Rebound Resilience

ISO 8307, ASTM D3574 - H and  various factory standards

Purpose of the Test

Like all polymers, polymer foams demonstrate a visco-elastic behavior. This means that the mechanical characteristics depend to a greater or lesser degree on the temporal sequence of the applied deformation.

When calculating the material behavior, this characteristic is typically described by the storage modulus and the loss modulus. A higher storage modulus E‘ indicates a very elastic behavior, while a higher loss modulus E‘ indicates a high viscosity and thus, a strong dampening for faster deformation.

Measurement of the rebound height of a defined ball, which drops from a defined height onto the specimen surface, produces a value that indicates the ratio of the elastic percentage to the visco-elastic percentage of the mechanical behavior of a foam material. Since the viscose percentage is determined by elongation, uncoiling, and balling up processes, this measurement allows us to draw conclusions about the correct sequence of the foaming process.  A rebound height that is too low could indicate an incomplete chemical reaction. This method is a simple way to test as part of quality control.

Relevant Products

ZwickRoell's testing machine has a light barrier that automatically records the rebound height and thus, the rebound resilience. The test results can be transfered from the electronics to a PC via an interface.

In Germany, measurement is still partially done using a Schob pendulum. This method provides reproducible results and the test is easier to run, however it is no longer described in a valid standard. ZwickRoell offers a rebound resilience tester for this type of test (ZwickRoell 5109).

Standards for This Test

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