Academic literature on the topic 'Graphite oxide nanoplatelet'
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Journal articles on the topic "Graphite oxide nanoplatelet"
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Safie, Nur Ezyanie, and Mohd Asyadi Azam. "Understanding the structural properties of feasible chemically reduced graphene." AIMS Materials Science 9, no. 4 (2022): 617–27. http://dx.doi.org/10.3934/matersci.2022037.
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<abstract> <p>The production of pristine graphene materials for industrialization, often limited by the complicated synthesis route, has introduced other graphene derivatives with a workable and facile synthesis route, especially for mass production. For the chemical exfoliation process, the synthesis involves oxidants and reducing agents to exfoliate the graphene layer from the 3D graphite and remove excess oxygen-containing functional groups yielding graphene-like materials known as reduced graphene oxide (rGO). This work feasibly produces rGO with nanoplatelet morphology through the green solution-processable method. Upon reduction, the crystallite size for the a-axis (<italic>L<sub>a</sub></italic>) is more prominent (22.50 Å) than the crystallite size for the c-axis (<italic>L<sub>c</sub></italic>) (11.50 Å), suggesting the nanoplatelets structure of the end product, which is also confirmed by the morphology. The integrated intensity (<italic>I</italic><sub>D</sub>/<italic>I</italic><sub>G</sub>) ratio and average defect density (<italic>n<sub>D</sub></italic>) of as-prepared rGO confirmed the sp<sup>2</sup> restoration in the graphitic structure. Overall, the Raman and X-ray diffraction (XRD) characterization parameters validate the production of rGO nanoplatelets, especially with four graphene layers per domain, suggesting that high-quality rGO are achievable and ready to be implemented for the large-scale production.</p> </abstract>
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Cai, Dongyu, Kamal Yusoh, and Mo Song. "The mechanical properties and morphology of a graphite oxide nanoplatelet/polyurethane composite." Nanotechnology 20, no. 8 (February 3, 2009): 085712. http://dx.doi.org/10.1088/0957-4484/20/8/085712.
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Alateyah, A. I. "Thermal properties and morphology of polypropylene based on exfoliated graphite nanoplatelets/nanomagnesium oxide." Open Engineering 8, no. 1 (November 20, 2018): 432–39. http://dx.doi.org/10.1515/eng-2018-0052.
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Abstract Polypropylene/exfoliated graphite nanoplatelet (xGnP) composites reinforced with 2 wt.% nano-magnesia (n-MgO) have been successfully fabricated using an injection moulding machine. In the present study, the thermal properties and morphological structure of the composites were investigated. The XRD patterns of the composites showed xGnP and n-MgO peaks, and the intensity of the xGnP peaks increased with increased concentration in a polypropylene matrix. In addition, the SEM micrographs revealed a good dispersion of filler within the matrix. The nanocomposites showed better thermal stability than the pristine polymer. The improvement in onset temperature compared to virgin PP was found to be 3.6% for 100 wt.% PP, 4% for PP/1xGnP/2n-MgO, 5.5% for PP/2.5xGnP/2n-MgO, and 5.9% for PP/5xGnP/2n-MgO, PP/10xGnP/2n-MgO. In contrast, the crystallinity was reduced by the addition of fillers.
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da Luz, Fernanda Santos, Fabio da Costa Garcia Filho, Maria Teresa Gómez del-Río, Lucio Fabio Cassiano Nascimento, Wagner Anacleto Pinheiro, and Sergio Neves Monteiro. "Graphene-Incorporated Natural Fiber Polymer Composites: A First Overview." Polymers 12, no. 7 (July 18, 2020): 1601. http://dx.doi.org/10.3390/polym12071601.
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A novel class of graphene-based materials incorporated into natural lignocellulosic fiber (NLF) polymer composites is surging since 2011. The present overview is the first attempt to compile achievements regarding this novel class of composites both in terms of technical and scientific researches as well as development of innovative products. A brief description of the graphene nature and its recent isolation from graphite is initially presented together with the processing of its main derivatives. In particular, graphene-based materials, such as nanographene (NG), exfoliated graphene/graphite nanoplatelet (GNP), graphene oxide (GO) and reduced graphene oxide (rGO), as well as other carbon-based nanomaterials, such as carbon nanotube (CNT), are effectively being incorporated into NLF composites. Their disclosed superior mechanical, thermal, electrical, and ballistic properties are discussed in specific publications. Interfacial shear strength of 575 MPa and tensile strength of 379 MPa were attained in 1 wt % GO-jute fiber and 0.75 wt % jute fiber, respectively, epoxy composites. Moreover, a Young’s modulus of 44.4 GPa was reported for 0.75 wt % GO-jute fiber composite. An important point of interest concerning this incorporation is the fact that the amphiphilic character of graphene allows a better way to enhance the interfacial adhesion between hydrophilic NLF and hydrophobic polymer matrix. As indicated in this overview, two basic incorporation strategies have so far been adopted. In the first, NG, GNP, GO, rGO and CNT are used as hybrid filler together with NLF to reinforce polymer composites. The second one starts with GO or rGO as a coating to functionalize molecular bonding with NLF, which is then added into a polymeric matrix. Both strategies are contributing to develop innovative products for energy storage, drug release, biosensor, functional electronic clothes, medical implants, and armor for ballistic protection. As such, this first overview intends to provide a critical assessment of a surging class of composite materials and unveil successful development associated with graphene incorporated NLF polymer composites.
