• Polymer Science and Technology
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• v.24 no.1
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• pp.30-37
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• 2013

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.508-510
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• 1987

The variation electrical resistivity of Carbon black filled polymers with volume percent of carbon black was investigated. The relationships between the surface tension of polymer and dispertion effect of carbon black were studied to find the steep drop of electrical resistivity. The critical volume percent of carbon black increased with the increasing surface tension of polymer. The PTC intensity decreased with the increasing volume percent of carbon black.

• Proceedings of the Korean Fiber Society Conference
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• 2001.10a
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• pp.320-323
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• 2001

일반적으로 고분자 재료는 그 자체로는 전기가 통하지 않는 전기절연체이나 여기에 카본블랙, 카본파이버, 금속분말 등 전도성을 가지는 입자들을 가지고 도핑할 경우 전기가 통하는 반도체 특성을 지니는 재료로 변화를 한다. 특히, 전기ㆍ전자재료 분야에서 이러한 특성을 이용한 재료 중 하나인 PTC 소자는 나노 크기를 가지는 카본 블랙과 고분자 재료의 복합화를 바탕으로 하여 과전류에 의한 발열의 감지 및 전류를 차단함으로서 회로를 보호하는 소자를 말하는 것으로서 현재 그 수요량이 급격히 증대하고 있는 기능성 재료중 하나이다. (중략)

• Journal of the Korean Ceramic Society
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• v.49 no.4
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• pp.352-362
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• 2012

This paper explores the use of a variety of carbon nanoparticles to impart electrical, thermal conductivity, good frictional properties to silicon nitride matrices. We used the highly promising types of carbon as carbon nanotubes, exfoliated graphene and carbon black nanograins. A high-efficiency attritor mill has also been used for proper dispersion of second phases in the matrix. The sintered silicon nitride composites retained the mechanical robustness of the original systems. Bending strength as high as 700 MPa was maintained and an electrical conductivity of 10 S/m was achieved in the case of 3 wt% multiwall carbon nanotube addition. Electrically conductive silicon nitride ceramics were realized by using carbon nanophases. Examples of these systems, methods of fabrication, electrical percolation, mechanical, thermal and tribological properties are discussed.

• Bulletin of the Korean Chemical Society
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• v.34 no.7
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• pp.2155-2161
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• 2013

Composite materials of mesoporous carbon and carbon nanotubes were synthesized using Ni, Co and Pd-loaded CMK3 via a catalytic reaction of methane and $CO_2$. The CNTs grew from the pores of the mesoporous carbon supports, and they were attached tightly to the CMK3 surface in a densely tangled shape. The CNT/CMK3 composite showed both non-graphitic mesoporous structures, and graphitic characteristics originating from the MWCNTS grown in the pores of CMK3. The electrochemical properties of the materials were characterized by their electrorheological effects and cyclic voltammetry. The CNTs/CMK3 composites showed high electrical conductivity and current density. The CNT/CMK3 or KOH-modified CNT/CMK3 particles were incorporated in a PMMA matrix to improve the thermal and electrical conductivity. Even higher thermal conductivity was achieved by the addition of KOH-modified CNT/CMK3 particles.

• Bulletin of the Korean Chemical Society
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• v.35 no.8
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• pp.2251-2256
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• 2014

We have successfully decorated reduced graphene oxide (RGO) with silver nanoparticles (AgNPs) by microwaving silver alkylcarbamate for 13 seconds using 1-amino-4-methylpiperazine. Uniform AgNPs (20-40 nm) were effectively prepared, and 1-amino-4-methylpiperazine acted as a reaction medium, reducing agent, and stabilizer. Particle size and morphology were correlated with the silver alkylcarbamate concentration and microwave time. The graphene/AgNPs composites were characterized by Raman, X-ray diffraction, and scanning electron microscopy to confirm that the AgNPs were uniformly decorated onto the graphene. Measurements of the transparent conductive property at room temperature indicated that these graphene/AgNPs nanosheets with 55.45% transmittance were electrically continuous with a sheet resistance of approximately $43{\Omega}/{\Box}$.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.131-134
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• 2004

The object of this study is to design the Radar Absorbing Structures (RAS) having sandwich structures in the X-band $(8.2\~12.4GHz)$ frequencies. Glass fabric/epoxy composites containing conductive carbon blacks and carbon fabric/epoxy composites were used for the face sheets. Polyurethane (PU) foams containing multi­walled carbon nanotube (MWNT) were used for the core. Their permittivities in the X-band were measured using the transmission line technique. The reflection loss characteristics for multi-layered sandwich structures were calculated using the theory of transmission and reflection in a multi-layered medium. Three kinds of specimens were fabricated and their reflection losses in the X-band were measured using the free space technique. Experimental results were in good agreements with simulated ones in 10dB absorbing bandwidth.

