Evaluation of carbon fiber composites fabricated using ionic liquid based epoxies for cryogenic fluid applications

AbstractUtilizing tanks fabricated from fiber reinforced polymeric composites for storing cryogenic fluids such as liquid oxygen and liquid hydrogen is of great interest to NASA as considerable weight savings can be gained. Unfortunately such composites, especially at cryogenic temperatures, develop a mismatch that initiates detrimental delamination and crack growth, which promotes leaking. On-going work with ionic liquid-based epoxies appears promising in mitigating these detrimental effects. Some recent results are presented and discussed

The growth of tubular or vermicular structures in organic monotectic systems

Growth fronts have been examined for several transparent organic monotectic alloys based on succinnonitrile (SCN), using a temperature gradient stage. The systems include SCN with water, glycerol, benzene, and ethanol: in the first two systems, steady state growth is possible at very low rates ( \u3c 1 μm s-1), while in the latter pair, nonsteady state conditions apply at all growth rates (\u3e 0.1 μm s-1). At higher growth rates ({succeeds or equivalent to}1 μm s-1) all these systems exhibit a variety of tubular or vermicular morphologies, where droplets of the minor immiscible liquid phase appear to provide a diffusion path by which the reaction can occur with localized deposition of the solid product. The remarkable growth forms are discussed with reference to a series of time-lapse micrographs and the form of a typical phase diagram