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Anodization of carbon fibers on interfacial mechanical properties of epoxy matrix composites.
Park, Soo-Jin,Chang, Yong-Hwan,Kim, Yeong-Cheol,Rhee, Kyong-Yop American Scientific Publishers 2010 Journal of Nanoscience and Nanotechnology Vol.10 No.1
<P>The influence of anodic oxidation on the mechanical interfacial properties of carbon-fiber-reinforced epoxy resin composites was investigated. The surface properties of the anodized carbon fibers were studied through the measurement of contact angles and through SEM, XPS, and FT-IR analyses. The mechanical interfacial properties of the composites were studied through measurements of interlaminar shear strength (ILSS), critical stress intensity factor (K(IC)), and critical strain energy release rate (G(IC)). It was shown that the surface functional groups containing oxygen on the anodized carbon fibers exert great effects on the surface energetics of fibers and the mechanical interfacial properties, e.g., ILSS, of the resulting composites. Contact angle measurements based on the wicking rate of a test liquid showed that anodic oxidation lead to an increase in the surface free energy of the carbon fibers, mainly in its specific (or polar) component. In terms of surface energetics, it was found that wetting played an important role in increasing the degree of adhesion at interfaces between the fibers and the resin matrices of the composites.</P>
Park, Soo-Jin,Oh, Jin-Seok,Rhee, Kyong-Yop Korean Carbon Society 2005 Carbon Letters Vol.6 No.2
In this work, the effects of atmospheric oxygen plasma treatment of carbon fibers on mechanical interfacial properties of carbon fibers-reinforced epoxy matrix composites was studied. The surface properties of the carbon fibers were determined by acid/base values, Fourier-transform infrared spectrometer (FT-IR), and X-ray photoelectron spectroscopy (XPS) analyses. Also, the crack resistance properties of the composites were investigated in critical stress intensity factor ($K_{IC}$), and critical strain energy release rate mode II ($G_{IIC}$) measurements. As experimental results, FT-IR of the carbon fibers showed that the carboxyl/ester groups (C=O) at 1632 $cm^{-1}$ and hydroxyl group (O-H) at 3450 $cm^{-1}$ were observed for the plasma treated carbon fibers, and the treated carbon fibers had the higher O-H peak intensity than that of the untreated ones. The XPS results also indicated that the $O_{1S}/C_{1S}$ ratio of the carbon fiber surfaces treated by the oxygen plasma led to development of oxygen-containing functional groups. The mechanical interfacial properties of the composites, including $K_{IC}$ (critical stress intensity factor) and $G_{IIC}$ (critical strain energy release rate mode II), were also improved for the oxygen plasma-treated carbon fibersreinforced composites. These results could be explained that the oxygen plasma treatment played an important role to increase interfacial adhesions between carbon fibers and epoxy matrix resins in our composite system.
Roles of metal/activated carbon hybridization on elemental mercury adsorption.
Bae, Kyong-Min,Kim, Byung-Joo,Rhee, Kyong Yop,Park, Soo-Jin American Scientific Publishers 2014 Journal of Nanoscience and Nanotechnology Vol.14 No.8
<P>In this study, the elemental mercury removal behavior of metal (copper or nickel)/activated carbon hybrid materials were investigated. The pore structures and total pore volumes of the hybrid materials were analyzed using the N2/77 K adsorption isotherms. The microstructure and surface morphologies of the hybrid materials were characterized by X-ray diffraction and scanning electron microscopy, respectively. In the experimental results, the elemental mercury adsorption capacities of all copper/activated carbon hybrid materials were higher than that of the as-received material despite the decrease in specific surface areas and total pore volumes after the metal loading. All the samples containing the metal particles showed excellent elemental mercury adsorption. The Ni/ACs exhibited superior elemental mercury adsorption to those of Cu/ACs. This suggests that Ni/ACs have better elemental mercury adsorption due to the higher activity of nickel.</P>
Yasser Zare,Kyong Yop Rhee,Soo Jin Park 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.86 No.-
This article develops a simple equation for the tunneling distance between neighboring carbonnanotubes (CNTs) in polymer CNTs nanocomposites (PCNTs) as a function of CNT concentration, CNTdimensions, interphase thickness, the percentage of networked CNTs, and the wettability of the CNTs bypolymer chains. The coupling of two developed models for the conductivity of PCNTs, assuminginterphase and tunneling effects expresses in this equation. The suggested equation calculates thetunneling distance for some PCNT samples at differentfiller concentrations, and expresses the impacts ofall the parameters on the tunneling distance. The appropriate predictions of the developed models for theconductivity of the samples and the acceptable levels of tunneling distance at various values of allparameters validate the suggested equation. The calculations indicate that the thinnest CNTs (radius of5 nm) and the largest CNTs (length of 5 mm) produced the shortest tunneling distance of 2.5 nm, but themaximum tunneling distance of 6.5 nm was observed at the CNT radius of 20 nm and length of 20 mm. Inaddition, the low surface energy of the polymer matrix and the high CNT surface energy result in a shorttunneling distance, but their roles in the tunneling distance are negligible.
