The Ohio State University, United States
Keywords: Biorubber, critical materials security, advanced elastomers, liquid hydrogen, cryo-liquidsWe are developing the domestic semi-arid zone rubber crop, guayule, capitalizing on its unique elastomeric materials properties to allow entry into high-value un-met needs markets. Guayule natural rubber (GNR) can address the imperative for novel bio-elastomeric liquid hydrogen management materials with acceptable H2 permeability, flexibility at extremely cold temperatures, and high modulus. These novel materials can be used for seals, O-rings, gaskets, and hoses involved in H2 containment and H2-fueled vehicle delivery systems. GNR has intrinsic properties uniquely suited to this application, specifically: malleability at 77 K, a very high degree of crystallinity under stress (load or strain) which reduces void volume so limiting H2 entrapment, blistering and material permeability, high durability under deformation cycles, and resistance to damage during extreme temperature swings. GNR has 3x the filler loading capacity of imported NR, allowing high modulus materials to be made, which may open up the possibility of rubber-based H2 pipelines, overcoming a significant H2 infrastructure bottleneck. Other properties include acceptable H2 permeability, and storage modulus of at least 55 MPa, surpassing the 35 MPa required by lower pressure fuel dispensers. We aim to exceed 79 MPa to address higher pressure dispensers and gas cooling system dispenser apparatus.