Recently, scientists for the first time used a variant of carbon nanotubes with mechanically fixed ring molecules, MINT (mechanically interlocked carbon nanotubes), to strengthen plastic. The ring molecule is formed by closing the U–shaped base for the ring around the nanotube during synthesis. They do not interact chemically, the ring can move through the nanotube. This modification has significantly improved the mechanical properties of the material. The researchers reported on the results of the study in the journal Advanced Functional Materials. Annular organic molecules are attached to the nanotube, forming a strong and flexible bond.
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These molecules are formed by a separate seven-step synthesis. The mechanical fastening of the rings allows them to move relatively freely around the nanotube. The researchers added two amino groups to the rings to form covalent bonds with the polymer on the side of the ring. The properties of pure nanotubes can significantly deteriorate from the formation of a covalent bond with polymers. The researchers achieved complete stress transfer from the polymer to the nanotubes.
Their Young’s modulus, a measure of the possibility of resistance to stretching and compression, is one terapascal, which is five times higher than that of steel, while nanotubes are much lighter. Adding one percent of nanotubes by weight increases the Young’s modulus of the entire material by 77 percent, and the tensile strength by 100 percent.
