Softening temperature of vulcanized CB reinforced natural rubber

Hi All. I intend to determine the softening temperature of carbon black loaded fully vulcanized natural rubber. I need to determine this in order to heat the rubber foam to change its structural characteristics. Can anyone please suggest a suitable method for determining this? And what do you think should be the approximate softening point of such type of rubber?

Thanks!

Farhan

There is an ASTM standard for heat deflection temperature.

Since most elastomers are used above the glass transition temperature, the modulus is a nice continuous function of the applied temperature. I am not so sure you will see a softening point.

-Jorgen