Living polymerization methods, importance

Living polymerization methods are an important part of macromolecular science and engineering. Since the initial reports of living anionic polymerizations, the field of living... 

The inverse problem is even more important. With living polymerizations, the number of generated macromolecules is given by the number of growth centres, i. e. by the amount of initiator molecules. The value of [N] can also be measured by a suitable physical method (see Chap. 8 Sect. 2.1). Therefore the number average degree of polymerization can be easily calculated ... 

The method suffers from several disadvantages. Probably the most important is that the rate constants for the reaction of the first and second living polymeric chains with the DPE derivative are different. This leads to bimodal distributions, due to the formation of both the dianion and the monoanion during the first step. This problem can be avoided by the addition of polar compounds (e.g., THF),but these compounds influence dramatically the microstructure of the polydienes. However, it was found that the addition of sec-butoxide to the living coupled product, prior to the addition of the diene monomer, can produce monomodal miktoarm stars while maintaining high 1,4 polydiene microstructure. 

The first chapter in this volume provides an overview of the current status of controlled/living radical pol5mierization (CRP) systems. The following three chapters discuss important issues relevant to all radical polymerization methods. The mechanistic and kinetic topics of ATRP are... 

An important aspect of polymer chemistry is the precise synthesis of polymers, which can be achieved most typically by living polymerization and by stereospecific polymerization. In particular, the former provides also methods of synthesizing end-functionalized... 

All of the more important methods of producing block polymers with long blocks utilize the living polymer method. To obtain definitive block lengths, the growing chain ends may not undergo termination or transfer reactions. Consequently, anionic polymerizations are more suitable than cationic polymerizations (see also Chapter 18). 

The most important achievement of living /controlled polymerization methods and techniques is the synthesis of tailor-made block copolymers with specific macromolecular architecture, chemical composition/functionality, low molecular polydispersity, and corresponding minimized heterogeneity. 

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