Thermal Analysis of PTFE Electrical Wiring Insulation Material Subjected to Heat Treatment

摘要

One of the most widely used electrical wiring insulation materials is polytetrafluoroethylene (PTFE), -(CF_2)_n-, which possesses excellent temperature stability over a wide range of spectral frequencies, good chemical resistance, and superior insulating properties. PTFE has a semi-crystalline morphology with linear chains adopting complicated phases determined by environmental condition such as temperature and pressure. At temperatures below 19 °C at ambient pressure, it has a triclinic unit cell structure with a 13/6 helical conformation. From 19 to 30 °C at ambient pressure, it adopts a hexagonal unit cell structure with a 15/7 helical conformation. While at temperatures above 30 °C at ambient pressure, PTFE crystallizes in a pseudohexagonal unit cell structure with a 15/7 helical conformation. The characteristics of PTFE with different helical and crystalline structures are also sensitive to both thermal and mechanical history. The objective of this study is