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Basic Chemistry for the Synthesis of Telechelic Polyesters and Polycarbonates
Published in Sophie M. Guillaume, Handbook of Telechelic Polyesters, Polycarbonates, and Polyethers, 2017
Telechelic polymers are polymers with functional groups at both chain ends, of which selective reactions permit various functionalizations of the chain ends and further chain extension. In general, those telechelic polymers are synthesized by using “living” polymerization techniques. As shown in Scheme 1.1, the employment of initiators bearing certain functional groups gives the corresponding polymer chains with the initiating chain ends that inherit the functional groups from the initiators. Those functional groups are carefully selected or protected properly so that they survive the whole process of the living polymerization, that is, they do not react with the living propagating chain end. At the same time, those functional groups must not deactivate the propagating end in order to not hamper the efficient progress of the propagation reaction. Functional groups at the other side of the polymer chains can be introduced by reactions of the living chain ends with terminating reagents. By conducting selective reactions of the chain ends with terminating reagents bearing both reactive sites and extra functional groups, the chain ends can be endowed with the functional groups to give the corresponding telechelic polymers. Those functional groups should be selected from those not reactive with the living chain ends or should be protected properly so that they are compatible with the chain end functionalization reactions.
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Published in Eric J. Goethals, Telechelic Polymers: Synthesis and Applications, 2018
Telechelic polymers are usually bifunctional linear polymers having reactive groups at their extreme positions — chain ends. However, a number of telechelic polymers have functionality other than two; star trifunctional or tetrafunctional telechelic polymers are commercially available. Often telechelic polymers originally designed to be bifunctional have a distribution in the number of functional groups per molecule due to (undesirable) side reactions. Branched prepolymers with reactive groups which are at present often used in coatings can also be considered as telechelic polymers.
Copolymerization
Published in Charles E. Carraher, Carraher's Polymer Chemistry, 2017
Polymers that contain two reactive end groups are referred to as telechelic polymers. Joseph Shivers, a DuPont chemist, invented Spandex in 1959 after about a 10-year search. It was first named Fiber K but DuPont chose the more appealing, smooth-sounding trade name of Lycra.
Molecular design of supramolecular polymers with chelated units and their application as functional materials
Published in Journal of Coordination Chemistry, 2018
Igor E. Uflyand, Gulzhian I. Dzhardimalieva
Metallosupramolecular polymerization is a process of spontaneous self-assembly of polytopic organic ligands and metal ions with the formation of MSPs [50]. Metallosupramolecular polymerization requires that the chelating monomer is a telechelic system capable of continuous elongation of the chain in the presence of a metal ion through a well-known sequential polycondensation mechanism. The advantage of this concept is the ability to select the appropriate combination of M-L, which allows controlling the strength of the bond (thermodynamic characteristic) and the exchange rate (kinetic characteristic). The process of metallosupramolecular polymerization is mainly controlled by the M-L bond strength between the metal and the chelating block of the polytopic ligand. In the development of MSPs, special attention should be paid to some important factors that can be used to influence the polymer not only during, but also after the creation of the metallosupramolecular assemblies. The possibility of changing the polymer structure of MSP after its preparation has a significant advantage over covalent polymers.