热氧老化对聚酯薄膜力学和电性能的研究

通过对电机用聚酯薄膜在不同热氧老化温度下进行了加速热处理,讨论了热处理温度对材料的力学和电性能影响因素。结果表明,随着热氧老化温度提高,薄膜电气强度和局放电压逐渐增大,拉伸强度、断裂伸长率、表面电阻率、介质损耗因数逐渐下降;相对电容率、体积电阻率变化不大。经分析,这些性能的变化主要与聚对苯二甲酸乙二醇酯(PET)薄膜黏度下降和结晶度增加有非常大的关系,黏度下降影响占主导地位。

Study on Mechanical and Electrical Properties of Polyester Film by Thermal Oxygen Aging

The accelerated heat treatment of polyester film for motor under different thermal oxygen aging temperature was carried out,and the influence factors of heat treatment temperature on the mechanical and electrical properties of the material were discussed.The results show that with the increase of thermal oxygen aging temperature,the breakdown voltage and partial discharge voltage of the film increase gradually.The tensile strength,elongation at break,surface resistivity and dielectric loss factor decrease gradually,and the relative permittivity and volume resistivity change little.According to the analysis,the changes of these properties are mainly related to the decrease of viscosity and the increase of crystallinity of polyethylene terephthalate(PET)films,the influence of viscosity decrease is dominant.