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Haridas, Haritha, and Marianna Kontopoulou. "Effect of specific surface area on the rheological properties of graphene nanoplatelet/poly(ethylene oxide) composites." Journal of Rheology 67, no. 3 (May 2023): 601–19. http://dx.doi.org/10.1122/8.0000531.
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The rheological properties of poly(ethylene oxide) containing graphene nanoplatelets (GNPs) having different specific surface areas (SSAs) are studied using steady shear and small amplitude oscillatory shear experiments. A series of GNPs having SSAs ranging from 175 ± 5 to 430 ± 13 m2/g was prepared using a thermomechanical exfoliation process. The complex viscosity, moduli, and yield stress of the composites increase with SSA, whereas electrical and rheological percolation threshold concentrations decrease, suggesting that higher SSAs promote filler network formation. Modeling of small amplitude oscillatory shear data using a two-phase model confirms that hydrodynamic effects dominate at low concentrations below 8 wt. %, where the particles are noninteracting. At higher concentrations, the response is dominated by filler-phase contributions. We demonstrate that the two-phase model parameters can be used to track the exfoliation of graphite into GNPs. Fitting of rheological percolation curves using Utracki and Lyngaae–Jørgensen models at low concentrations (noninteracting regime) resulted in aspect ratios between 19 and 76. At high concentrations (interacting particles), the aspect ratios determined by the Krieger–Daugherty model ranged between 5 and 24 due to aggregation. The highest aspect ratios (defined as the ratio of major dimension to minor dimension) were associated with GNPs that had the highest SSA of 430 m2/g. Strain sweeps revealed that the critical strain for the onset of nonlinear viscoelasticity scaled with SSA above the percolation threshold. The scaling relationships of the critical strain and storage modulus with volume fraction were used to infer the fractal dimensions of filler networks.
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Al Mahmud, Hashim, Matthew S. Radue, William A. Pisani, and Gregory M. Odegard. "Computational Modeling of Hybrid Carbon Fiber/Epoxy Composites Reinforced with Functionalized and Non-Functionalized Graphene Nanoplatelets." Nanomaterials 11, no. 11 (October 31, 2021): 2919. http://dx.doi.org/10.3390/nano11112919.
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The mechanical properties of aerospace carbon fiber/graphene nanoplatelet/epoxy hybrid composites reinforced with pristine graphene nanoplatelets (GNP), highly concentrated graphene oxide (GO), and Functionalized Graphene Oxide (FGO) are investigated in this study. By utilizing molecular dynamics data from the literature, the bulk-level mechanical properties of hybrid composites are predicted using micromechanics techniques for different graphene nanoplatelet types, nanoplatelet volume fractions, nanoplatelet aspect ratios, carbon fiber volume fractions, and laminate lay-ups (unidirectional, cross-ply, and angle-ply). For the unidirectional hybrid composites, the results indicate that the shear and transverse properties are significantly affected by the nanoplatelet type, loading and aspect ratio. For the cross-ply and angle ply hybrid laminates, the effect of the nanoplate’s parameters on the mechanical properties is minimal when using volume fractions and aspect ratios that are typically used experimentally. The results of this study can be used in the design of hybrid composites to tailor specific laminate properties by adjusting nanoplatelet parameters.
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Al Mahmud, Hashim, Matthew S. Radue, Sorayot Chinkanjanarot, and Gregory M. Odegard. "Multiscale Modeling of Epoxy-Based Nanocomposites Reinforced with Functionalized and Non-Functionalized Graphene Nanoplatelets." Polymers 13, no. 12 (June 13, 2021): 1958. http://dx.doi.org/10.3390/polym13121958.
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The impact on the mechanical properties of an epoxy resin reinforced with pristine graphene nanoplatelets (GNP), highly concentrated graphene oxide (GO), and functionalized graphene oxide (FGO) has been investigated in this study. Molecular dynamics (MD) using a reactive force field (ReaxFF) has been employed in predicting the effective mechanical properties of the interphase region of the three nanocomposite materials at the nanoscale level. A systematic computational approach to simulate the reinforcing nanoplatelets and probe their influence on the mechanical properties of the epoxy matrix is established. The modeling results indicate a significant degradation of the in-plane elastic Young’s (decreased by ~89%) and shear (decreased by ~72.5%) moduli of the nanocomposite when introducing large amounts of oxygen and functional groups to the robust sp2 structure of the GNP. However, the wrinkled morphology of GO and FGO improves the nanoplatelet-matrix interlocking mechanism, which produces a significant improvement in the out-of-plane shear modulus (increased by 2 orders of magnitudes). The influence of the nanoplatelet content and aspect ratio on the mechanical response of the nanocomposites has also been determined in this study. Generally, the predicted mechanical response of the bulk nanocomposite materials demonstrates an improvement with increasing nanoplatelet content and aspect ratio. The results show good agreement with experimental data available from the literature.