Seong-Kwan PARK,Hi Jun CHOE,Mu-Young AHN,Kyong-Yop PARK 한국산업응용수학회 2006 한국산업응용수학회 학술대회 논문집 Vol.1 No.2
We consider the computational problems related to high voltage (HV) circuit breakers. To effectively design HV circuit breakers, a meshfree method which was proposed by the authors is tested. The meshfree method is implemented to a simplified model for the HV circuit breaker and showed a robust behavior even in a severe boundary condition. A good shock capturing is shown in the computations and a delicate gas diffusion through a slit is also computed, which is usually difficult to catch. Vector splitting method is employed to exploit the merit of mesh free methods in the hyperbolic problems.
Soo-Jin Park,Jin-Seok Oh,Kyong-Yop Rhee 한국탄소학회 2005 Carbon Letters Vol.6 No.2
In this work, the effects of atmospheric oxygen plasma treatment of carbon fibers on mechanical interfacial properties of carbon fibers-reinforced epoxy matrix composites was studied. The surface properties of the carbon fibers were determined by acid/base values, Fourier-transform infrared spectrometer (FT-IR), and X-ray photoelectron spectroscopy (XPS) analyses. Also, the crack resistance properties of the composites were investigated in critical stress intensity factor (KIC), and critical strain energy release rate mode II (GIIC) measurements. As experimental results, FT-IR of the carbon fibers showed that the carboxyl/ester groups (C=O) at 1632 cm-1 and hydroxyl group (O-H) at 3450 cm-1 were observed for the plasma treated carbon fibers, and the treated carbon fibers had the higher O-H peak intensity than that of the untreated ones. The XPS results also indicated that the O1S/C1S ratio of the carbon fiber surfaces treated by the oxygen plasma led to development of oxygen-containing functional groups. The mechanical interfacial properties of the composites, including KIC (critical stress intensity factor) and GIIC (critical strain energy release rate mode II), were also improved for the oxygen plasma-treated carbon fibersreinforced composites. These results could be explained that the oxygen plasma treatment played an important role to increase interfacial adhesions between carbon fibers and epoxy matrix resins in our composite system.
Samira Naghdi,Kyong Yop Rhee,Man Tae Kim,Babak Jaleh,Soo Jin Park 한국탄소학회 2016 Carbon Letters Vol.18 No.-
Graphene was grown on molybdenum (Mo) foil by a chemical vapor deposition method at different growth temperatures (1000°C, 1100°C, and 1200°C). The properties of graphene were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy, and Raman spectroscopy. The results showed that the quality of the deposited graphene layer was affected by the growth temperature. XRD results showed the presence of a carbide phase on the Mo surface; the presence of carbide was more intense at 1200°C. Additionally, a higher I2D/IG ratio (0.418) was observed at 1200°C, which implies that there are fewer graphene layers at this temperature. The lowest ID/IG ratio (0.908) for the graphene layers was obtained at 1200°C, suggesting that graphene had fewer defects at this temperature. The size of the graphene domains was also calculated. We found that by increasing the growth temperature, the graphene domain size also increased.