A test method for measuring the dimensional stability of elastomeric materials upon heating

The dimensional stability of rubber products at elevated temperatures is a very important quality for improved capability. The present study introduces a new test method to estimate dimensional stability. The shrinkage and expansion forces that accompany the dimensional changes upon heating are measured under various test conditions, such as pre-strain or pre-stress. The dimensional changes were obtained from a length-sensing transducer, while the forces were recorded from a load cell as a function of time. The dimensional change of natural rubber (NR) was inversely proportional to the thermal stress recorded on heating. Using the new test method, the dimensional stability of rubber products upon heating was successfully evaluated by measuring the thermal stress as a function of time, rather than by measuring the length change.