Polymer(Korea) (폴리머)

The Polymer Society of Korea (한국고분자학회)
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Failure Mechanism and Long-Term Hydrostatic Behavior of Linear Low Density Polyethylene Tubing

선형저밀도 폴리에틸렌 튜빙의 파손 메커니즘과 장기 정수압 거동

  • Weon, Jong-Il (Reliability Assessment Center for Chemical Materials, Korea Research Institute of Chemical Technology) ;
  • Chung, Yu-Kyoung (Reliability Assessment Center for Chemical Materials, Korea Research Institute of Chemical Technology) ;
  • Shin, Sei-Moon (Reliability Assessment Center for Chemical Materials, Korea Research Institute of Chemical Technology) ;
  • Choi, Kil-Yeong (Reliability Assessment Center for Chemical Materials, Korea Research Institute of Chemical Technology)
  • 원종일 (한국화학연구원 신뢰성평가센터) ;
  • 정유경 (한국화학연구원 신뢰성평가센터) ;
  • 신세문 (한국화학연구원 신뢰성평가센터) ;
  • 최길영 (한국화학연구원 신뢰성평가센터)
  • Published : 2008.09.30
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Abstract

The failure mechanism and failure morphology of linear low density polyethylene (LLDPE) tubing under hydrostatic pressure were investigated. Microscopic observations using video microscope and scanning electron microscope indicate that the failure mode is a brittle fracture including cracks propagated from inner wall to outer wall. In addition, oxidation induction time and Fourier transform infrared spectroscopy results show the presence of exothermic peak and the increase in carbonyl index on the surface of fractured LLDPE tubing, due to thermal-degradation. An accelerated life test methodology and testing system for LLDPE tubing are developed using the relationship between stresses and life characteristics by means of thermal acceleration. Statistical approaches using the Arrhenius model and Weibull distribution are implemented to estimate the long-term life time of LLDPE tubing under hydrostatic pressure. Consequently, the long-term life time of LLDPE tubing at the operating temperature of $25^{\circ}C$ could be predicted and also be analyzed.

정수압 상태의 선형저밀도 폴리에틸렌 튜빙의 파손 메커니즘과 파손 모폴로지를 연구하였다. 비디오현미경과 주사전자현미경을 이용한 관찰 결과, 선형저밀도 폴리에틸렌 튜빙의 파손모드는 내면에서 외면으로 진전되는 크랙을 수반하는 취성파괴임을 확인하였다. 또한 산화유발시간과 적외선분광분석을 통하여, 파손된 선형저밀도 플리에틸렌 튜빙의 단면상에 열화에 의한 발열 피크와 카르보닐 피크의 증가를 관찰하였다. 열 가속에 의한 음력과 수명특성 사이의 관계를 고려한 선형저밀도 폴리에틸렌 튜빙의 가속수명시험법 및 시험장치를 개발하였다. 선형저밀도 폴리에틸렌 튜빙의 장기 정수압 상태의 수명을 예측하기 위해 아레니우스 모델과 와이블 분포를 적용한 통계학적 기법을 도입하였다. 그 결과, 사용온도 $25^{\circ}C$에서의 선형저밀도 폴리에틸렌 튜빙의 장기수명을 평가/분석하였다.

Keywords

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