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Pajarito, Bryan, Amelia Jane Belarmino, Rizza Mae Calimbas, and Jillian Rae Gonzales. "Graphite Nanoplatelets from Waste Chicken Feathers." Materials 13, no. 9 (May 2, 2020): 2109. http://dx.doi.org/10.3390/ma13092109.
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Graphite nanoplatelets (GNPs), a functional 2D nanofiller for polymer nanocomposites, utilize natural graphite as a raw material due to its stacked graphene layers and outstanding material properties upon successful exfoliation into nano-thick sheets. However, the increasing demand for natural graphite in many industrial applications necessitates the use of graphite from waste resources. We synthesized GNPs from waste chicken feathers (WCFs) by graphitizing carbonized chicken feathers and exfoliating the graphitic carbon by high-speed homogenization and sonication. We then separated GNP from non-exfoliated carbon by centrifugation. This paper describes the morphology, chemical, and crystalline properties of WCF and its carbon derivatives, as well as the structural features of WCF-derived carbons. We obtained GNPs that have a 2D structure with huge variations in particle size and thickness. The GNP shows the presence of carbonyl groups, which are mostly attached at the edges of the stacked graphene sheets. Defects in the GNP are higher than in graphene synthesized from direct exfoliation of natural graphite but lower than in graphene oxide and reduced graphene oxide. To produce GNP of high quality from WCF, restacking of graphene sheets and concentration of carbonyls must be minimized.
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Elcioglu, Elif Begum. "A High-Accuracy Thermal Conductivity Model for Water-Based Graphene Nanoplatelet Nanofluids." Energies 14, no. 16 (August 21, 2021): 5178. http://dx.doi.org/10.3390/en14165178.
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High energetic efficiency is a major requirement in industrial processes. The poor thermal conductivity of conventional working fluids stands as a limitation for high thermal efficiency in thermal applications. Nanofluids tackle this limitation by their tunable and enhanced thermal conductivities compared to their base fluid counterparts. In particular, carbon-based nanoparticles (e.g., carbon nanotubes, graphene nanoplatelets, etc.) have attracted attention since they exhibit thermal conductivities much greater than those of metal-oxide and metallic nanoparticles. In this work, thermal conductivity data from the literature are processed by employing rigorous statistical methodology. A high-accuracy regression equation is developed for the prediction of thermal conductivity of graphene nanoplatelet-water nanofluids, based on the temperature (15–60 °C), nanoparticle weight fraction (0.025–0.1 wt.%), and graphene nanoparticle specific surface area (300–750 m2/g). The strength of the impact of these variables on the graphene nanoplatelet thermal conductivity data can be sorted from the highest to lowest as temperature, nanoparticle loading, and graphene nanoplatelet specific surface area. The model developed by multiple linear regression with three independent variables has a determination coefficient of 97.1% and exhibits convenience for its ease of use from the existing prediction equations with two independent variables.
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Pan, Shugang, Ning Zhang, and Yongsheng Fu. "Preparation of Nanoplatelet-Like MoS2/rGO Composite as High-Performance Anode Material for Lithium-Ion Batteries." Nano 14, no. 03 (March 2019): 1950033. http://dx.doi.org/10.1142/s1793292019500334.
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In this paper, we report a facile strategy to design and prepare reduced graphene oxide (rGO) supported MoS2 nanoplatelet (MoS2/rGO) via a solvothermal co-assembly process. It is found that in the as-obtained MoS2/rGO nanocomposite, MoS2 possesses unique platelet structure and rGO is exfoliated due to the in situ growth of MoS2 nanoplatelet, leading to a large specific surface area, facilitating rapid diffusion of lithium ions. The nanocomposite is used as a promising anode material for lithium-ion batteries and displays a high initial charge capacity (1382[Formula: see text]mA[Formula: see text]h[Formula: see text]g[Formula: see text]), excellent rate capability and cycling stability. The remarkable lithium storage performance of MoS2/rGO nanocomposite is mainly ascribed to the inherent nanostructure of the MoS2, and the synergistic effect between rGO nanosheets and MoS2 nanoplatelets.
Dissertations / Theses on the topic "Graphite oxide nanoplatelet"
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Liu, Kangsheng. "Stabilisation of non-equilibrium melt in a linear polyethylene in the presence of reduced graphene oxide nanoplatelets." Thesis, Loughborough University, 2015. https://dspace.lboro.ac.uk/2134/19853.
