• Carbon letters
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• 제15권2호
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• pp.117-124
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• 2014

Conductive polymer composites (CPCs) consist of a polymeric matrix and a conductive filler, for example, carbon black, carbon fibers, graphite or carbon nanotubes (CNTs). The critical amount of the electrically conductive filler necessary to build up a continuous conductive network, and accordingly, to make the material conductive; is referred to as the percolation threshold. From technical and economical viewpoints, it is desirable to decrease the conductive-filler percolation-threshold as much as possible. In this study, we investigated the effect of polymer/conductive-filler interactions, as well as the processing and morphological development of low-percolation-threshold (${\Phi}c$) conductive-polymer composites. The aim of the study was to produce conductive composites containing less multi-walled CNTs (MWCNTs) than required for pure polypropylene (PP) through two approaches: one using various mixing methods and the other using immiscible polymer blends. Variants of the conductive PP composite filled with MWCNT was prepared by dry mixing, melt mixing, mechanofusion, and compression molding. The percolation threshold (${\Phi}c$) of the MWCNT-PP composites was most successfully lowered using the mechanofusion process than with any other mixing method (2-5 wt%). The mechanofusion process was found to enhance formation of a percolation network structure, and to ensure a more uniform state of dispersion in the CPCs. The immiscible-polymer blends were prepared by melt mixing (internal mixer) poly(vinylidene fluoride) (PVDF, PP/PVDF, volume ratio 1:1) filled with MWCNT.

• Design & Manufacturing
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• 제10권3호
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• pp.14-19
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• 2016

Thermally or electrically conductive filler reinforced polymer composites are extensively being developed as the demand for light weight material increases rapidly in industiral applications need good conductivity such as heat sink of the electronics or light. Carbon or ceramic materials like graphite, carbon nanotube or boron nitride are typical conductive fillers with good thermal or electical conductivity. Using these conductive fillers, the polymer composites in the market show wide range of thermal conductivity from approximately 1 W/mK to 20 W/mK, which is quite enhanced considering the thermal conductivity lower than 0.5 W/mK for most polymeric materials. The practical use of these composites, however, is yet limited to specific applications because most composites are still not conductive enough or too difficult to process, too brittle, too expensive for higher conductivity. For practical use of conductive composite, the thermal conductivity required depending on the heat releasing mode are studied first for simplified unit cooling geometry to propose thermal conductivities of the composites for reasonable cooling performance comparing with the metal heat sink as a reference. Also, as a practical design for heat sink based on polymer composite, composite and metal sheet hybrid structures are investigated for LED lamp heat sink and audio amplication module housing to find that this hybrid structure can be a good solution considering all of the cooling performance, manufacturing, mechanical performance, cost and weight.

• Elastomers and Composites
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• 제33권5호
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• pp.355-362
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• 1998

전도성 충전제인 카본블랙이 미치는 영향을 올바로 이해하므로서 전도성 카본블랙을 충전하여 도전성 고분자 복합재료를 제조하고자 하였다. 고분자 수지로 ABS(Acrylonitrile Butadiene Styrene copolymer), PC(Polycabonate), PC/ABS 를 사용하여 전도성 카본블랙 3종류를 사용하여 비교하였다. 실험결과 섬유사슬모양의 전도성 카본블랙을 충전한 PC는 상당히 가능성을 보였다.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2004년도 춘계학술발표대회 논문집
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• pp.147-150
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• 2004

Graphite reinforced conductive polymer composites were fabricated by the compression molding technique. Graphite powder (conductive filler) was mixed with an epoxy resin to impart electrical property in composites. The ratio of graphite powder was varied to investigate electrical property of cured conductive composites. In this study, graphite filled conductive polymer composites with high filler loadings$(>60wt.\%)$ were manufactured to accomplish high electrical conductivity(> 100S/cm). Graphite powder increase electrical conductivity of composites by direct physical contact between particles. While high filler loadings are needed to attain good electrical property, the composites becomes brittle. So the ratio of filler to epoxy was varied to optimize of cured composites. The optimum molding pressure according to filler was proposed experimentally.

