The objective of this work is to determine the optimal process for manufacturing lightweight linerless cryogenic storage tanks using ionic liquid epoxy composite material that can compete with metallic tanks currently in use. Ionic liquids, because of their unique properties such as low volatility, low flammability, and flexibility of chemical design are showing promise as the next generation of chemical reagents. Mechanical and chemical testing to date has shown that this IL epoxy monomer, when cured with a commercial aromatic diamine curing agent, yields a polymer resin with high tensile strength, excellent bond strength to aluminum and steel, high toughness, low CTE, and low moisture permeability. Performance comparisons of the ILE to several commercial epoxies showed the ILE had superior tensile and bond strengths. Of particular importance is that these properties of the ILE were even better at cryogenic temperatures because of the low crystallinity inherent in the polymer as a consequence of the chemical nature of ionic liquids. In this Phase I effort, a battery of tests will be carried out at room and liquid nitrogen temperatures on coupons prepared preferably on a filament winder using the wet winding technique. Hand layup may also be used to make small defect-free samples. Samples for tensile, lap-shear and bend (for interlaminar shear strength) will be cut from these. Potholing or surface degradation, microcracking and delamination will be reported and quantified if found.
