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A D V A N C E D M A T E R I A L S & P R O C E S S E S | O C T O B E R 2 0 2 0 8 METALS | POLYMERS | CERAMICS of materials could have diverse military applications as well as aid in develop- ing more realistic prosthetics and soft robotics. tamu.edu . FUEL STORAGE WITH METAL ORGANIC FRAMEWORKS An interdisciplinary team from six institutions is examining heat transfer in metal organic frameworks (MOFs) and the role it plays when MOFs are used for storing fuel, discovering that keeping cool temperatures is essential for potential applications. “One of the challenges with using MOFs for fuel tanks in cars is that you have to be able to fill up in a few minutes or less,” ex- plain the researchers. “Unfortunately, when you quickly fill these MOF-based tanks with hydrogen or natural gas, they get very hot. The whole premise of using them to store a lot of gaseous fuel only works at room temperature.” As such, the research looked at thermal transport in MOFs to explore how quickly they can shed excess heat. They conducted two simultaneous ex- periments using two different methods and MOFs synthesized in two different A new family of polymers can self-heal, have shape mem- ory, and are recyclable. Courtesy of Matt Linguist/ Texas A&M Engineering. Depiction of metal organic frameworks (MOFS). Courtesy of Christopher E. Wilmer/University of Pittsburgh. VERSATILE SYNTHETIC MATERIALS Researchers at Texas A&M Univer- sity, College Station, and the U.S. Army Combat Capabilities Development Com- mand Army Research Laboratory, Adel- phi, Md., created a family of synthetic materials that range in texture from ultra-soft to extremely rigid by tweak- ing the chemistry of a single polymer. The researchers say their materials are 3D-printable, self-healing, recyclable, and naturally adhere to each other in air or under water. The researchers focused on the molecules involved in the crosslinking of elastomers. First, they chose a par- ent polymer, or prepolymer, and then chemically studded these prepolymer chains with two types of small crosslink- ing molecules—furan and maleimide. By increasing the number of these molecules in the pre- polymer, they found that they could create stiffer materials. In this way, the hardest material they creat- ed was 1000 times stronger than the softest. However, these cross- links are also reversible. Furan and maleimide par- ticipate in a type of revers- ible chemical bonding. In this reaction, furan and maleimide pairs can “click” and “unclick” depending on temperature. When the temperature is high enough, these molecules come apart from the poly- mer chains and the materials soften. At room temperature, the materials harden because the molecules quickly click back together, once again forming crosslinks. Thus, if there is any tear in these materials at ambient tempera- tures, the researchers showed that furan and maleimide automatically re- click, healing the gap within a few sec- onds. The scientists say the new group With a $4 million grant from the DOE, researchers from Missouri University of Science and Technology and Colorado School of Mines are working to prove the economic viability of increased renewable energy use in steel production. The project would create a system that combines a hydrogen-reduction reactor for ironmaking (H2DR) with electric furnace melting for steelmaking. energy.gov. BRIEF