Improved testing system for thermomechanical experiments on polymers using uniaxial compression equipment

This paper presents an improved testing system for isothermal and thermal-cycling experiments of polymers in compression. Due to the low thermal conductivity of polymers and the high thermal mass of commercially available compression platens, significant problems arise; large differences between the prescribed and polymer temperature, temperature variation through the sample and a slow temperature response are observed. Here, in experiments performed on an acrylic network polymer, the largest temperature difference between the core of the cylindrical compression samples (10 mm diameter/height) and the prescribed air temperature reaches 20.7 °C and 64.8 °C when respective cooling/heating rates of 1 °C/min and 10 °C/min are used. Based on the analysis of the existing system, an improved compression platen design for thermal management that provides a faster temperature response and a more uniform sample temperature distribution is proposed. The peak temperature difference was reduced to 4.5 °C at a cooling/heating rate of 10 °C/min using the improved testing system.