• Polymer(Korea)
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• v.24 no.5
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• pp.673-681
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• 2000

Electrically conductive composites have been prepared by treating fabrics with oxidizing agent and exposing them to aniline, which deposited a substantial amount of conductive polymer within the interstices of the material. However the conductivity of the composite fabrics was limited by the irregular deposition of the conductive polymer layer. To improve the conductivity of polyaniline/nylon 6 composite fabrics, we modified the surface characteristics of nylon 6 fabrics by various plasma treatments and increased diffusion and adsorption of aniline by ultrasonic treatments. By the oxygen plasma treatment, attachment of functional groups such as C-O and C-OH increased on the surface of nylon 6 fiber, which promoted adhesion to polyaniline resulting in the higher add-on and electrical conductivity. Electrical conductivities of polyaniline/nylon 6 composite fabrics were highly increased by ultrasonic treatment, which assisted the diffusion of aniline into the inside of nylon fabrics by cavitation and vibration. Also, the effects of monomer concentration and the number of deposition cycles on the nylon 6 fabric conductivity Were investigated. As a result, the fabric conductivity increased with the monomer concentration and the number of polymerization deposition cycles.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2001.04a
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• pp.35-43
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• 2001

Flip chip assembly on organic substrates using ACAs have received much attentions due to many advantages such as easier processing, good electrical performance, lower cost, and low temperature processing compatible with organic substrates. ACAs are generally composed of epoxy polymer resin and small amount of conductive fillers (less than 10 wt.%). As a result, ACAs have almost the same CTE values as an epoxy material itself which are higher than conventional underfill materials which contains lots of fillers. Therefore, it is necessary to lower the CTE value of ACAs to obtain more reliable flip chip assembly on organic substrates using ACAs. To modify the ACA composite materials with some amount of conductive fillers, non-conductive fillers were incorporated into ACAs. In this paper, we investigated the effect of fillers on the thermo-mechanical properties of modified ACA composite materials and the reliability of flip chip assembly on organic substrates using modified ACA composite materials. Contact resistance changes were measured during reliability tests such as thermal cycling, high humidity and temperature, and high temperature at dry condition. It was observed that reliability results were significantly affected by CTEs of ACA materials especially at the thermal cycling test. Results showed that flip chip assembly using modified ACA composites with lower CTEs and higher modulus by loading non-conducting fillers exhibited better contact resistance behavior than conventional ACAs without non-conducting fillers. Microwave model and high-frequency measurement of the ACF flip-chip interconnection was investigated using a microwave network analysis. ACF flip chip interconnection has only below 0.1nH, and very stable up to 13 GHz. Over the 13 GHz, there was significant loss because of epoxy capacitance of ACF. However, the addition of $SiO_2filler$ to the ACF lowered the dielectric constant of the ACF materials resulting in an increase of resonance frequency up to 15 GHz. Our results indicate that the electrical performance of ACF combined with electroless Wi/Au bump interconnection is comparable to that of solder joint.

• Composites Research
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• v.26 no.5
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• pp.315-321
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• 2013

In this work, pitch-carbonized glass fibers were prepared for reinforcement of composites. The influence of acid functionalization of the fibers on the morphological, mechanical, and thermal properties of fiber-reinforced epoxy matrix composites was investigated. The acid functionalization of the fibers led to 10 and 150% increases in the mechanical and thermal properties, respectively, as compared to carbon fiber-reinforced composites. This can be attributed to the superior orientation of fiber structures and good interfacial interactions between fillers and epoxy matrix, resulting in enhanced degree of dispersion and formation of thermally conductive paths in the functionalized composites.