Scratch behavior and material property relationship in polymers

The scratch behaviors of a broad range of polymers are investigated to understand how the material characteristics of a polymer affect the scratch resistance. A constant load scratch test and a progressive load scratch test are chosen for the present study. A scratch model proposed by Hamilton and Goodman is applied to correlate the mechanics and material parameters during the scratch process. An attempt is made to correlate the scratch behavior and basic material properties, such as the Young's modulus, yield stress, and tensile strength. A correlation between the scratch behavior and material surface characteristics, such as the friction coefficient, scratch hardness, and elastic recovery, under the current scratch tests are also made. Scratch subsurface damage in polymers is studied using optical microscopy. It is shown that shear yielding is the main cause of the plastic flow scratch pattern, while tensile tear on the surface and shear-induced fracture on the subsurface are the main damage mechanisms found in the fracture scratch pattern. The main causes for the susceptibility of thermoplastic polyolefins to scratch damage are discussed. Approaches for making scratch-resistant polymers are also addressed. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 47–59, 2001