聚酰亚胺-聚四氟乙烯复合材料的制备和表征

Preparation and characterization of PI-PTFE compsite materials

利用共混挤出工艺制备聚酰亚胺-聚四氟乙烯(PI-PTFE)复合材料,考察PTFE含量对复合材料热性能、摩擦性能及力学性能的影响。结果表明:制得的PI-PTFE复合材料两相不相容,复合材料的最高使用温度为250℃,在250℃以下复合材料的尺寸稳定性较好,其线膨胀系数随PTFE含量的增加而增大,不受热循环历程的影响;复合材料分解质量损失5%的温度(t5d)为525℃,热分解速率随PTFE含量的增加而增大;干摩擦时,随PTFE含量的增加,复合材料的摩擦因数降低,磨损率呈上升趋势;复合材料的拉伸强度、弯曲强度和硬度均随PTFE含量的增加而降低,就力学性能而言,PTFE的添加量不超过20%为宜。

Polyimide-polytetrafluoroethylene（PI-PTFE） composite materials were prepared by mixing-extrusion processing.The influence of the composition on the thermal properties,mechanical properties,and tribological behavior of composites was investigated.Results showed that phase separation was observed in the composite.The maximum application temperature was 250 ℃ with a better dimensional stability.The coefficient of thermal expansion was unaffected by thermal circles and increased with the increase of PTFE contents,and the t5d was 525 ℃.The thermal decomposition rate increased with the increase of PTFE contents.In a dry friction environment with the increase of the PTFE contents,the coefficient of friction reduced while the wear rate increased.Meanwhile,the tensile strength,flexural strength and hardness decreased with the increase of PTFE contents.The suitable amount of PTFE in the PI-PTFE composite materials was lower than 20%.