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In this thesis, investigation on stabilisation of non-equilibrium melt in the presence of high aspect ratio reduced graphene oxide nanosheets (rGON) was carried out. The non-equilibrium melt was prepared by melting disentangled ultrahigh molecular weight polyethylene (UHMWPE) which was synthesised using homogeneous single-site catalytic system. Rheological analyses of the disentangled UHMWPE/rGON nanocomposites prepared by physical mixing conclusively demonstrate the transformation of the melt from non-equilibrium state to equilibrium state was suppressed when the filler was added. The suppression effect on the transformation reached maximum at a certain filler content and the non-equilibrium melt state was retained within the experimental time, indicating the existence of strong filler-chain interaction that hindered the chain thermodynamics. In order to have better understanding of the suppression on the transformation, thermal analysis was performed on the non-equilibrium melts to follow the influence of non-equilibrium polymer melt on crystallisation kinetics of disentangled UHMWPE with and without rGON. The analysis was carried out by means of differential scanning calorimetry (DSC), and the changes in enthalpic relaxation process were found in good agreement with the rheological response of the melts. Thermal analysis showed the presence of two endothermic peaks in a sample of non-equilibrium melt that was left to crystallise under isothermal condition after melting. The high temperature endothermic peak (141.5 °C) was related to melting of crystals obtained on crystallisation from the disentangled domains of the heterogeneous (non-equilibrium) polymer melt, whereas the low melting temperature endothermic peak was related to melting of crystals formed from entangled domains of the melt. It was further found that with increasing the annealing time in melt (160 °C), the enthalpy of the lower melting temperature peak increased at the expense of the higher melting temperature peak, confirming transformation of the non-equilibrium polymer melt to equilibrium melt state. The enthalpic relaxation process as a function of rGON showed that at the specific content of the filler, where the suppression of the transformation reached maximum, the high endothermic peak remained independent of the annealing time of the polymer melt at 160 °C. This observation strengthened the concept that in the presence of the filler, chain dynamics was arrested to an extent that the everlasting non-equilibrium melt state having lower entanglement density was retained facilitating crystal formation having high melting endothermic temperature. This unique property of the nanocomposites provokes potential in facilitating their processability and making high demanding products in more complex dimensions.
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Danda, kranthi Chaitanya. "Processing-Structure-Property Relationships in Polymer Carbon Nanocomposites." Case Western Reserve University School of Graduate Studies / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=case156217449277816.
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Lee, Iping, and 李依平. "NO2 Gas Sensor Based on Polymer-exfoliated Graphene Nanoplatelets and Reduced Graphene Oxide." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/3q79e9.
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Bernardes, Adriana Filipe. "Liquid-phase exfoliation of highly oriented pyrolytic graphite and its oxidation by air-ozone atomization." Master's thesis, 2018. http://hdl.handle.net/10773/25595.
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In order to meet the demand for a highly profitable, versatile and
environmentally friendly graphene production method, Graphenest
developed a methodology based on liquid phase exfoliation that was
now tested using a different raw material: highly oriented pyrolytic
graphite (HOPG). After the exfoliation, the obtained multilayer
graphene dispersion underwent to a step of atomization using a
mixture of air-ozone, in order to achieve a material having a higher
oxidation level. To accomplish this, the exfoliation process was
carried out applying a Design of Experiments (DoE) that allowed to
understand the effect of four different variables on the yield of
graphene’s production: 1) temperature; 2) power density of
ultrasound equipment; 3) frequency of ultrasound equipment; and 4)
initial concentration of dispersed graphite.
All the samples were characterized by Raman spectroscopy and
Dynamic Light Scattering (DLS) in order to determine which
processual conditions allow the obtaining of graphene particles with
the smallest lateral size and thickness.
Additionally, the concentration of graphene dispersed obtained in
each of the exfoliation Runs was determined by UV-Vis
spectroscopy after a centrifugation step at different speeds (1000,
2000 and 4000 rpm). Before the atomization step, the samples with
the desired characteristics (smaller lateral size and thickness) were
characterized by transmission electron microscopy TEM.
Regarding the processual conditions, the DoE revealed that the
combination of the lowest level of each variable under analysis
allowed the production of more quantity (higher yield) and better
quality (smaller lateral size and thickness) of graphene particles.
The crystalline graphene samples showed ultrafine nature and good
flexibility.
In order to obtain a fast and efficient way for the functionalization of
this nanomaterial, the production of graphene oxide was tested
relying on the usage of an air-ozone gas mixture during the
atomization process. To verify the validity of the oxidation, a selected
sample was atomized exclusively with air and in paralell with a
mixture of air-ozone. These samples were then characterized by Xray
photoelectron spectroscopy (XPS) and the results, although to
some extent inconclusive, revealed a residual oxidation.Com vista a responder à procura de um método de produção de grafeno altamente rentável, versátil e amigo do ambiente, a Graphenest desenvolveu uma metodologia baseada numa exfolição em fase líquida que foi agora testada com recurso ao uso de uma matéria-prima diferente: grafite pirolitica altamente orientada (HOPG). Após a exfoliação, a dispersão de grafeno de multicamadas passou por uma etapa de atomização utilizando uma mistura de ar-ozono, por forma a se obter um material com um nível de oxidação superior. Para tal, o processo de exfoliação foi realizado, efetuando um desenho de experiências (DoE) que permitisse compreender o efeito de quatro variáveis distintas no rendimento da produção de grafeno: 1) temperatura; 2) densidade de potência do equipamento de ultrassons; 3) frequência do equipamento de ultrassons; e 4) concentração inicial de grafite dispersa. Todas as amostras foram caracterizadas por espectroscopia Raman e por Dispersão Dinâmica de Luz (DLS) com o objetivo de determinar as condições processuais que permitem a obtenção de particulas com tamanho lateral e espessura mais pequenas. Adicionalmente, a concentração de grafeno disperso após cada uma das corridas de exfoliação foi determinada por espectroscopia UVVis, após centrifugação com diferentes velocidades (1000, 2000 e 4000 rpm). Antes da etapa de atomização, as amostras com as caracteristicas pretendidas (menor dimensão lateral e espessura) foram caracterizadas por microscopia eletrónica de trasmissão (TEM). Relativamente às condições processuais, o DoE revelou que a combinação do nível mais baixo de cada variável em análise permitiu a produção de maior quantidade (maior rendimentos) e melhor qualidade (menor dimensão lateral e espessura) de partículas de grafeno. As amostras cristalinas de grafeno manifestaram natureza ultrafina e boa flexibilidade. De modo a se obter uma forma rápida e eficiente para a funcionalização deste nanomaterial, a produção de óxido de grafeno foi testada, recorrendo a uma mistura de gás ar-ozono durante o processo de atomização. Para avaliar a oxidação, uma determinada selecção de amostras foi atomizada com ar e paralelamente com uma mistura de ar-ozono. Essas amostras foram, de seguida, caracterizadas por espectroscopia de fotoeléctrones excitados por raios-X (XPS) e os resultados, embora, de certa forma, inconclusivos, revelaram uma oxidação residual.
