• Bulletin of the Korean Chemical Society
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• v.31 no.8
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• pp.2261-2264
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• 2010

In this work, mechanical and electrical properties of graphenes (GP)/carbon nanotubes (CNTs) co-reinforced high density polyethylene (HDPE) matrix composites were studied. The microstructure, morphologies, and electric properties of the composites were evaluated by XRD, TEM, and 4-probe methods, respectively. It was found that the electric resistivity of 0.5 wt %-GP/HDPE was immeasurable, and 2.0 wt %-CNTs/HDPE showed high resistivity ($6.02{\times}10^4{\Omega}{\cdot}cm$). Meanwhile, GP (0.5 wt %)/CNTs (2.0 wt %)/HDPE showed excellent low resistivity ($3.1{\times}10^2{\Omega}{\cdot}cm$). This result indicates that the co-reinforcement systems can dramatically decrease electric resistivity of the carbon/polymer nanocomposites.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.3 s.234
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• pp.425-431
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• 2005

The efficiency of complex slurry preparation route for developing the high performance SiC matrix of $RS-SiC_{f}/SiC$ composites has been investigated. The green bodies for RS-SiC materials prior to the infiltration of molten silicon were prepared with various C/SiC complex slurries, which associated with both the sizes of starting SiC particles and the blending conditions of starting SiC and C particles. The characterization of Rs-SiC materials was examined by means of SEM, EDS and three point bending test. Based on the mechanical property-microstructure correlation, the process optimization is also discussed. The flexural strength of Rs-SiC materials greatly depended on the content of residual Si. The decrease of starting SiC particle size in the C/SiC complex slurry was effective for improving the flexural strength of RS-SiC materials.

• Advances in nano research
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• v.10 no.4
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• pp.327-337
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• 2021

In this review, composite structures are used for many industries for at least four decades. Polymeric composites are one of the important structures in the aerospace and aviation industry because of their high strength and low weight. In this comprehensive review, mechanical behaviors, physical and mechanical properties of polymeric composites, different types of reinforcements, different methods to fabricate polymeric composites, historical structural composite materials for aviation and aerospace industries, and also different methods for the characterization are reported. How to use various methods of composite preparation using different nanofillers as reinforcements and its effect on the physical properties and mechanical behavior of composites are discussed as well.

• Polymer(Korea)
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• v.36 no.5
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• pp.612-616
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• 2012

In this work, the effect of chemical treatments of multi-walled carbon nanotubes (MWNTs) on the mechanical interfacial properties of carbon fiber fabric-reinforced composites was investigated. The surface properties of the MWNTs were determined by acid and base values, Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) analyses. The mechanical interfacial properties of the composites were assessed by interlaminar shear stress (ILSS) and critical stress intensity factor ($K_{IC}$). The chemical treatments based on acid and base reactions led to a significant change of surface characteristics of the MWNTs, especially A-MWNTs/carbon fibers/epoxy composites had higher mechanical properties than those of B-MWNTs and non-treated MWNTs/carbon fibers/epoxy composites. These results were probably due to the improvement of interfacial bonding strength, resulting from the acid-base interaction and hydrogen bonding between the epoxy resins and the MWNT fillers.

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.5
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• pp.591-598
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• 2018

The reaction characteristics of aluminum-copper(II) oxide composites initiated by the electrostatic discharge were studied as changing the aluminum particle size. Three different sizes of aluminum particles with nano-size copper(II)-oxide particle were used in the study. These composites were manufactured by two methods i.e. a shock-gel method and a self-assembly method. The larger aluminum particle size was, the less sensitive and less violent these composites were based on the electrostatic test. On the analysis of high speed camera about ignition appearances and burning time, the burning speed was faster when aluminum particle size was smaller.

