On the temperature dependence of the cyclic compression behaviour of a thermoplastic vulcanizate elastomer

Effects of temperature on the uniaxial cyclic compression of a polypropylene based thermoplastic vulcanizate were studied in the range -40 degrees C-100 degrees C. The effect of temperature on the stress level was similar to that on the storage modulus from dynamic mechanical analysis. The residual strain after a cycle increased with decreasing temperature below 23 degrees C, while from 23 degrees C to 100 degrees C the effect of temperature was small. Both dependencies were correlated with the effect of temperature on the fraction of stress relaxed in the cycle. The residual strain after a cycle and the standard compression set (ISO 815-1, method A) had different temperature dependencies, and this was rationalized based on the different timescales of the tests and the different temperatures during loading and unloading. Two different methods for determining the Poisson's ratio in this temperature range were investigated in terms of measurement accuracy. The preferred method was based on input from dynamic mechanical analysis and triaxial compression.

Automated summary

This study investigated the effects of temperature on the uniaxial cyclic compression of a polypropylene based thermoplastic vulcanizate. The results showed that temperature had a similar effect on stress level and storage modulus. The residual strain after a cycle increased with decreasing temperature below 23 degrees C, while the effect of temperature was small from 23 degrees C to 100 degrees C. The study also compared two different methods for determining Poisson's ratio at different temperatures and found that the method based on dynamic mechanical analysis and triaxial compression was more reliable.