Superposition-based predictions of creep for polymer films at cryogenic temperatures

Abstract

The purpose of this study was to examine a novel application of superposition techniques for estimation of mechanical properties of polymer films at extreme cryogenic temperatures (e.g. 4 K). Polymer core films of the electronic laminates, ULTRALAM® 3850HT liquid crystal polymer (LCP) and Pyralux TK185018R (polyimide), were tested on a TA Instruments Q800 dynamic mechanical analyzer in tensile mode to obtain time-dependent creep compliance. Activation energy of flows, Ea, were calculated using an Arrhenius model. All data were accumulated within the range from about 150–293 K. Both polymers were found to have relaxation transitions within this range and predictions therefore initiated from the colder side of the transition. Predictive equations are proposed for creep compliance of these polymers. These compliances will be useful for overall failure models associated with devices ranging from electronics to magnetic cavities.