Click chemistry polymerization

The polymeric/ soft materials chapter represents the largest expansion for the 2nd edition. This chapter describes all polymeric classes including dendritic polymers, as well as important additives such as plasticizers and flame-retardants, and emerging applications such as molecular magnets and self-repairing polymers. This edition now features click chemistry polymerization, silicones, conductive polymers and biomaterials apphcations such as biodegradable polymers, biomedical devices, dmg delivery, and contact lenses. 

Lee, Y.G., Koyama, Y, Yonekawa, M.,andTakata, T. (2009) New click chemistry polymerization based on 1,3-dipolar cycloaddition of a homo ditopic nitrile N-oxide and transformation of the resulting polymers into reactive polymers. Macromolecules, 42,7709. 

Finally, Lecomte and coworkers reported the synthesis of mikto-arm star-shaped aliphatic polyesters by implementing a strategy based on click chemistry (Fig. 36) [162]. Firstly, the polymerization of sCL was initiated by a diol bearing an alkyne function. The chain-ends were protected from any further undesired reaction by the esterification reaction with acetyl chloride. The alkyne was then reacted with 3-azidopropan-l-ol. The hydroxyl function located at the middle of the chain was then used to initiate the ROP of sCL and y-bromo-s-caprolactone. Finally, pendant bromides were reacted successfully with sodium azide and then with N, N-dimethylprop-2-yn-l-amine to obtain pendant amines. Under acidic conditions, pendant amines were protonated and the polymer turned out to exhibit amphiphilic properties. 

Riva R, Schmeits S, Jerome C, Jerome R, Lecomte P (2007) Combination of ring-opening polymerization and click chemistry toward functionalization and grafting of poly( -caprolactone). Macromolecules 40 796-803... 

The modification of polymers can be readily conducted by chemical coupling reactions when the chain to be modified possesses groups such as vinyl, hydroxyl, or azide [23], etc. The Diels-Alder reaction between a diene and a dienophile, discovered by Otto Diels and Kurt Alder in 1928 [24], is the most important example of click chemistry. These robust and efficient click coupling reactions have been widely exploited in the construction of tailor-made functional polymeric materials with complex molecular architectures... 

Ladmiral V, Legge TM, Zhao Y, Perrier S (2008) Click chemistry and radical polymerization potential loss of orthogonality. Macromolecules 41 6728... 

X. Pang, L. Zhao, C. Feng, Z. Lin, Novel Amphiphilic Multiarm, Starhke Coil-Rod Diblock Copolymers via a Combination of Click Chemistry with Living Polymerization. Macromolecules 2011,44,7176-7183. 

Among these reactions, the Cu(l)-catalyzed azide-alkyne cycloaddition (CuAAC) is the most widely used. This reaction has been implemented for the preparation of segmented block copolymers from polymerizable monomers by different mechanisms. For example, Opsteen and van Hest [22] successfully prepared poly(ethylene oxide)-b-poly(methyl methacrylate) (PEO-b-PMMA) and PEO-b-PSt by using azide and alkyne end-functionalized homopolymers as the click reaction components (Scheme 11.2). Here, PEO, PSt, and PMMA homopolymers were obtained via living anionic ring-opening polymerization (AROP), atom transfer radical polymerization (ATRP), and postmodification reactions. Several research groups have demonstrated the combination of different polymerization techniques via CuAAC click chemistry, in the synthesis of poly(e-caprolactone)-b-poly(vinyl alcohol) (PCL-b-PVA)... 

This chapter will serve to highlight recent advances in polymer science that have been aided by the use of click chemistry. The copper(l)-catalyzed azide-alkyne cycloaddition (CuAAC) and thiol-ene reactions will be discussed first, after which the utilization of these chemical transformations in the construction and fimction-ahzation of a multitude of different polymeric materials will be outlined. Particular attention will be focused on the preparation of highly complex polymer architectures, such as dendrimers and star polymers, which exempHfy the essential role that chck chemistry has assumed in the polymer science community. 

Hyperbranched polymers can be prepared by a variety of techniques, including the polycondensation of AB monomers as originally described by Flory [113], the reaction of A2 + B3 monomers, and self-condensing vinyl polymerization [139-141]. The first report [142] of using click chemistry in the synthesis of hyperbranched materials appeared at about the same time as the initial report for dendrimers prepared using CuAAC however, but much fewer examples have been reported that describe hyperbranched materials involving click chemistry. Nevertheless, these polymers represent an important class of materials, and both CuAAC [142-147] and thiol-ene [148] chemistry have found their way into the hyperbranched hterature. 

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