Page 12 - Handbook of Surface Improvement and Modification

2.1 Methods and mechanisms of protection 7

Figure 2.5. Scratch features on PP/PA laminate. [Adapted, by permission, from Hamdi, M; Zhang, X; Sue, H-J,
Wear, 380-381, 203-16, 2017.]

Figure 2.6. Schematic of effect of MA 8 POSS loadings on scratch resistance and degree of conversion: (a)
MA 8 POSS loadings higher than 10 wt%, (b) MA 8 POSS loadings lower than 10 wt%. [Adapted, by permission,
from Chouwatat, P; Nojima, S; Higaki, Y; Kojio, K; Hirai, T; Kotaki, M; Takahara, A, Polymer, 84, 81-8, 2016.]

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or fish-scaling damage takes place. These damages are characterized by the material pile-
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up in front and on the side of the scratch tip. The transition region corresponds to the area
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between ironing and stick-slip. Ultimately, tearing damage occurs at the high scratch
loads. 6
The surface segregation effect is explained by the results of studies on influence of
polyhedral oligomeric silsesquioxanes on surface physical properties of acrylic hard coat-
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ing materials. Figure 2.6 demonstrates the effect of the degree of conversion at the outer-
most surface of the coating layer which was more suppressed than that of bulk, resulting in
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poor scratch resistance (Figure 2.6a). The outermost surface of the coating layer was cov-