Mestrado em Engenharia Química
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TSENG, CHIEN-CHENG, and 曾建誠. "Synthesis of functionalized graphene oxide and functionalized exfoliated graphene nanoplatelets and effects of nano-scale and submicron-scale core-shell rubber additives, inorganic silica /organic polymer core-shell particle, functionalized graphene oxide, and functionalized exfoliated graphene nanoplatelet on the volume shrinkage, mechanical properties and cured sample morphology for unsaturated polyester and vinyl ester resins." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/14841570663378769252.
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碩士國立臺灣科技大學
化學工程系
103
The effects of the submicron-scale core–shell rubber (CSR), nano-scale silane-grafted silica nanoparticles (SNP) and thermally reduced graphene oxide as special additives on volume shrinkage characteristics and mechanical properties of the styrene (St)/vinyl ester resin(VER)/special additive ternary systems cured at 120 ℃ and post cured at 150 ℃have been investigated. The SNP with a diameter of 15 nm was synthesized by size-controllable hydrolysis of elemental silicon, followed by the surface treatment of 3-methacryloxypropyltrimethoxysilane (γ-MPS) to obtain the MPS-silica. The CSRs were synthesized by two-stage soapless emulsion polymerizations, where the soft core was made from rubbery poly(n-butyl acrylate), and the hard shell was made from 85 mole% of methyl methacrylate, 15mol% glycidyl methacrylate, and 1mole% of ethylene glycol dimethacrylate as the crosslinking agent. The experimental results are explained by an integrated approach of measurements of the static phase characteristics of a St/VER/special additive system, the cured sample morphology with SEM, TEM, and mechanical properties.
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Dai, Shao-Hua, and 戴劭樺. "Effects of nano-scale and submicron-scale core-shell rubber additives,silane-grafted silica particle, functionalized graphene oxide, functionalized exfoliated graphene nanoplatelet, polymer-grafted graphene oxide, and polymer-grafted exfoliated graphene nanoplatelet on the cure kinetics, glass transition temperatures, and X-ray scattering characteristics for vinyl ester resins." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/35735797397712573425.
Full textAbstract:
碩士國立臺灣科技大學
化學工程系
103
The effects of four special additives, including (1) nano-scale and submicron-scale core-shell rubber additive (CSR), (2) silane-grafted silica noanoparticle (SNP), (3) functionalized graphene oxide (GO), and (4) functionalized thermally reduced graphene oxide (TRGO), on the cure kinetics, glass transition temperature and X-ray scattering characteristics for the Styrene(St)/Vinyl ester resin(VER)/special additives ternary systems after the cure have been investigated. The scattering intensity of vinyl ester resin (VER) with different structure in dilute styrene solution was measured by the method of small angle X-ray scattering (SAXS), and the radius of gyration of VER can then be calculated by using the Guinier law. Measuring the X-ray scattered intensity profile of the cured specimens for St/VER/GO (or TRGO) ternary system by using wide angle X-ray scattering (WAXS) allows one to investigate the change of d-spacing and the degree of dispersion of the substrate of functionalized graphene oxide (GO) or functionalized thermally reduced graphene oxide (TRGO) nanoplatelet. The structure of intercalated or exfoliated nanocomposites for the cured St/VER/GO (or TRGO) ternary system can then be identified. In the meanwhile, the chemical structures of functionalized graphene oxide (GO) and functionalized thermally reduced graphene (TRGO) were also characterized with Raman Spectroscope (RS) Moreover, the reaction kinetics for the St/VER/special additive ternary system during the cure was measured by differential scanning calorimetry (DSC) and fourier transform infrared spectroscopy (FTIR). Finally, based on the Takayanagi mechanical models, the glass transition temperature in each region of the cured samples for St/VER/special additive ternary system has been measured by dynamic mechanical analysis (DMA).
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FORTUNATO, MARCO. "Production and characterization of ZnO/Graphene devices for energy harvesting." Doctoral thesis, 2019. http://hdl.handle.net/11573/1237548.
