Creep behaviour of injection moulded polyamide 6/organoclay nanocomposites by nanoindentation and cantilever-bending.

R SELTZER; YIU-WING MAI; P FRONTINI

COMPOSITES PART B-ENGINEERING

ELSEVIER SCI LTD

Año: 2012 vol. 43 p. 83 - 89

1359-8368

The creep behaviour of injection moulded PA 6/organoclay nanocomposites was studied by depth-sensingnanoindentation and DMA cantilever-bending. The glass transitions of PA 6 and its nanocompositeswere decreased below room temperature upon saturation with water so that the materials could betested in the rubbery regime. For nanoindentation creep on the skin and core regions of injection mouldedsamples, whilst organoclay improves the creep resistance of PA 6, the enhancement is due to thedecrease of the initial compliance at zero time but the time-dependent creep is actually increased. In contrast,for cantilever-bending creep, organoclay reduces the creep compliance and the time-dependentcreep in PA 6. It is suggested that the organoclay imparts a constraint effect on the PA 6 molecular chains,restricting their mobility in the bulk compared to the surface and hence improving their resistance tocreep. A modified Halpin–Tsai equation was used to model their creep behaviour under these two loadingconfigurations and compared to experimental data.