Dear Andrew,

Belt elastic modulus is not single valued. It is dependent on the following:

1. tension or compression deformation - very non-linear

2. temperature can have extreme effect into the glass transition and is very non-linear see or papers on E';E"

3. histogram changes with use including Payne effect or Mullins effect

4. strain-rate can alter modulus such as cyclic frequency response and strain values can change the modulus

5. modulus can change with change in density which can be dependent on the above

What are you studying? How will you apply the knowledge? ■

Akron Rubber Development Laboratory, Inc.

Drummond, Jim ............................................ 330-434-6664

VP Physical Testing, Research & Development

300 Kenmore Blvd., Akron, OH 44301

FAX ............................................................... 330-434-8668 ■

As a side note:

If you take the same sample, at the same temperature, and execute the tensile modulus test with the exact same specifications, you will not obtain the same result. The higher the pulling force, the greater the difference in subsequent measurements.

I do not dispute you interest and your need to apply the procedure, I only wish to inform on some mysteries that may come to light. Polymers do not behave in similar ways to metals.

In a court of law, the properties need a comprehensive qualification, if they are applied to a question of engineering. ■