抄録
A micro-hardness tester based on the static indentation method was designed to study the hardness of polymer films. The contact area of a film with an indenter under loading was measurable in the terter. This tester has the following characteristics:
1) The error caused by elastic recovery characteristic of visco-elastic materials can be decreased.
2) The testing load changes continuously from 1g to 300g.
3) The testing temperature can be changes widely.
The results obtained by application of the tester are as follows;
i) The Vickers and Brinell hardness of thin polymer films was measured with an indenter under a proper small load. The hardness was independent upon the thickness of samples used in this experiment. A difference between the hardness under loaded and unloaded states for thin polymer films was observed. The hardness under unloaded state agreed with the value obtained by a commercial tester.
ii) In the case of uniaxially drawn PET, the shape of the contact area of the film with a ball indenter was ellipse, whose minor axis coincids with the drawing direction. The ratio of the major axis to the minor was proportional to the birefringence of the samples.