• Journal of the Korean Physical Society
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• v.73 no.10
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• pp.1437-1443
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• 2018

In this work, $SnO_2$ modified with reduced graphene oxide (rGO) and carbon nanotubes (CNTs) separately and combined sensitized by using the co-precipitation method and their sensing behavior toward ethanol vapor at room temperature were investigated. An interdigitated electrode (IDE) gold substrate is very expensive compared to a fluorine doped tin oxide (FTO) substrate; hence, we used the latter to reduce the fabrication cost. The structure and the morphology of the studied materials were characterized by using differential thermal analyses (DTA) and thermogravimetric analysis (TGA), transmission electron microscope (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Brunauer-Emmett-Teller surface area and Barrett-Joyner-Halenda (BJH) pore size measurements. The studied composites were subjected to ethanol in its gas phase at concentrations from 10 to 200 ppm. The present composites showed high-performance sensitivity for many reasons: the incorporation of $SnO_2$ and CNTs which prevents the agglomeration of rGO sheets, the formation of a 3D mesopourus structure and an increase in the surface area. The decoration with rGO and CNTs led to more active sites, such as vacancies, which increased the adsorption of ethanol gas. In addition, the mesopore structure and the nano size of the $SnO_2$ particles allowed an efficient diffusion of gases to the active sites. Based on these results, the present composites should be considered as efficient and low-cost sensors for alcohol.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1082-1083
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• 2006

Carbon nanotube (CNT) reinforced hydroxyapatite (HAp) composites were fabricated by using the spark plasma sintering process with surfactant modified CNT and HAp nano powder. Without the dependency on sintering temperature, the main crystal phase existed with the HAp phase although a few contents of ${\beta}-TCP$ (Tri calcium phosphate) phase were detected. The maximum fracture toughness, $(1.27\;MPa.m^{1/2})$ was obtained in the sample sintered at $1100^{\circ}C$ and on the fracture surface a typical intergranular fracture mode, as well as the pull-out pmhenomenon of CNT, was observed.

• Transactions on Electrical and Electronic Materials
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• v.13 no.5
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• pp.248-251
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• 2012

In order to develop a high voltage insulation material, epoxy/micro-silica composites (EMC) and epoxy/micro-silica/nano-silica composites (EMNC) with three different particle sizes in ${\mu}m$ and one particle size in nm were prepared and their tensile and flexural tests were carried out and the data was estimated by Weibull statistical analysis. The tensile strength of the neat epoxy was 82.8 MPa and those of the EMCs were larger than that of the neat epoxy, and they were much more advanced by the addition of 10 nm sized nano-silica to the EMCs. Flexural strength showed the same tendency of the tensile strength. As the micro-particle size decreased, tensile and flexural strength increased.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.11
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• pp.886-894
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• 2012

In order to develop electrical insulation materials, epoxy-nanosilica-microsilica mixture composites (ENMC) was synthesized, and mechanical properties such as their tensile and flexural strength, and AC insulation breakdown strength were investigated. Properties of mechanical strength and AC insulation breakdown strength are analyzed as scale and shape parameter with respect to weibull plot. Their tensile and flexural strength, AC insulation breakdown strength were compared original epoxy or EMC to ENMC. The 4 phr nano-silica addition and the 65 wt% micron-silica mixture composite (ENMC) was found to have the highest tensile and flexural strength. In the tensile strength was improved 29%, and flexural strength was improved 60.9% higher than those of the original epoxy. In the insulation breakdown strength, ENMC_4 phr was improved 17% and ENMC_5 phr was improved 15.8% higher than those of the EMC.

• Korean Journal of Materials Research
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• v.25 no.10
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• pp.531-536
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• 2015

GNPs have several excellent mechanical properties including high strength, a good young's modulus, thermal conductivity, corrosion resistance, electronic shielding, etc. In this study, CF/GNP/Epoxy composites were manufactured using GNP weight ratios of 0.15 wt%, 0.3 wt%, 0.5 wt%, 0.7 wt% and 1 wt%. The composites were manufactured with a mechanical method (3-roll-mill). Tensile, impact and wear tests were performed according to ASTM standards D3039, D256 and D3181, respectively. The results show that the CF/GNP0.3wt%/Epoxy composites have good mechanical properties, e.g., tensile strength and impact and wear resistance. In this study, both carbon fabric and GNPs were used as reinforcements in the composites. The mechanical properties increased and weight loss decreased as the GNP content in the resin films was increased.