Quantitative Characterization of Scratch Damage in Polypropylene (TPO) for Automotive Interior Applications

A new test methodology for evaluating scratch resistance of polymers

“…A careful survey of the documentation on the existing test devices may also reveal that there exists little or no correlation of experimental test results with solutions computed analytically or numerically (e.g. from the FEM) [2,5,20,21,27,28], thereby restricting the interpretation of the experimental results solely via imprecise materials science reasoning.…”

“…Over the years, numerous scratch test devices have been built commercially or custom-built by researchers to study scratch responses of polymers at various length scales. At the macroscopic scale of testing, there are simplistic test methods like the pencil hardness test [18,19] and others that employ more sophisticated devices like the scratching machine [1,2,20,21], Taber test and pin-on-disc machine [5,22], Ford five-finger test [6,7,23,24], single-pass pendulum sclerometer [10][11][12]25], scratch apparatus [14], Revetest scratch tester [15], needle test [26], scratch test rig [27] and in-house scratch test apparatus [28]. To perform scratch tests at the micro-and nano-meter scales, one can turn to several commercially available machines, or customized test machines built by individual researchers [29][30][31][32][33].…”

Scratch behavior and material property relationship in polymers

“…A quantitative correlation between scratch damage and scratch visibility recently gained a great deal of attention. 2,5,30,31 It was reported that scratch visibility mainly depends on the yield zone size and fragmentation of the material surface during scratch, such as cracking, crazing, voiding, and debonding, in polymeric systems. 4,5 Engineering polymers may deform in different manners if the stress state varies [i.e., the dilatational stress dominant mode (triaxial tensile stresses) vs. the distortional stress dominant mode (shear stresses)].…”

An integrated approach towards the study of scratch damage of polymer

“…Simplistic test methods, like the pencil hardness test, 12,13 have been utilized for macroscopic scale scratch resistance evaluation. On the other hand, others employ more instrumented devices like the "scratching machine," [14][15][16][17] Taber test and pin-on-disc machine, 7,18 Ford five-finger test, 8,[19][20][21] single-pass pendulum sclerometer, [2][3][4]22 scratch apparatus, 23 Revetest scratch tester, 24 needle test, 25 scratch test rig, 9 in-house scratch test apparatus 26 and the "scratch tester." 27 For the micro-and nanometer scales evaluation, there are several commercially available machines, some of which are listed in reference 46, or customized test machines built by individual researchers.…”

“…Many attempts have been made to quantify scratch visibility by measuring the surface reflectivity of the scratch. [5][6][7][8][9][10] Due to the diverse techniques employed and the lack of systematic studies to correlate scratch features with visibility, 11 the results obtained from one set of experiments are often valid within a set of narrowly defined conditions. It remains to be seen which of these methods, if any, will prove to be the most useful in characterizing scratch visibility.…”