Chapter 6 Scratching of polymers: Deformation mapping and wear modeling

Abstract

Scratching as a material testing tool has been around for well over 180 years [1] but despite many advantages, this technique has only recently found general acceptance by the engineers. Often the problem lies not in the testing method but in the deconvolution of the test results due to a lack of proper understanding of the stress field around a scratching tip and the boundary condition between the tip surface and the material. In this chapter, we will present some of the successes in the application of scratching for bulk polymer where this technique has provided insight into the materials surface damage characteristics. Examples are drawn from this author and coworkers' current and past works on the scratching of mainly bulk solid polymers. The first application example is taken from the work on scratching maps for polymers. Scratching technique has shown that often materials' deformation behavior, when faced with a sharp tip, is a strong function of the tip attack angle, normal load, scratching velocity and temperature. The second part of this chapter will focus on more recent results on the use of nano-scratching to understand the wear debris generation process for polymers. It is shown that cyclic intersecting scratching provides a hitherto unknown clue as to why some polymers, despite their low tensile strength, are more wear resistant than other stronger polymers. © 2006 Elsevier B.V. All rights reserved.