• 한국안전학회지
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• 제19권4호
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• pp.80-85
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• 2004

Electromagnetic interference(EMI) shielding characteristics of composite filled with Cu flake and carbon brush powder as hybrid conductive filler and EAF slag have been studied. The coaxial transmission line method of ASTM D4935-99 was used to measure the EMI Shielding effectiveness of composites as formulation in frequency rage $100\~1,000MHz$ The SE also increases with the increase in flier loading. The hybrid filler filled composites show higher SE compared to that of only Cu flake. The correlation between SE and conductivity of the various composites is also discussed. The results indicate that the composites having higher filler loading$({\geq}40wt.\%)$ can be used for the purpose of safety materials to protect hazardous electromagnetic interference.

• Composites Research
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• 제35권4호
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• pp.223-231
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• 2022

최근 미래 모빌리티 시장의 급격한 성장으로 자동차에 전장부품이 다량 탑재되면서 부품간 오작동을 최소화하기 위해 자동차 시장에서도 전자파 차폐에 대한 중요성이 커지고 있다. 이에 따라 전기전도성 고분자 복합소재(Conductive Polymer Composites, CPC)가 자동차용 차폐재로 각광받고 있으나, 산업에 일반적으로 요구되는 20 dB 이상의 전자파 차폐 성능 달성을 위해서는 고 함량의 전도성 필러 충진이 요구되므로 기계적 물성 향상, 원가 절감 측면에서 CPC의 전도성 필러 함량을 줄이기 위한 연구가 필수적이다. 본 논문에서는 이 중 필러 함량을 획기적으로 줄일 수 있는 Segregated structure 필러 네트워크 기반의 CPC를 제조하기 위한 공법들을 소개하고, 각 제조 공법 별 전자파 차폐 성능을 비교하고 분석하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.548-551
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• 1999

The cure characteristics of metal particle filled DGEBA/MDA/SN/ zeolite epoxy resin composite system for EMI shielding were investigated by dynamic DSC run method and FT-lR spectroscopy. As the heating rate increased, the peak temperature on dynamic DSC curve increased because of the rapid cure reaction. From the straight line of the Kissinger plot, the curing reaction activation energy and pre-exponential factor could be obtained. As the post-curing time at 15$0^{\circ}C$ increased, the glass increased the glass transition temperature or the thermal stability increased. When the post curing time is too long, the system filled with metallic Al particle can be thermally oxidized by the catalytic reaction of metal filler and the thermal stability of the composite for the EMI shielding application may be decreased.

• 전자공학회논문지 IE
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• 제43권4호
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• pp.122-127
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• 2006

무전해 도금법을 이용하여 고분자섬유의 형태를 가진 전도성 필러를 제조하였다. 나일론 6과 레이온 섬유 분체에 니켈과 구리를 도금한 복합 전도성 필러를 제조하였다. 입도 분석기를 이용하여 필러의 입자크기분포를 측정하였으며, 전도성 필러의 전도성을 측정하기 위해 전도성 분석기를 이용하였으며, 본 연구의 전도성 필러와 유사한 용도로 사용되는 탄소섬유의 전도성을 측정하여 전도성의 차이점을 비교하였다. ABS 수지에 제조된 전도성 필러를 주입하여 필름을 만들어서 1MHz$\sim$1GHz 주파수 대역에서 전자파 차폐 특성을 측정하였다. 제조된 전도성 필러가 첨가된 필름의 전자기파 차폐 특성을 측정하기 위하여 ASTM(D4935-89) 규격의 플랜지형 동축전송선 측정기구를 사용하였다. 제조된 전도성 필러는 기존의 탄소계 필러에 비해 전도성이 커서 전자파 차폐용 재료로 적합하였다.

• Elastomers and Composites
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• 제56권2호
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• pp.65-71
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• 2021

In recent times, the demand for electronic devices has increased because of advancements in the electronics industry. Consequently, research on shielding against electromagnetic interference (EMI) from electronic devices has also progressed significantly. In particular, research on imparting electrical conductivity to plastic has seen substantial progress. In this study, the effect of hybrid fillers comprising carbon fiber (CF) and carbon nanotubes (CNTs) on the electrical properties of polyamide 66 (PA66) composites was investigated. PA66 composites were prepared using a BUSS Co-Kneader single-screw extruder. EMI shielding effectiveness (SE) increased with the increasing addition of unsized CF (UCF), sized CF (SCF), and CNTs. For the PA66/SCF/CNT hybrid filler composites, EMI SE significantly increased with the increase in SCF content. Finally, the hybrid filler comprising SCF and CNTs may have a synergistic effect on the EMI SE and surface resistivity of PA66/SCF/CNT composites.

