Korean Chemical Engineering Research

The Korean Institute of Chemical Engineers (한국화학공학회)
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Effects of Annealing Process on the Crystallinity and Tensile Strength of PTFE

PTFE의 결정화도와 인장 강도에 미치는 풀림(annealing) 공정의 영향

  • Kim, Jung-Teag (Division of Applied Chemical Engineering, Pukyong National University) ;
  • Kim, Eun-Bong (Division of Applied Chemical Engineering, Pukyong National University) ;
  • Kim, Si-Young (Division of Applied Chemical Engineering, Pukyong National University) ;
  • Ju, Chang-Sik (Division of Applied Chemical Engineering, Pukyong National University)
  • 김정택 (부경대학교 응용화학공학부) ;
  • 김은봉 (부경대학교 응용화학공학부) ;
  • 김시영 (부경대학교 응용화학공학부) ;
  • 주창식 (부경대학교 응용화학공학부)
  • Received : 2009.08.20
  • Accepted : 2009.12.03
  • Published : 2010.02.28
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Abstract

In this work, we made experimental studies on the annealing process of PTFE(polytetrafluoroethylene) at $290{\sim}350^{\circ}C$ and examined the effects on crystallinity and tensile strength of PTFE. The experiments were performed at air atmosphere and the processes progressed up to 8 hours. From measuring tensile strength and SEM(scanning electron microscopy) observation, we could know PTFE was anisotropic material due to the band structure. Crystallinity of raw and annealed PTFE was measured by DSC(differential scanning calorimetry). As a result, crystallinity of annealed PTFE decreased and tensile strength increased. Also, we could verify the relation between crystallinity and tensile strength of annealed PTFE was linear. Raw PTFE, however, dropped out from the linear relation. Finally, PTFE annealed at $350^{\circ}C$ for 6 hours showed the smallest crystallinity and the largest tensile strength.

본 연구에서는 $290{\sim}350^{\circ}C$의 범위에서 PTFE(polytetrafluoroethylene)의 풀림(annealing) 공정을 수행하여, 결정화도와 인장 강도에 미치는 영향을 조사하였다. 풀림 공정은 대기압에서 진행되었고, 공정 시간은 8 시간까지 진행하였다. 인장강도의 측정 및 주사전자현미경(scanning electron microscope)의 측정을 통하여 PTFE 시편의 이방성을 확인하였다. 시차주사열량분석(differential scanning calorimetry)을 통하여 공정 전후의 결정화도를 측정하였고, 풀림 공정이 행해진 PTFE로부터 결정화도의 감소와 인장 강도의 증가를 확인하였다. 풀림 공정이 시행된 PTFE의 결정화도와 인장강도는 선형적 증감(增減) 관계를 나타내었지만, 풀림공정 시행 전의 PTFE는 이 선형 관계에서 벗어나 있었다. 그리고 풀림 공정온도가 $350^{\circ}C$이고 공정시간이 6 시간일 때, 가장 낮은 결정화도와 가장 높은 인장강도를 얻을 수 있었다.

Keywords

References

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