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In this thesis, different types of innovative highly performing piezoelectric nanomaterials and nanocomposites have been synthesized and characterized for energy harvesting application. In order to evaluate the piezoelectric properties of the produced materials, a novel approach to quantitatively evaluate the effective piezoelectric coefficient d33, trough Piezoresponse Force Microscopy (PFM), has been developed. PFM is one of the most widely used techniques for the characterization of piezoelectric materials at nanoscale, since it enables the measurement of the piezo-displacement with picometer resolution. PFM is a non-invasive and easy to use test method; it requires only a bottom electrode (no need of a top-electrode deposition over the material under test), thus considerably simplifying the test structure preparation. In particular, in order to have a quantitative information on the d33 a calibration protocol was developed. To get a macroscale characterization of the piezoelectric coefficient, the PFM signal is averaged over different areas of the sample. The proposed method allows to precisely evaluate the piezoelectric coefficient enabling a proper comparison among the different materials analysed.
Two different classes of piezoelectric materials have been synthesized and characterized:
zinc oxide nanostructures, in particular zinc oxide nanorods (ZnO-NRs) and zinc oxide nanowalls (ZnO-NWs),
polyvinylidene fluoride (PVDF) nanocomposites films.
The produced piezoelectric materials were fabricated using process which are cost-effective, time-consuming and easy to scale-up. The ZnO nanostuctures were grown by chemical bath deposition (CBD), that guarantees high deposition rate on a wide variety of substrates. PVDF nanocomposite films were produced with a simple solution casting method, without the need of subsequent electrical poling step. To enhance the piezoelectric properties of PVDF films we investigated different PVDF nanocomposite films:
PVDF filled with Graphene nanoplatelets (GNPs) or with ZnO-NRs;
PVDF filled with different types of hexahydrate metal-salts (HMS);
PVDF filled with HMS in combination with nanofillers, like GNPs or ZnO-NRs.
We found that the piezoelectric coefficient of the ZnO-NRs is (7.01±0.33) pm/V and (2.63±0.49) pm/V for ZnO-NWs. The higher piezoelectric response of ZnO-NRs is believed to be due to a better crystallinity and a less defectiveness of the ZnO-NRs if compared to the ZnO-NWs, as it has been confirmed by X-ray diffraction (XRD) spectra and by photoluminescence spectroscopy (PL) measurements.
The neat PVDF show a d33 limited to 4.65 pm/V; when the nanofillers are added the d33 increases up to 6 pm/V. This value reaches 8.8 pm/V when a specific hexahydrate metal-salts: [Mg(NO3)2∙6H2O] is dispersed in the PVDF polymer matrix.
From the comparative analysis of the synthesized materials we found that the sample produced using the dissolution of HMS in PVDF shows the best piezoelectric response (8.8 pm/V) and the most attractive structural and mechanical properties to fabricate a flexible nanogenerators. Therefore, a porous piezoelectric HMS-PVDF nanocomposite film has been used as active material to fabricate flexible nanogenerator. To build such a device, graphene-gold flexible top electrodes were developed. The bilayer electrode structure avoids short circuits between top and bottom electrodes, observed in the absence of graphene interlayer. The nanogenerator was tested using a commercial mini-shaker and operated successfully. The piezoelectric coefficient determined from the electromechanical tests was 9.00 pm/V, which is in good agreement with the one (8.88±3.14) pm/V measured through PFM on the same PVDF film without top electrode. We also measured the piezoelectric coefficient of PVDF using PFM with and without top electrode and both values were found to be in close agreement. This finding suggests that the local characterization using PFM is also a good representation of the global piezoelectric properties of the samples.
The progress on advanced piezoelectric materials reported in this work opens new opportunities to fabricate energy harvesters and sensors for wearable and smart clothing applications.
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Huang, Hao-Kuan, and 黃豪寬. "Synthesis of nano-scale colloidal silica from elemental silicon by hydrolysis, and synthesis of polymer-grafted silica nanoparticle, polymer-grafted graphene oxide, and polymer-grafted exfoliated graphene nanoplatelet with core-shell structure as low-profile additives and tougheners for unsaturated polyester and vinyl ester resins by RAFT living free radical solution polymerizations." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/29945158148023952847.
