Abstract
In this study, the applicability of the PW method to filled rubber materials were examined.
A plot of PW value vs. Mooney viscosity shows a good straight line in analogy with that of unfilled rubber materials.
Similarly, the PW values are influenced by the penetrating rates. They are highly resolved at lower penetrating rate and even the slightest difference in platicity can be recognized. This is associated with the stress relaxation behavior of the materials strained by the needle surface.
Plots of log PW for unfilled materials and 1/PW for filled one vs. temperature give straight lines. These dependences of PW value on temperature are useful for the reduction of PW values from temperatures.
