• Composites Research
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• v.36 no.3
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• pp.217-223
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• 2023

In this work, the preparation and its oil adsorption behavior of polyacrylonitrile-based carbon nanofiber sponge were investigated. The prepared carbon sponges showed excellent selective oil adsorption in the mixture of water and oil, and the adsorption capacity of reused carbon nanofiber sponge was also investigated. Further, carbon nanofiber sponge adsorbent with internally structured channel showed fast oil adsorption behavior due to a capillary phenomenon. After use, sponge adsorbent was heat-treated at 800℃ under N² and studied the possibility of a sensor for electrochemical detection of 4-aminophenol.

• Tribology and Lubricants
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• v.24 no.5
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• pp.269-274
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• 2008

Carbon nanotube composite is considered to be a good candidate material for composite material because of its excellent mechanical property and low density under high temperature as well as good wear and frictional properties. In this study, tribological characteristics of carbon nanotube aluminum composite were evaluated using pin-on-disk wear tester. Spark Plasma Sintering method is more effective than Hot Pressing method in terms of wear and friction. The composite with 1% CNT has the lowest friction and wear characteristic.

• Composites Research
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• v.19 no.2
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• pp.28-34
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• 2006

[ $Cu-TiB_2$ ] metal matrix composites with various weight fractions of $TiB_2$ were fabricated by combination of manufacturing process, SPS (self-propagating high-temperature synthesis) and SPS (spark plasma sintering). The feasibility of $Cu-TiB_2$ composites for welding electrodes and sliding contact material was investigated through experiments on the tensile properties, hardness and wear resistance. To obtain desired properties of composites, composites are designed according to reinforcement's shape, size and volume fraction. Thus proper modeling is essential to predict the effective material properties. The elastic moduli of composites obtained by FEM and tensile test were compared with effective properties from the original Eshelby model, Eshelby model with Mori-Tanaka theory and rule-of-mixture. FEM result showed almost the same value as the experimental modulus and it was found that Eshelby model with Mori-Tanaka theory predicted effective modulus the best among the models.

• Polymer Science and Technology
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• v.21 no.2
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• pp.149-156
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• 2010

전기방사 탄소섬유와 s-VGCFs는 그 미세구조의 특성 때문에 응용분야가 서로 다르다. 전기방사 탄소나노섬유는 유기물을 섬유화하고 그것을 탄화하기 때문에 VGCFs에 비해서 낮은 가격에 대량생산이 가능하고 촉매를 사용하지 않기 때문에 전극으로 사용할 경우 금속불순물에 대한 부반응의 우려가 없다. 한편, 결정성이 낮고 세공이 잘 발달되어 비표면적이 크기 때문에 이온을 흡착해서 에너지를 저장하는 전기화학 캐패시터나 가스 흡착 분리나 촉매의 지지체로 사용하는데 장점이 있다. 이에 비해서 s-VFCFs는 섬유의 직경이 기존의 VGCF에 비해서 작으면서 잘 발달된 흑연구조가 동심원 구조를 하고 있어 굴곡강도가 크고 열 및 전기전도도가 우수하여 납축전지나 Li 이온전지의 충전제로 사용하여 역학적 특성과 향상시켜 주는 역할을 한다. 또한, 금속과 복합화하여 가벼우면서도 강도를 증가시켜주는 보강재로 사용가능하다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.226-226
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• 2014

난삭재에 대한 관심이 증가하면서 최근 공구시장에서는 고경도, 고내열성을 갖는 코팅물질에 대한 연구가 진행되고 있다. 따라서 두 장점을 모두 가진 나노복합구조를 가진 박막에 대한 연구가 진행되고 있으며 특히 경도에 영향을 미치는 나노결정립과 내열성에 영향을 주는 비정질층의 비율을 조절하는 연구에 집중하고 있다. 따라서 본 연구에서는 질소분압이 변화시키며 CrZrSiN 박막의 물성 변화를 확인하였다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.33 no.6
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• pp.203-209
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• 2023

Cobalt sulfide nanocomposites were synthesized through a simple hydrothermal method as anode materials for sodium ion batteries (SIBs). In this work, a cobalt sulfide nanoparticle (CoS-NF) and a cobalt sulfide nanocomposite integrated with reduced graphene oxide (CoS@G-NC) were fabricated for electrochemical energy storage performance of battery. The as-prepared CoS@G-NC electrode exhibited reversible and stable cycle performance (62 % after 30 cycles at current density of 200 mA g^-1). The improved electrochemical property was attributed to the small grain growth and uniform distribution of cobalt sulfide during synthesis, which maximized the diffusion pathway for sodium ions and effectively suppressed the delamination and volume expansion of cobalt sulfide during the conversion reaction. The results provide promising anode materials for next-generation SIBs.

• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.1
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• pp.62-67
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• 2011

Nanoparticles-coated and impact-damaged carbon-fiber reinforced plastics(CFRP) laminates were tested under compression-after-impact(CAI) mode and the propagation of damage due to compressive loading has been monitored by acoustic emission(AE). The impact damage was induced not by mechanical loading but by a simulated lightning strike. CFRP laminates were made of carbon prepregs prepared by coating of conductive nano-particles directly on the fibers and the coupons were subjected to simulated lightning strikes with a high voltage/current impulse of 10~40 kA within a few microseconds. The effects of nano-particles coating and the degree of damage induced by the simulated lightning strikes on the AE activities were examined, and the relationship between the compressive residual strength and AE behavior has been evaluated in terms of AE event counts and the onset of AE activity with the compressive loading. The degree of impact damage was also measured in terms of damage area by using ultrasonic C-scan images. From the results assessed during the CAI tests of damaged CFRP showed that AE monitoring appeared to be very useful to differentiate the degree of damage hence the mechanical integrity of composite structures damaged by lightning strikes.

• Polymer(Korea)
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• v.30 no.1
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• pp.75-79
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• 2006

Silica nanoparticles for polymeric dental restorative composites were prepared by Stober method, and then the effects of surface treatment of silica particles with Lmethacrylofpropyltrimethofsilane $(\gamma-MPS)$ on the dispersity of the silica particles in the organic matrix was investigated. Particles having various average size were prepared by using controlled amounts of tetraethylorthosilicate(TEOS), water, and catalyst and by changing solvent used for reaction. The site of particles prepared by using methanol as solvent was smaller than that prepared by using ethanol as solvent. In addition, the size of particles was increased by decreasing amounts of water and by increasing amounts of TEOS and catalyst. Hydrophobic silica nanoparticles was prepared by reacting hydrophilic nanoparticles with $\gamma-MPS$ to improve interfacial properties with organic matrix. Amounts of $\gamma-MPS$ per unit mass of the particles was increased by decreasing particle size. even though the amount of $\gamma-MPS$ per specific surface area were nearly the same regardless of the particle size. The dispersity of the silica particles in the organic matrix was improved when the surface treated silica particles were used for preparing the polymeric dental restorative composites.

• Fashion & Textile Research Journal
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• v.13 no.2
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• pp.279-284
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• 2011

In this study, the process of preparation nonwoven with coated carbon nano fibers (CNFs) /poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) composite solution is described. The various contents of CNFs/PVDF-HFP composite coated nonwoven were prepared and characterized by morphological, mechanical, and electrical methods. Nonwovens are coated with CNFs/PVDF-HFP composite solution and decreased the pick up ratio with increasing CNFs contents in range from 0% to 16%. In the results of SEM images, it was clear that the CNFs were evenly distributed in coated nonwoven by SEM images, the existence of CNFs in coated nonwoven was confirmed regularly. The mechanical properties of various contents of CNFs/PVDF-HFP coated nonwoven were examined. The tensile linearity and compression linearity increased with increasing CNFs contents. The electrical properties of the CNFs/PVDF-HFP coated nonwoven increased with increasing CNFs contents.

• Journal of Powder Materials
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• v.15 no.3
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• pp.188-195
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• 2008

Carbon nanotube (CNT)/$Mg_2Ni$ composites were synthesized to enhance the hydrogen storage properties. The emphasis was made on the effect of different shortening methods of CNTs on the open-tip structure and the resulting properties. The use of open CNTs as a starting material resulted in an enhanced hydrogen properties of CNT/$Mg_2Ni$ composites. Among the employed methods for the shortening of CNTs, wet milling using ethanol was the most efficient, while ultrasonic acid treatment or thermal decomposition resulted in a less hydrogen storage capacity.