Full textAbstract:
碩士國立臺灣科技大學
化學工程系
103
Synthesis of nano-scale inorganic/organic core-shell particle (CSP) as low-profile additives (LPA) and toughenors for thermoset resins, and their effects on the cured sample morphology, volume shrinkage characteristics and mechanical properties for low-shrink vinyl ester resins (VER) during the cure were investigated. These CSP designated as SiO2-polymer or GO-polymer, the former of which contained silica nanoparticle (SNP) as the core and the latter of which contained graphite oxide(GO) as the cure and both of them with organic polymer as the shell, were synthesized by the Z supported reversible addition-fragmentation chain transfer (RAFT) graft polymerization using silica-supported or graphite oxide-supported 3-(benzylsulfanylthiocarbonylsulf- anl) propionic acid (SiO2-BSPA or GO-BSPA) as the chain transfer agent (CTA). The silica nanoparticle with a diameter of 15 nm was synthesized by size-controllable hydrolysis of elemental silicon, and the graphite oxide(GO) was synthesized from natural graphites with average particle size of 2 to 15μm. The grafted polymer as the shell of the SiO2-polymer or GO-polymer was made from poly(methyl acrylate)(PMA), copolymer of MA and glycidyl methacrylate(poly(MA-co-GMA)),poly(butylacrylate)-block-poly(methyl acrylate) (PBA-b-PMA) or PBA-block-poly(MA-co-GMA). Structure characterizations of BSPA, SiO2-BSPA, SiO2-polymer, GO-BSPA and GO-polymer have been performed by using FTIR, 1H-NMR, 13C-NMR, GPC and DSC. In this work, the effects of SiO2-polymer and GO-polymer on the volume shrinkage characteristics and mechanical properties of the styrene(St)/ vinyl ester(VER)/ SiO2-polymer or (GO-polymer) ternary systems during the cure have also been explored.
Book chapters on the topic "Graphite oxide nanoplatelet"
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Vidakis, N., M. Petousis, E. Velidakis, and A. Maniadi. "Mechanical Properties of 3D-Printed ABS with Combinations of Two Fillers: Graphene Nanoplatelets, TiO2, ATO Nanocomposites, and Zinc Oxide Micro (ZnOm)." In Lecture Notes in Mechanical Engineering, 635–45. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-7787-8_51.
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Bhilkar, P. R. "Functionalized Carbon Nanomaterials: Fabrication, Properties, and Applications." In Emerging Nanomaterials and Their Impact on Society in the 21st Century, 72–99. Materials Research Forum LLC, 2023. http://dx.doi.org/10.21741/9781644902172-4.
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In recent times, carbon based nanomaterials (CNMs) like graphene, graphene oxide (GO), graphene nanoplatelet (GNP), carbon nanotubes (CNTs), carbon dots (CDs), and fullerenes are among the most promising nanomaterial due to their extraordinary physiochemical, electrical, optical, mechanical, and thermal behavior. CNMs have many potential applications, including energy storage and conversion, biomedical, catalysts, composites, and biomaterials. Nonetheless, many advanced applications require the proper functionalization of CNMs. This chapter analyses the routes for CNMs functionalization and their impact on their structure and properties. Furthermore, the current and potential application of functionalized CNMs are discussed, and the challenges and future research directions are highlighted.
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Chaudhuri, Biswadeep. "Biopolymers-graphene oxide nanoplatelets composites with enhanced conductivity and biocompatibility suitable for tissue engineering applications." In Fullerens, Graphenes and Nanotubes, 457–544. Elsevier, 2018. http://dx.doi.org/10.1016/b978-0-12-813691-1.00012-9.
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"The reinforcement effects of graphene oxide nanoplatelets on the mechanical and viscoelastic properties of natural rubber." In Constitutive Models for Rubber VIII, 571–76. CRC Press, 2013. http://dx.doi.org/10.1201/b14964-102.
Full textConference papers on the topic "Graphite oxide nanoplatelet"
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Hung, Ming-Tsung, Oyoung Choi, Zhanhu (John) Guo, H. Hahn, and Y. Ju. "Heat Transport in Graphite Nanoplatelet (GNP)-Reinforced Polymeric Nanocomposites and Aluminum Oxide Nanofluids." In 9th AIAA/ASME Joint Thermophysics and Heat Transfer Conference. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2006. http://dx.doi.org/10.2514/6.2006-3112.
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MAHMUD, HASHIM AL, ,. MATTHEW RADUE, WILLIAM PISANI, and GREGORY ODEGARD. "COMPUTATIONAL MODELING OF EPOXY-BASED HYBRID COMPOSITES REINFORCED WITH CARBON FIBERS AND FUNCTIONALIZED GRAPHENE NANOPLATELETS." In Thirty-sixth Technical Conference. Destech Publications, Inc., 2021. http://dx.doi.org/10.12783/asc36/35846.
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The impact on the mechanical properties of unidirectional carbon fiber (CF)/epoxy composites reinforced with pristine graphene nanoplatelets (GNP), highly concentrated graphene oxide (GO), and Functionalized Graphene Oxide (FGO) are investigated in this study. The localized reinforcing effect of each of the graphene nanoplatelet types on the epoxy matrix is predicted at the nanoscale-level by molecular dynamics. The bulk-level mechanical properties of unidirectional CF/epoxy hybrid composites are predicted using micromechanics techniques considering the reinforcing function, content, and aspect ratios for each of the graphene nanoplatelets. In addition, the effect of nanoplatelets dispersion level is also investigated for the pristine graphene nanoplatelets considering a lower dispersion level with four layers of graphene nanoplatelets (4GNP). The results indicate that the shear and transverse properties are significantly affected by the nanoplatelet type, loading and aspect ratio. The results of this study can be used in the design of hybrid composites to tailor specific laminate properties by adjusting nanoplatelet parameters.
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"Graphite Nanoplatelets and Graphene Oxide Influence on C-S-H Formation." In "SP-329: Superplasticizers and Other Chemical Admixtures in Concrete Proceedings Twelfth International Conference, Beijing, China". American Concrete Institute, 2018. http://dx.doi.org/10.14359/51711218.
