A tripolymer was a type of chemical substance.
Pralor Automated Personnel Units were powered by a type of chromo-dynamic module powered by a tripolymer plasma. B'Elanna Torres in 2372 found an unit which was "dying" because the plasma was contaminated. (VOY: "Prototype")
Bathar of Hodos, a salesman traveling the Delta Quadrant in the 24th century, claimed to have a formula that stopped the ageing process. In reality it was only a tripolymer enzyme though. Chakotay laconically remarked that it did made a great shoe polish. (VOY: "Memorial")