• 전력전자학회논문지
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• 제9권3호
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• pp.260-266
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• 2004

EMI필터는 주로 시행착오 법에 의해서 설계하기 때문에, 전력변환기기의 전도 EMI를 감쇠시키기 위해서는 많은 시간을 요하게 된다. 따라서 본 논문에서는 이러한 문제를 극복하기 위해서 EMI 필터에 대한 새로운 분석적인 설계절차를 제안한다. 각 부품에 대한 고주파 모델을 구성하고, 이러한 모델링 회로를 이용하여 각 모드에 적용할 수 있는 필터를 설계한다. 실제 사용되는 부품에 대한 축적된 데이터 베이스와 표준필터를 적용한 EUT(Equipment Under Test)의 측정 데이터를 기초로 해서 필터를 설계하는 알고리즘을 제안한다. 끝으로, 측정결과를 통해서 제안된 모델과 설계방법의 타당성을 확인한다.

• Carbon letters
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• 제24권
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• pp.41-46
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• 2017

The microstructure, flexural properties, electrical conductivity, thermal conductivity and electromagnetic interference (EMI) shielding effectiveness (SE) of epoxy composites filled with multi-walled carbon nanotubes (CNTs), exfoliated graphite nanoplatelets (xGnPs) and CNT-xGnP hybrid filler were investigated. The EMI SE of the CNT-xGnP hybrid composite was higher than 25 dB at 100 MHz while that of the xGnP based composite was almost zero. The flexural modulus of the CNT-xGnP based epoxy composite continuously increased to 3.32 GPa with combined filler content up to 10 wt% while that of the CNT based epoxy composites slightly decreased to 1.96 GPa at 4 wt% CNT, and dropped to 1.57 GPa at 5 wt% loading, which is lower than that of epoxy. The CNT and CNT-xGnP samples had the same EMI SE at the same surface resistivity, because samples with the same surface conductivity have the same amount of the charge carriers.

• 한국해양공학회지
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• 제23권3호
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• pp.35-39
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• 2009

The main objective of this study was to investigate fiber reinforced composite materials (FRCM) with electromagnetic shielding characteristics using aluminum (Al) film and copper (Cu) meshes. This study investigated the electromagnetic interference (EMI) shielding effectiveness (SE) of fiber reinforced composites filled with Al film, Cu meshes, and nano carbon black as hybrid conductive fillers to provide the electromagnetic shielding property of the fiber reinforced composites. The coaxial transmission line method of ASTM D 4935-89 was used to measure the EMI shielding effectiveness of composites in the frequency range of 300 MHz to 1.5 GHz. The variations of SE of FRCM with Al film, fine Cu, and general Cu meshes are described. The results indicate that the FRCM having Al film exhibited up to 75 dB of SE at 1.5 GHz.

• Macromolecular Research
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• 제10권5호
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• pp.253-258
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• 2002

The multi-wall carbon nanotubes (MWNTs) with graphite crystal structure were synthesized by the catalytic decomposition of a ferrocene-xylene mixture in a quartz tube reactor to use as the conductive filler in the binary polymer matrix composed of poly(vinylidene fluoride) (PVdF) and poly(vinyl pyrrolidone) (PVP) for the EMI (electromagnetic interference) shielding applications. The yield of MWNTS was significantly dependent on the reaction temperature and the mole ratio of ferrocene to xylene, approaching to the maximum at 800 $^{\circ}C$ and 0.065 mole ratio. The electrical conductivity of the MWNTs-filled PVdF/PVP composite proportionally depended on the mass ratio of MWNTs to the binary polymer matrix, enhancing significantly from 0.56 to 26.7 S/cm with the raise of the mass ratio of MWNTs from 0.1 to 0.4. Based on the higher electrical conductivity and better EMI shielding effectiveness than the carbon nanofibers (CNFs)-filled coating materials, the MWNTs-filled binary polymer matrix showed a prospective possibility to apply to the EMI shielding materials. Moreover, the good adhesive strength confirmed that the binary polymer matrix could be used for improving the plastic properties of the EMI shielding materials.

• Bulletin of the Korean Chemical Society
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• 제35권2호
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• pp.597-600
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• 2014

In this work, the electromagnetic interference shielding effectiveness (EMI-SE) of carbon nanotube/carbon fiber-reinforced HDPE matrix composites are investigated with various preparation conditions, such as the carbon fiber and carbon nanotube content, the presence of metal additives, as well as mixing speed and time. It was found that the EMI-SE of the composites increased with filler contents and metal additives. These results indicate that the content and length of carbonaceous fillers determine the electric networks in the composites, resulting in the control of the EMI-SE of the composites.