화학공학소재연구정보센터
홈 로그인 로그아웃 연락처 사이트맵
Applied Chemistry for Engineering, Vol.22, No.2, 138-143, April, 2011
Export Citation
열처리 온도에 의한 구조 결정성이 탄소섬유의 전자파 차폐 성능에 미치는 영향
The Effect of Crystallization by Heat Treatment on Electromagnetic Interference Shielding Efficiency of Carbon Fibers
김종구, 정철호, 이영석†
  • 충남대학교 공과대학 정밀응용화학과
Jong Gu Kim, Choul Ho Chung, and Young-Seak Lee†
  • Department of Fine Chemical Engineering and Applied Chemistry,BK21-E2M, Chungnam National University, Daejeon 305-764, Korea
E-mail:
초록
열처리 온도에 따른 탄소섬유의 전자파 차폐특성을 알아보고자 전기방사법을 이용하여 나노섬유를 제조하고 1073, 1323, 1873, 2573 K의 온도 조건에서 열처리 공정을 실시하여 서로 다른 탄소 결정화도를 갖는 PAN계 탄소섬유를 제조하였다. 장방출 주사전자현미경을 통하여 제조된 섬유의 표면 형상을 조사하였고 열처리 온도에 따른 탄소섬유의 결정화도를 Raman 분석을 통하여 확인하였다. 또한 결정화도에 따른 전기전도성을 알아보고자 4-탐침법을 이용하여 표면저항을 측정하고 전기전도성을 계산하였으며, 회로망 분석기를 이용하여 800∼4500 MHz의 주파수 영역에서 S-parameter를 측정하고 유전율 및 투자율, 그리고 전자파 차폐 특성을 조사하였다. 2573 K에서 제조된 탄소섬유의 경우 Raman 분석을 통하여 Ig/Id 값이 2.66으로 1323 K에서 제조된 탄소섬유의 1.08에 비해 2.4배 증가하여 결정화도가 향상됨을 확인하였고 전기전도성 또한 54.7 S/cm로 약 6배의 향상을 확인하였다. 유전율 실수부에서는 평균 20의 수치를 보여 1323 K에서 제조된 탄소섬유와 비교하여 약 4배의 향상을 보였다. 결과적으로 열처리 온도에 따른 탄소의 결정화도 향상에 의해 전자파 차폐 성능이 평균 41.7 dB로 약 10 dB이 향상되었음을 확인하였다.
To investigate the electromagnetic interference shielding efficiency (EMI SE) property based on heat treatment effects of carbon fibers in various temperatures, the polyacrilonitrle-based carbon fibers were prepared by electrospinning method and treated at 1073, 1323, 1873 and 2573 K. The surface morphology of carbon fibers was investigated by using FE-SEM and the carbon crystallization was studied by Raman spectroscopy based on effects of reaction temperatures. The electrical conductivity was obtained by measuring the surface resistance with four probe method on carbon crystallization. The permittivity, permeability and EMI SE were investigated by using S-parameter in the range of 800∼4500 MHz. In case of carbon fibers treated at 2573 K, the improved carbon crystallization was confirmed by Raman spectrum and the enhanced electrical conductivity showing 54.7 S/cm was also observed. The permittivity was dramatically improved by factor of 4 based on effect of high reaction temperature. Eventually, the highly improved EMI SE value was obtained showing around 41.7 dB.
Keywords:carbon fiber;graphite;electromagnetic interference;electrospinning;heat treatment
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