Esteban Broitman, Ph.D., Linköping University, Sweden

Speech Title: Principles of Polymer Tribology

Abstract:The science of tribology deals with the friction, wear, and lubrication of interacting surfaces in relative motion. Polymers and polymer composites are nowadays used in many tribological applications: tires, brakes, shoes, bearings, small moving parts, cosmetics/hair products, and biomedical joint implants.

This lecture reviews the processes which are generally regarded as being responsible for the frictional and wear behavior of polymeric solid bodies in contact. We will review contact mechanics with emphasis on the rheological (time dependent) properties of polymers and their relations to surface roughness, material properties, and friction, as well as wear behavior of rubbing polymer surfaces. We will discuss the three major processes taking place in polymer tribological interactions: deformation resulting in the real area of contact of rough surfaces, contact adhesion, and shear and rupture of materials in the contact during the sliding friction. Different tribological methodologies and will be compared, and measurements at the macro-, micro-, and nano-scale will be reviewed. Furthermore, we will discuss why polymers cannot be lubricated due to swelling and worsening of polymer tribological properties. Finally, we will show how the polymer properties in blending and combination with various fillers give rise to polymer nanocomposites with a variety of novel tribological applications.