Silica-graphene nanoplatelets and silica-MWCNT composites: Microstructure and mechanical properties

Sharma, Nidhi; Alam, Syed Nasimul; Ray, Bankim Chandra; Yadav, Surekha; Biswas, Krishanu

doi:10.1016/j.diamond.2018.06.009

Cited by 11 publications

(12 citation statements)

References 41 publications

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“…These studies stated that the working performance of cement mixtures can be raised by the silanization of the selected additive. Silica has also gained considerable attention due to its ease of distribution, high modulus, electrical insulation, hardness, and extreme temperature sustainability [19]. Furthermore, the incorporation of silica into the cementitious mixture/mortar can improve the interfacial bonding of cement hydrates with modified carbon-based materials during the hydration reaction and a more compact structure can be obtained by filling the remaining voids in hydrated cement paste [12,[20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Synergistic Effect of Expanded Graphite-Silane Functionalized Silica as a Hybrid Additive in Improving the Thermal Conductivity of Cementitious Grouts with Controllable Water Uptake

et al. 2020

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Recently, a growing demand for geothermal applications has led to the exploitation of energy efficiently by developing grouting materials in the borehole between pipes and the ground. Therefore, the current study developed newly formulated cementitious grouts by the integration of expanded graphite (EG)-based hybrid additives synthesized by building chemical bridges between silica particles and EG in the presence of amino functional silane coupling agents. These produced hybrid additives with controlled EG and silica ratios were utilized in grout mixtures used in borehole heat exchangers to enhance the thermal conductivity. According to the optimization study on the formulation development of grout mixtures with bentonite, silica sands, cement, and superplasticizer by adding neat EG and EG-based hybrids, the relationship between the carbon amount and water demand was found to have a significant impact on thermal conductivity. The highest thermal conductivity value of 2.656 W/mK was achieved by the incorporation of 5 wt% hybrid additive with the ratio silica/EG of 1:5 compared to the reference grout, which showed a thermal conductivity of 2.373 W/mK. Therefore, the enhancement in thermal conductivity was dependent on the increase in the EG content and also the additive loading ratio, resulting in a slight increase in the water demand.

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Section: Introductionmentioning

confidence: 99%

Synergistic Effect of Expanded Graphite-Silane Functionalized Silica as a Hybrid Additive in Improving the Thermal Conductivity of Cementitious Grouts with Controllable Water Uptake

et al. 2020

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“…Moreover, the addition of graphene is expected to improve the wear behavior of the ceramic composites by forming tribofilms on the worn surface to provide lubrication effects. With less tangential force applied to the matrix grains, grain pull-out is impeded, leading to greatly reduced wear depth and wear rate in the 3 vol% GNP/SiO 2 composites [103]. Graphene sheets can also fill in the voids produced from wearing off of the matrix grains to provide an intact protecting film, resulting in an ultralow friction coefficient of ~0.5 in the 0.5 wt% GNP/Si 3 N 4 composites [94].…”

Section: Mechanical Properties and Applicationsmentioning

confidence: 99%

Controllable fabrication and multifunctional applications of graphene/ceramic composites

Huang¹,

Wan²

2020

J Adv Ceram

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Graphene with excellent comprehensive properties has been considered as a promising filler to reinforce ceramics. While numerous studies have been devoted to the improvement of mechanical and electrical properties, incorporating graphene to ceramics also offers new opportunities for endowing ceramics with versatility. In this review, the recent development of graphene/ceramic bulk composites is summarized with the focus on the construction of well-designed architecture and the realization of multifunctional applications. The processing technologies of the composites are systematically summarized towards homogeneous dispersion and even ordered orientation of graphene sheets in the ceramic matrix. The improvement of composites in mechanical, electrical, electromagnetic, and thermal performances is discussed. The novel multifunctional applications brought by smart integration of graphene in ceramics are also addressed, including microwave absorption, electromagnetic interference shielding, ballistic armors, self-monitor damage sensors, and energy storage and conversion.

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“…Fourier transform infrared transmittance spectroscopy (FTIR) was used to investigate the structural properties of MWCNTs and MWCNT/SiO 2 . More detailed SEM investigations [12][13][14] have reported that the majority of MWCNTs tend to interweave with one another; however, the surface characteristics of SiO 2 /MWCNTs are distinct. Moreover, multiple SiO 2 nanoparticles are densely and consistently dispersed on the surface of MWCNTs, significantly improving the roughness of the surface.…”

Section: Introductionmentioning

confidence: 99%

Morphological: Optical, and Mechanical Characterizations of Non-Activated and Activated Nanocomposites of SG and MWCNTs

et al. 2021

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Nanocomposites of silica gel (SG) and multiwalled carbon nanotubes (MWCNTs) of relatively low concentrations (0.25, 0.50, and 0.75 wt%) were characterized before and after annealing. Adsorption is a surface phenomenon, and based on this, the morphology of the composites was investigated by scanning electron microscopy (SEM). The produced images show that the MWCNTs were embedded into the silica gel base material. Fourier transform infrared (FTIR) transmittance spectroscopy showed that MWCNTs were not functionalized within the matrix of silica gel and MWCNT composites. However, after annealing the composites at 400 °C for 4 h in air, evidence of activation was observed in the FTIR spectrum. The effects of the embedding of MWCNTs on porosity, specific surface area, and pore size distribution were studied using Raman spectroscopy. The Raman spectra of the prepared composites were mainly dominated by characteristic sharp scattering peaks of the silica gel at 480, 780, and 990 cm−1 and a broad band centered at 2100 cm−1. The scattering peaks of MWCNTs were not well pronounced, as the homogeneity of the composite is always questionable. Nanosizer analysis showed that at 0.25 wt%, the distribution of MWCNTs within the silica gel was optimal. Vickers hardness measurements showed that the hardness increased with the increasing weight percent of MWCNTs within the composite matrix, while annealing enhanced the mechanical properties of the composites. Further studies are required to investigate the pore structure of silica gel within the matrix of MWCNTs to be deployed for efficient cooling and water purification applications.

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Silica-graphene nanoplatelets and silica-MWCNT composites: Microstructure and mechanical properties

Cited by 11 publications

References 41 publications

Synergistic Effect of Expanded Graphite-Silane Functionalized Silica as a Hybrid Additive in Improving the Thermal Conductivity of Cementitious Grouts with Controllable Water Uptake

Synergistic Effect of Expanded Graphite-Silane Functionalized Silica as a Hybrid Additive in Improving the Thermal Conductivity of Cementitious Grouts with Controllable Water Uptake

Controllable fabrication and multifunctional applications of graphene/ceramic composites

Morphological: Optical, and Mechanical Characterizations of Non-Activated and Activated Nanocomposites of SG and MWCNTs

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