Telechelic

Telechelic refers to a polymer that bears reactive functional groups at its chain ends, enabling further chemical reaction, chain extension, or crosslinking. The term combines tele- (distant) with chelic (hand), reflecting the idea of reactive ends at the ends of a polymer chain. In practice, telechelic polymers are typically prepared so that both chain ends carry functional groups, though mono-telechelic variants (functional at one end) are also encountered.

Common end groups used for telechelic polymers include vinyl or acrylate groups, epoxides, isocyanates, amines, hydroxyls, thiols, and carboxyls. These end groups enable subsequent reactions such as radical or cationic polymerization, condensation, or crosslinking with complementary functionalities. Telechelics are frequently produced via living or controlled polymerization methods where a difunctional terminator or chain-terminating agent is employed, yielding macromonomers that retain reactivity at both ends.

Applications of telechelic polymers are varied. They serve as macromonomers in the synthesis of linear or network polymers, star polymers, and block copolymers. They are used in adhesives, coatings, and thermosetting resins where end-group reactions drive crosslinking. In polyurethane and epoxy chemistries, telechelic polymers with appropriate end groups enable rapid curing and tailored network structures. Telechelic polymers also find use in smart materials and rheology-modifying additives, where end-group chemistry influences processing and final properties.

Key considerations include end-group fidelity, stability under processing conditions, and compatibility with reaction partners. The choice of end group determines the type of subsequent chemistry and the network architecture that can be achieved.