A new test methodology for evaluating scratch resistance of polymers

A new approach to conduct scratch tests on polymers is proposed. A brief review of the different definitions of scratch resistance and surface damages, currently available scratch test devices and the need for such a new approach is given. The new test methodology is developed using the concepts from materials science and solid mechanics, which include the consideration of material parameters, use of microscopy for image analysis and the finite element method (FEM). The consistency and reproducibility of test results are shown using a new scratch test device on two sets of neat and talc-filled polypropylene (PP) systems. Three different test conditions, i.e. linear load increase under constant speed, constant load under constant speed, and linear speed increase under constant load, have been conducted to determine the most effective, informative test conditions for evaluation of scratch resistance of polymers. The effect of loading and scratch speeds on the scratch-induced deformation of PP is also investigated using FEM simulations. Experimental observations and FEM results show a good qualitative correlation. The unique advantages of the new scratch test method for evaluating scratch resistance of polymers are discussed.