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Published on: December 24, 2014
Polymer entanglement density and its influence on interfacial friction
Philip G Whitten1, Hugh R Brown
1Materials Engineering, University of Wollongong, Wollongong, New South Wales 2522, Australia.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|October 13, 2007
Summary
Polymer entanglement density dictates how glassy polymers deform during sliding friction, causing permanent plastic deformation. Friction force, however, remains independent of this entanglement density.
Area of Science:
- Materials Science
- Polymer Physics
- Tribology
Background:
- Entanglement density in amorphous glassy polymers influences fracture under tensile load.
- Previous studies suggest significant surface deformation of polymers during interfacial friction.
Purpose of the Study:
- To establish a direct correlation between polymer entanglement density and deformation mechanisms during sliding friction.
- To investigate the role of entanglement density in permanent plastic deformation and friction force.
Main Methods:
- Studied the topography of polymer surfaces after sliding with an inorganic glass sphere.
- Examined four different polymers, including polystyrene with varying cross-linking degrees.
- Analyzed the relationship between entanglement density and observed deformation patterns.
Main Results:
- A direct correlation was found between entanglement density and the deformation mechanisms enabling sliding friction.
- Permanent plastic deformation was observed during interfacial friction.
- The type of plastic deformation was directly dependent on the polymer's entanglement density.
- No significant difference in friction force was attributable to variations in entanglement density.
Conclusions:
- Polymer entanglement density is a key factor controlling plastic deformation during sliding friction.
- The observed friction phenomena align with state- and rate-dependent friction models.
- Understanding this relationship is crucial for predicting polymer behavior under tribological conditions.
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