Formation of Micro-porous Structure of Polytetrafluoroethylene Film and Fiber

• Main Authors: Wan-Chih Chung, 鍾宛芷
• Other Authors: Tien-Wei Shyr
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/90043535018166544416

碩士 === 逢甲大學 === 纖維與複合材料學系 === 99 === This study is focused on the formation of micro-porous in polytetrafluoroethylene (PTFE) film and fiber by uniaxial tensile fracture, axial tear fracture and stretching cycles. The thermal properties and crystal structure in three different morphology including PTFE powder, film and fiber were analyzed. The thermal behaviors of PTFE powder, film and fiber were investigated by using a differential scanning calorimeter (DSC). The micro-porous morphology of PTFE film and fiber were observed by using a scanning electron microscope (SEM) after tensile fracture. The crystal structure of PTFE powder, film and fiber were analyzed by using a high resolution x-ray diffractometer (HRXRD). DSC results showed that low-temperature melting peaks of PTFE were no significant change with the different processing conditions. The high-temperature melting peaks are observed at 370 ℃ and 380 ℃of PTFE film and fiber respectively which is caused by drawing process. Morphology observation of micro-porous PTFE indicated the island-like node is perpendicular to the tensile direction and the fibril is parallel to the tensile direction on the surface by stretching cycles. The pearl-like node and fibril is observed parallel to the tensile direction in the inside of PTFE film after axial tear process. The membrane-like structure is found in the tensile fracture PTFE fiber which is located perpendicular to the tensile direction and fibril structure is parallel to the tensile direction on the surface and inside. The WAXD curve showed that the crystal orientation of PTFE fiber is increased by drawing and it caused the increment in the intensity of main diffraction peak (100).