Nanoindentation of advanced polymers under non-ambient conditions: creep modelling and tan delta.
The creep modelling approach described in this paper reveals a correlation between the strain rate sensitivity parameter determined from room temperature nanoindentation data and tan delta determined from conventional dynamic mechanical analysis (DMA). With recent advances in nanomechanical instrumentation it is possible to obtain reliable raw data under non-ambient conditions. Nanoindentation tests on polymeric films at elevated temperature provide support for the correlation, with high values of the high strain rate sensitivity parameter only observed in the vicinity of the glass transition temperature. Analysis of the shapes of the indentation loading curves at elevated temperature has revealed a sharp decrease in the loading curve exponent near the glass transition. The nanoindentation approach holds promise for assessment of actual components (e.g., micro-moulded components) where production of DMA test pieces is not feasible.
Gray
Ashley
A
Micro Materials Ltd, Byre Units 1-3, Wrexham Technology Park, Wrexham, LL 13 7YP, UK.
Orecchia
David
D
Beake
Ben D
BD