Polishing effect on nanoindentation behavior of nylon 66 and its nanocomposites

The effect of polishing on the near-surface mechanical properties of nylon 66 (PA66) and its clay nanocomposites has been investigated by a nanoindentation technique. The results show that polishing has significantly reduced the uncertainty in determining the surface property when performing nanoindentation experiments. In addition, polishing does not introduce serious strain hardening to a non-filled PA66 system, probably indicating that the polishing effect could be ignored for homogeneous polymer systems. For heterogeneous systems, especially for the injection-molded systems reinforced by nanofiller, polishing tends to expose the inner part of the sample, which may possess slightly different properties from that of the surface layer.