Living radical polymerization graft polymer

Comb or densely grafted polymers are defined as polymers that have at least one polymeric chains per monomer unit of the main chain, and Figure 29 shows examples obtained by metal-catalyzed living radical polymerization. Comb polymers possess physical properties similar to those of star polymers in solution. 

Davis, K.A., Matyjaszewski, K., 2002. Statistical, gradient, block, and graft copolymers by controlled/living radical polymerizations. Adv. Polym. Sci. 159, 1-169. 

A. Carreira, E. Gonsalves, P. Mendon( a, M. Gil, and J. Coelho, Temperature and pH responsive polymers based on chitosan applications and new graft copolymerization strategies based on living radical polymerization. Carbohydrate Polymers, 80 (3), 618-630, 2010. 

Many block and graft copolymer syntheses involving transformation reactions have been described. These involve preparation of polymeric species by a mechanism that leaves a terminal functionality that allows polymerization to be continued by another mechanism. Such processes are discussed in Section 7.6.2 for cases where one of the steps involves conventional radical polymerization. In this section, we consider cases where at least one of the steps involves living radical polymerization. Numerous examples of converting a preformed end-functional polymer to a macroinitiator for NMP or ATRP or a macro-RAFT agent have been reported.554 The overall process, when it involves RAFT polymerization, is shown in Scheme 9.60. 

Keywords Graft polymerization Living radical polymerization Polymer brush ... 

A dense polymer brush is obtained using the grafting from techniques. Surface-initiated polymerization in conjunction with a living polymerization technique is one of the most useful synthetic routes for the precise design and functionalization of the surfaces of various solid materials with well-defined polymers and copolymers. Above all, surface-initiated living radical polymerization (LRP) is particularly promising due to its simplicity and versatility and it has been applied for the synthesis of Au NPs. 

To synthesize graft copolymers by ATRP, the initiation site for living radical polymerization can be incorporated into the polymer chain. In general, copolymerization of olefins with functional monomers can be adopted for syntheses of PO macroinitiators. 

The metal-catalyzed copolymerization from carbon-halogen bonds in the main chain can be employed widely for graft polymer synthesis. A combination of nitroxide-mediated and copper-catalyzed living radical polymerizations, for example, gives graft copolymers G-6, where the main chain is prepared by the former.432 The chlorobenzyl unit in the copolymer is not active during the polymerization but, upon copper catalysis, it can initiate living radical polymerizations of styrene and methacrylates. 

A similar well-defined graft copolymer consisting of polystyrene main chain and branches (G-7) can be prepared simply via repetition of copper-catalyzed living radical polymerizations.209 Thus, the synthesis starts with the copolymerization of styrene and />(acetoxymethy 1)styrene or />(methoxymethyl)sty-rene, followed by bromination of the substituent into the benzyl bromide moiety, which then initiates the copper-catalyzed radical polymerization of styrene to give graft polymers with 8—14 branches. 

Polymer Grafting of Carbon Nanotubes by Con-trolled/Living Radical Polymerization Polymer grafting techniques that use direct covalent functionalization methods, such as radical reactions, have been developed in order to avoid the problems associated with the functionalization of CNTs using acids. These grafting techniques eliminate the need for nanotube pretreatment before the functionalization and allow attachment of polymer molecules to pristine tubes without altering their original structure. 

Davis KA, Matyjaszewski K. Statistical, Gradient, Block and Graft Copolymers by Controlled/Living Radical Polymerizations. Advances in Polymer Science. Berlin Springer 2002. 

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