developed in this work can be used, within an engineering-optimization procedure, to adjust the flow-drilling screw process and material parameters (design variables) in order to obtain a desired combination of the flow-drilling screw joint mechanical properties (objective function).

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Graphene Oxide Synthesis: Optimizing the Hummers and Marcano Methods

Nanoscience and Nanotechnology Letters ◽

10.1166/nnl.2020.3074 ◽

2020 ◽

Vol 12 (1) ◽

pp. 88-95

Author(s):

Majid S. Al-Ruqeishi ◽

Tariq Mohiuddin ◽

Moza Al-Moqbali ◽

Hamyar Al-Shukaili ◽

Said Al-Mamari ◽

...

Keyword(s):

Graphene Oxide ◽

Photoelectron Spectroscopy ◽

Large Scale ◽

Volume Ratio ◽

High Yield ◽

Scale Production ◽

Efficient Manner ◽

X Ray ◽

Hummers Method ◽

Number Of Layers

Fabricating graphene oxide (GO) in a cost-effective, efficient manner remains challenging. Some researchers manufacture GO that is comprised of a small number of layers by a modification of Hummers' method, as follows: (1) minimize use of NaNO3, a source of toxic gases; and (2) use MnO2 as the oxidizer. Other researchers fabricate GO by Marcano's method, where KMnO4 substitutes for MnO2. Here, one uses a 9:1 volume ratio of H2SO4/H3PO4. The role of KMnO4 is to diffuse slowly in the graphite interlayer and act as a peroxidation agent throughout the oxidation. For large-scale production, there is an explosion risk from using KMnO4 in H2SO4, and incomplete graphite oxidation. We overcame these challenges by growing GO sheets exhibiting an average size thickness of ∼3.1 ± 0.2 μm by optimizing the quantity of KMnO4 and H2SO4/H3PO4 as oxidizer ion sources, in modifications of both the Hummers and Marcano methods, without using NaNO3. Optimizing the reaction time and using small graphite flakes optimized oxidation to afford a high yield of GO sheets. X-ray diffraction showed an interlayer d-spacing of 5.7 Å for GO and 2.9 Å for the lesser quantity of remaining non-exfoliated graphite grains. Fourier-transform infrared spectroscopy showed no peaks for stretching vibrations within the graphitic domains, especially for GO grown via the modified Hummers method. Ultraviolet-visible and Raman spectroscopy showed that the number of layers with sp2 domains of interconnected carbon atoms, and disorder such as ripples and major defects at the edge planes, decreased compared to prior research. The Raman Id/Ig ratio of the GO sheets ranged from 1.21 to 1.75. The carbon/oxygen atomic ratio (RC/O), deduced from the C 1 s core level as per X-ray photoelectron spectroscopy, ranged from 0.43 to 6.84.

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Free-Standing Graphene Oxide and Carbon Nanotube Hybrid Papers with Enhanced Electrical and Mechanical Performance and Their Synergy in Polymer Laminates

International Journal of Molecular Sciences ◽

10.3390/ijms21228585 ◽

2020 ◽

Vol 21 (22) ◽

pp. 8585

Author(s):

Manoj Tripathi ◽

Luca Valentini ◽

Yuanyang Rong ◽

Silvia Bittolo Bon ◽

Maria F. Pantano ◽

...

Keyword(s):

Mechanical Properties ◽

Carbon Nanotubes ◽

Graphene Oxide ◽

Photoelectron Spectroscopy ◽

Mechanical Performance ◽

Hybrid Structure ◽

Free Standing ◽

Hybrid Filler ◽

X Ray ◽

The Individual

Hybrid nanomaterials fabricated by the heterogeneous integration of 1D (carbon nanotubes) and 2D (graphene oxide) nanomaterials showed synergy in electrical and mechanical properties. Here, we reported the infiltration of carboxylic functionalized single-walled carbon nanotubes (C-SWNT) into free-standing graphene oxide (GO) paper for better electrical and mechanical properties than native GO. The stacking arrangement of GO sheets and its alteration in the presence of C-SWNT were comprehensively explored through scanning electron microscopy, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction. The C-SWNTs bridges between different GO sheets produce a pathway for the flow of electrical charges and provide a tougher hybrid system. The nanoscopic surface potential map reveals a higher work function of the individual functionalised SWNTs than surrounded GO sheets showing efficient charge exchange. We observed the enhanced conductivity up to 50 times and capacitance up to 3.5 times of the hybrid structure than the GO-paper. The laminate of polystyrene composites provided higher elastic modulus and mechanical strength when hybrid paper is used, thus paving the way for the exploitation of hybrid filler formulation in designing polymer composites.

