2.4.7. Hardness test
The hardness measurements for flexible PVC compounds were
done with a hardness tester PCE DX-A. The thickness of each sam-ple was around 3.5 mm and the Shore A and Shore D scale was
used as reference (Society for Testing and Standard, 2003 ); five
measurements were acquired for each sample and an average
value was calculated (assessing a maximum standard deviation
±1).