• 폴리머
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• 제24권2호
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• pp.276-280
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• 2000

폴리아크릴로니트릴 (PAN) 직물을 매트릭스로 하여 전도성고분자인 폴리피롤(PPy)과 전도성 복합재료 직물을 제조하였다. 복합재료의 제조는 PAN 직물을 피롤과 산화제를 포함하는 용액에 일정 시간동안 함침하여 직물상에서 전도성 고분자의 중합을 in-situ로 유도하는 방법을 이용하였다. 복합재료의 물성을 최적화 하기 위한 반응 조건을 설정하였으며, 이때 arylsulfonate 계통의 도판트를 부가적으로 첨가하여 이들이 복합재료의 물성에 미치는 영향을 검토하였다. 본 연구에서 실험한 다양한 종류의 도판트 중에서 antraquinonesulfonate (AQSA)가 부가적으로 첨가된 전도성 PAN 직물이 가장 우수한 전기전도도와 열적 안정성 및 세탁 견뢰도를 나타내었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 하계종합학술대회 논문집
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• pp.349-352
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• 1989

Poling piezoelectric ceramic-polymer composites with 0-3connectivity is difficult because of the high dielectric constant of most of the ferroelectric filler materials, and the high resistivity of the polymer matrix. To aid in poling this type of composite, conductivity of the polymer phase can be controlled by adding small amount of a semiconductor phase such as germanium, carbon or silicon. In this study, flexible piezoelectric composites of $PbTiO_3$ powder and Eccogel polymer were developed using small amounts of a semiconducting phase. These composites were poled rapidly at low voltages, resulting in properties superior to composites prepared without a conductive phase. The effect of addition of various conductive phase with different volume percentage on the dielectric and piezoelectric properties of the composite are discussed here.

• 폴리머
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• 제25권2호
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• pp.293-301
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• 2001

새로운 복합재료 제조 기술인 electron-ion technology (EIT)를 이용하여 전도성 탄소섬유/고밀도 폴리에틸렌 (CF/HDPE) 복합필름을 제조하고 탄소섬유 에폭시 sizing이 제조된 필름의 체적비저항과 인장강도 그리고 계면 특성에 미치는 영향에 대하여 연구하였다. 에폭시 sizing은 tunneling 효과를 좋게 해서 복합재료 필름의 전도성을 향상시키는 반면, 극성인 에폭시 sizing은 무극성인 폴리에틸렌과의 친화성이 없어서 탄소섬유와 폴리에틸렌간의 계면결합력을 감소시키므로 에폭시 sized 탄소섬유(CF(S))는 unsized 탄소섬유(CF(U))에 비하여 필름의 체적비저항과 인장강도를 감소시켰다. 에폭시 sizing은 탄소섬유의 nucleating efficiency를 떨어뜨려서 CF(S)/HDPE 필름이 CF(U)/HDPE 필름보다 불규칙적이고 덜 발달된 transcrystalline layer를 형성함을 관찰할 수 있었다.

• 한국전기전자재료학회논문지
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• 제35권3호
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• pp.203-214
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• 2022

Thermoelectric (TE) heating and cooling devices, which are able to directly convert thermal energy into electrical energy and vice versa, are effective and have exhibited a potential for energy harvesting. With the increasing consumer demands for various wearable electronics, organic-based TE composite materials offer a promise for the TE devices applications. Conductive polymers are widely used as flexible TE materials replacing inorganic materials due to their flexibility, low thermal conductivity, mechanical flexibility, ease of processing, and low cost. In this review, we briefly introduce the latest research trends in the flexible TE technology and provide a comprehensive summary of specific conductive polymer-based TE material fabrication technologies. We also summarize the manufacture for high-efficiency TE composites through the complexation of a conductive polymer matrix/inorganic TE filler. We believe that this review will inspire further research to improve the TE performance of conductive polymers.

• 폴리머
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• 제37권4호
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• pp.513-517
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• 2013

고내열성 고분자인 폴리벤족사진(PBZ)과 전도성 그래핀을 혼성화시켜 새로운 전도성 복합박막을 제조하는 연구를 처음으로 수행하였다. 단순한 열처리 공정에 의해 동시에 그래핀 옥사이드와 벤족사진 단량체를 환원 및 경화를 시켜 기계적/전기적 특성이 크게 향상된 그래핀/PBZ 복합 박막을 제조하였다. 그래핀/PBZ 복합 박막의 화학/결정 구조 및 형태학적 미세구조 분석으로부터 약 3 wt%의 그래핀이 복합 박막에 들어가더라도 그래핀이 비교적 균일하게 분산된다는 것을 알 수 있었다. 본 연구를 통하여 PBZ박막의 기계적 물성 향상과 동시에 도전성을 부여하는 효과적인 경로를 제공할 수 있었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 추계학술대회 논문집
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• pp.265-266
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• 2010