A telechelic polymer

Polymer

A polymer is a large molecule composed of repeating structural units. These subunits are typically connected by covalent chemical bonds...

 or oligomer

Oligomer

In chemistry, an oligomer is a molecule that consists of a few monomer units , in contrast to a polymer that, at least in principle, consists of an unlimited number of monomers. Dimers, trimers, and tetramers are oligomers. Many oils are oligomeric, such as liquid paraffin...

 is a prepolymer

Prepolymer

The term pre-polymer refers to a monomer or system of monomers that have been reacted to an intermediate molecular weight state. This material is capable of further polymerization by reactive groups to a fully cured high molecular weight state. As such, mixtures of reactive polymers with un-reacted...

 capable of entering into further polymerization

Polymerization

In polymer chemistry, polymerization is a process of reacting monomer molecules together in a chemical reaction to form three-dimensional networks or polymer chains...

 or other reactions through its reactive end-groups. It can be used for example to synthesize block copolymers.

By definition, a telechelic polymer is a di-end-functional polymer where both ends possess the same functionality. Where the chain-ends of the polymer are not of the same functionality they are termed di-end-functional polymers.

All polymers resulting from living polymerization

Living polymerization

In polymer chemistry, living polymerization is a form of addition polymerization where the ability of a growing polymer chain to terminate has been removed. This can be accomplished in a variety of ways. Chain termination and chain transfer reactions are absent and the rate of chain initiation is...

 are end-functional but may not necessarily be telechelic.

To prepare polymers by step-growth polymerization

Step-growth polymerization

Step-growth polymerization refers to a type of polymerization mechanism in which bi-functional or multifunctional monomers react to form first dimers, then trimers, longer oligomers and eventually long chain polymers. Many naturally occurring and some synthetic polymers are produced by step-growth...

, telechelic polymers like polymeric diols and epoxy

Epoxy

Epoxy, also known as polyepoxide, is a thermosetting polymer formed from reaction of an epoxide "resin" with polyamine "hardener". Epoxy has a wide range of applications, including fiber-reinforced plastic materials and general purpose adhesives....

 prepolymers can be used. The main examples are:

• Polyether diols;
• Polyester
  Polyester
  Polyester is a category of polymers which contain the ester functional group in their main chain. Although there are many polyesters, the term "polyester" as a specific material most commonly refers to polyethylene terephthalate...
  
   diols;
• Polycarbonate
  Polycarbonate
  PolycarbonatePhysical PropertiesDensity 1.20–1.22 g/cm3Abbe number 34.0Refractive index 1.584–1.586FlammabilityV0-V2Limiting oxygen index25–27%Water absorption – Equilibrium0.16–0.35%Water absorption – over 24 hours0.1%...
  
   diols: Polyhexamethylene carbonate diol (PHMCD);
• Polyalcadiene diols: Hydroxyl-terminated polybutadiene
  Hydroxyl-terminated polybutadiene
  Hydroxyl-terminated polybutadiene is a polymer of butadiene terminated at each end with a hydroxyl functional group. It reacts with diisocyanate to form polyurethane, a stable and easily stored synthetic material....
  
   (PBHT)...

Other examples of telechelic polymers are the halato-telechelic polymers or halatopolymers. The end-groups of these polymers are ionic or ionizable like carboxylate or quaternary ammonium groups.