Tribological Behavior of Fluorinated and Nonfluorinated Polyimide Films

Abstract

In this study a series of polyimide (PI) films were synthesized from fluorinated and nonfluorinated monomers which contained diamines and dianhydrides. The influence of fluorine-containing groups on the glass transition temperature (T _g) and tribological properties of the PI films was investigated. The wear mechanism for the different kinds of PI polymers was comparatively discussed. T _g was characterized by dynamic mechanical analysis and the tribological changes were evaluated by friction and wear tests as well as scanning electron microscopy (SEM) analysis of the worn surfaces. Fourier transform infrared (FTIR) has been used to study the structures of the PI polymers. Experimental results indicated that the fluorine groups influenced the thermal behavior (T _g) of the PI films. Nonfluorinated PI films have lower friction coefficient and wear rate compared with the fluorinated ones. It was also found that the tribological properties of the PI films were closely related with the applied load. The friction coefficients and wear rates reduced with increasing the applied load.

Keywords:

• chemical structure
• fluorinated polyimide
• friction
• glass transition temperature
• synthesis
• wear

Acknowledgments

The authors would like to acknowledge the financial supports from the National Science Foundation for Distinguished Young Scholars of China (Grant No. 51025517), the National Nature Science Foundation of China (NSFC; Grant No. 51103168), and the National Defense Basic Scientific Research Project (A1320110011).