Gun barrels. The missing piece from a 3D printed firearm. Oh hell yeah.
Could be - stack the discs and drill a hole down the middle, or roll the sheets into tubes (although resistance to heat and abrasion may be an issue). The article notes: "Although it’s extremely thin and lightweight, the polymer has a yield strength that’s twice that of steel, and it takes up to six times more force to deform it than bulletproof glass." To me, that also sounds like 'body armor'...