The Effects of Cryogenic Temperature on Material Properties of Polymers

Material Properties of Kapton and Liquid Crystal Polymers under Cryogenic Conditions

            A significant array of devices now require operation under cryogenic conditions including certain electronics, sensors, superconducting magnets in accelerators and medical devices based on super conductors. These devices must be warmed to room temperature for maintenance, which presents a thermal challenge to the device potentially resulting in mechanical failure. These devices may include polymeric components (a dielectric) such as Kapton or liquid crystal polymers (LCP). Material properties such as the coefficient of thermal expansion (CTE) and dynamic modulus are important for the prediction of device response to thermal challenge. We discuss the frequency and temperature dependence for Kapton and LCP thin films reaching from room temperature to liquid nitrogen temperatures, tested using Dynamic Mechanical Analysis. So from the analysis done so far, Kapton NR showed a change in storage modulus of approximately 1000 MPa from -150 degrees Celsius to room temperature and also had a final storage modulus of 4700 MPa. LCP showed a change in storage modulus of around approximately 4500 MPa at the same temperature range and also showed a final storage modulus of 11000 MPa. These values are an average done of different tests ran at different frequencies in a Q800 Dynamic Mechanical Analysis instrument.