Orientation and the extent of exfoliation of clay on scratch damage in polyamide 6nanocomposites

Abstract

The major objectives of this work are to understand the effects of organoclay, its extent ofexfoliation and orientation, and indenter geometry on the scratch characteristics ofpolyamide 6/organoclay nanocomposites. Two different organically treated clays are usedfor this purpose and their structural parameters in a polyamide 6 matrix quantified. It isshown that, while the material properties are important for scratching resistance, they arenot the only determinants of the scratch performance of materials. Further, despite provingbeneficial to scratch resistance, in terms of residual depth, the presence (and exfoliation) oforganoclay promotes the formation of brittle cracks during scratching. But with noorganoclay layers, plastic flow controls the scratch damage in neat polyamide 6 with largeresidual depths. Factors such as orientation of clay layers and variations of indentertip geometry also exert dominant effects on scratch penetration resistance anddamage. Additionally, significant plastic flow and rotation of organoclay layersfrom the original configuration are observed underneath the sliding indenter.