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A Review on Additive Manufacturing Possibilities for Electrical Machines

Energies ◽

10.3390/en14071940 ◽

2021 ◽

Vol 14 (7) ◽

pp. 1940

Author(s):

Muhammad Usman Naseer ◽

Ants Kallaste ◽

Bilal Asad ◽

Toomas Vaimann ◽

Anton Rassõlkin

Keyword(s):

Additive Manufacturing ◽

Large Scale ◽

Three Dimensional ◽

Electrical Machines ◽

Electromagnetic Properties ◽

Scale Production ◽

Performance Parameters ◽

Large Scale Production ◽

One Step ◽

Manufacturing Techniques

This paper presents current research trends and prospects of utilizing additive manufacturing (AM) techniques to manufacture electrical machines. Modern-day machine applications require extraordinary performance parameters such as high power-density, integrated functionalities, improved thermal, mechanical & electromagnetic properties. AM offers a higher degree of design flexibility to achieve these performance parameters, which is impossible to realize through conventional manufacturing techniques. AM has a lot to offer in every aspect of machine fabrication, such that from size/weight reduction to the realization of complex geometric designs. However, some practical limitations of existing AM techniques restrict their utilization in large scale production industry. The introduction of three-dimensional asymmetry in machine design is an aspect that can be exploited most with the prevalent level of research in AM. In order to take one step further towards the enablement of large-scale production of AM-built electrical machines, this paper also discusses some machine types which can best utilize existing developments in the field of AM.

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Effect of toughened polyamide-coated carbon fiber fabric on the mechanical performance and fracture toughness of CFRP

Journal of Composite Materials ◽

10.1177/0021998321999458 ◽

2021 ◽

pp. 002199832199945

Author(s):

Jong H Eun ◽

Bo K Choi ◽

Sun M Sung ◽

Min S Kim ◽

Joon S Lee

Keyword(s):

Mechanical Properties ◽

Fracture Toughness ◽

Photoelectron Spectroscopy ◽

Mechanical Performance ◽

Epoxy Composites ◽

Scanning Calorimetry ◽

Internal Damage ◽

Impact Tests ◽

Flexural Tests ◽

The Impact

In this study, carbon/epoxy composites were manufactured by coating with a polyamide at different weight percentages (5 wt.%, 10 wt.%, 15 wt.%, and 20 wt.%) to improve their impact resistance and fracture toughness. The chemical reaction between the polyamide and epoxy resin were examined by fourier transform infrared spectroscopy, differential scanning calorimetry and X-ray photoelectron spectroscopy. The mechanical properties and fracture toughness of the carbon/epoxy composites were analyzed. The mechanical properties of the carbon/epoxy composites, such as transverse flexural tests, longitudinal flexural tests, and impact tests, were investigated. After the impact tests, an ultrasonic C-scan was performed to reveal the internal damage area. The interlaminar fracture toughness of the carbon/epoxy composites was measured using a mode I test. The critical energy release rates were increased by 77% compared to the virgin carbon/epoxy composites. The surface morphology of the fractured surface was observed. The toughening mechanism of the carbon/epoxy composites was suggested based on the confirmed experimental data.

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Fabrication Techniques for Graphene Oxide-Based Molecular Separation Membranes: Towards Industrial Application

Nanomaterials ◽

10.3390/nano11030757 ◽

2021 ◽

Vol 11 (3) ◽

pp. 757

Author(s):

Ohchan Kwon ◽

Yunkyu Choi ◽

Eunji Choi ◽

Minsu Kim ◽

Yun Chul Woo ◽

...

Keyword(s):

Graphene Oxide ◽

Large Scale ◽

Spray Coating ◽

Dip Coating ◽

Small Scale ◽

Scale Production ◽

Separation Membranes ◽

Current Review ◽

Slot Die ◽

Continuous Fabrication

Graphene oxide (GO) has been a prized material for fabricating separation membranes due to its immense potential and unique chemistry. Despite the academic focus on GO, the adoption of GO membranes in industry remains elusive. One of the challenges at hand for commercializing GO membranes lies with large-scale production techniques. Fortunately, emerging studies have acknowledged this issue, where many have aimed to deliver insights into scalable approaches showing potential to be employed in the commercial domain. The current review highlights eight physical methods for GO membrane fabrication. Based on batch-unit or continuous fabrication, we have further classified the techniques into five small-scale (vacuum filtration, pressure-assisted filtration, spin coating, dip coating, drop-casting) and three large-scale (spray coating, bar/doctor blade coating, slot die coating) approaches. The continuous nature of the large-scale approach implies that the GO membranes prepared by this method are less restricted by the equipment’s dimensions but rather the availability of the material, whereas membranes yielded by small-scale methods are predominately limited by the size of the fabrication device. The current review aims to serve as an initial reference to provide a technical overview of preparing GO membranes. We further aim to shift the focus of the audience towards scalable processes and their prospect, which will facilitate the commercialization of GO membranes.

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