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Mahanta, Nayandeep K., and Alexis R. Abramson. "Thermal conductivity of graphene and graphene oxide nanoplatelets." In 2012 13th IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm). IEEE, 2012. http://dx.doi.org/10.1109/itherm.2012.6231405.
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Sezer, Nurettin, Adnan Ali, Muataz A. Atieh, and Muammer Koc. "Synthesis and Characterization of Graphene/Zinc Oxide Nanocomposites." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-71291.
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This study investigates the synthesis and characterization of graphene/zinc oxide nanocomposites. Wet impregnation method was employed for the synthesis. Firstly, graphene nanoplatelets and zinc nitrate hexahydrate were concurrently dispersed in ethanol and subjected to sonication for 1 h. Then, the dispersion was put in a furnace at 70 °C overnight. The paste was then collected and heated further up to 400 °C in air for a duration of 4 h. The process was proceeded to yield insoluble nanocomposites. The synthesis was followed by characterization of the nanocomposite samples by Field Emission Scanning Electron Microscopy (FESEM), X-Ray Diffraction (XRD) and Thermal Gravimetric Analysis (TGA). The XRD pattern revealed the presence of ZnO crystals and graphene. The FESEM images showed that ZnO crystals with average particle size of 30 nm are uniformly distributed on graphene surfaces. According to the TGA result, the content of nanocomposites is in good agreement with the materials used during synthesis.
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ANURAKPARADORN, KANAT, ALAN TAUB, and ERIC MICHIELSSEN. "DISPERSION OF COBALT FERRITE FUNCTIONALIZED GRAPHENE NANOPLATELETS IN PLA FOR EMI SHIELDING APPLICATIONS." In Thirty-sixth Technical Conference. Destech Publications, Inc., 2021. http://dx.doi.org/10.12783/asc36/35905.
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The proliferation of wireless technology calls for the development of cost-effective Electromagnetic Interference (EMI) shielding materials that reduce the susceptibility of high-speed electronic circuits to undesired incoming radiation. Ideally, such materials offer protection over wide frequency ranges and are insensitive to the polarization or angle of incidence of the impinging fields. Here, next-generation EMI shielding materials composed of polymer composites with conductive and magnetic fillers are introduced. It is shown that careful control of the concentration and dispersion of the polymers’ conductive and magnetic constituents permits tuning of the composites’ intrinsic electrical and magnetic properties. The resulting EMI shields are lightweight, cheap and offer greater protection than traditional metal gaskets and foams. In this work, cobalt ferrite magnetic nanoparticles (CoFe2O4) decorated on graphene-based material were dispersed in polylactic acid (PLA) matrix for high EM absorption level in X-band (8-12 GHz). The decoration of the magnetic particles was performed on the as-prepared conductive graphene nanoplatelets (GNP) and reduced graphene oxide (rGO). GNP composites exhibited higher DC conductivity, and permittivity than rGO composites. This is attributed to issues associated with the reduction process, including a lack of conductivity due to the insulated oxygen functional groups and the reduction in the lateral size. Compared with rGOs, the lack of out-plane functional groups causes the cobalt ferrite nanoparticles to agglomerate and not cover the entire surface of the GNPs. These morphological differences improve the magnetization and EM absorption of the composite system. The compatibilizer (pyrene-PLA-OH) was added to the composites to enhance dispersion of the GNPs in the polymer matrix which benefits in higher absorption of the shield. The influence of the compatibilizer on parameter, the reflection loss (RL) of the composite were determined from the characterized intrinsic properties
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Tariq, Hanan Abdurehman, Abdul Shakoor, Jeffin James, Umair Nisar, and Ramzan Kahraman. "Combustion-Free Synthesis of Lithium Manganese Oxide Composites with CNTs/GNPs by Chemical Coprecipitation for Energy Storage Devices." In Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2020. http://dx.doi.org/10.29117/quarfe.2020.0004.
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Nano Spinel Lithium Manganese Oxide (LiMn2O4) was distributed properly on carbon nanotubes ( CNTs) and graphene nanoplatelets (GNPs) using chemical coprecipitation method. The original particle size was less than 40 nm, and the average size of the crystallite was 20 nm without the application of any capping agents. Characteristic spectra of spinel structure and a peak of CNTs & GNPs obtained using X-ray powder diffraction (XRD). CNTs and GNPs in energy storage systems improve the rate capabilities and cyclic efficiency of cathode materials. The suggested technique, chemical coprecipitation, provides new avenues for the production of nano-sized lithium transition metal oxide composites with CNTs and GNPs in an inexpensive and simple way. Higher density energy storage systems raise significant safety issues, and for safety, they are restricted to 30 percent to 50 percent of their ability. The proposed composite would enable the energy storage systems to be used even at high temperatures and higher discharge rates above 60 percent of their ability. Besides, the parasitic reaction between the electrode surface and the electrolyte will decrease, which will increase the battery's projected life span. As an all-solid-state device, the new composite batteries would make the system non-flammable, immune from side reactions, and resistant to capacity erosion.