Redox polymers synthesis

TABLE 9.3 Redox Polymer Synthesis Conditions and Resulting Measured Properties... 

GaUaway JW, Calabrese Barton SA. Effect of redox polymer synthesis on the performance of a mediated laccase oxygen cathode. J Electroanal Chem 2009 626 149-155. 

The first purposeful use of ATRA in polymer synthesis was in the production of telomers.26j In this early work, comparatively poor control over the polymerization was achieved and little attempt was made to explore the wider utility of the process. Some analogies may also be drawn with the work of Bamford et al, and others on transition metal/organic halide redox initiation (Sections 3.3,5.1 and 7.6.2).2M... 

The hydroxytelechelic polymers synthesis involving a free-radical mechanism employs polymerization initiators which are cleaved into free radicals bearing hydroxyl substituents, by heat, light or redox systems. These radicals initiate polymerization of monomers and can give hydroxyl-terminated polymers by recombination. 

Hydroxytelechelic polymer synthesis with redox systems requires hydrogen peroxide as an oxidizing agent and, generally, takes place in aqueous media (to solubilize the salts). This kind of polymerization is possible at lower temperatures compared to polymerizations initiated by thermal decomposition of H202. Therefore, the less frequent transfer reactions improve the polymer functionality and its polydispersity. 

Expertise in resin and polymer synthesis has made available materials which can function as solid, but insoluble, oxidizing or reducing agents they are sometimes called redox resins or electron exchangers . Their reactivity in the latter sense is due to the polymer matrix carrying functional groups which may be reversibly oxidized and reduced. Studies of these polymers have involved two main kinds of... 

J. A. Bmce, T. Murahashl, and M. S. Wrighton, Synthesis and characterization of structured interfaces for hydrogen generation. Study of an N, N -dialkyl-4, 4-bipyridinium redox polymer/palladium catalyst system, J. Phys. Chem. 86, 1552, 1982. 

Figure 5.11 Scheme for the synthesis of a pyridinylimidazolyl ligand, its copolymerization with acrylic acid (AA) and butyl acrylate (BA), and subsequent ligand substitution reaction with an osmium complex to yield a redox polymer. From [147] with permission from Elsevier. 

Redox catalyzed polymerizations using ferrous ion and peroxidative compound have been reported to be usefiil for grafting reaction of natural fiber such as chitosan (79). Ascorbic acid is also used instead of the ferrous ion 80). Ascorbic acid is reported to produce activated oxygen under mild condition, and recently it is used for linear polymer synthesis of sugar alcohol derivatives containing vinyl group 81). These catalysts, which promote the reaction under... 

Polymer Synthesis. Copolymers of alkylacrylamide (R) and acrylamide (AM), which we called RAM, were prepared with a micellar polymerization technique (4). A micellar surfactant solution was used to disperse the hydrophobic alkylacrylamide monomer into an aqueous phase that contained acrylamide. The monomers were polymerized with a standard free-radical initiator (e.g., potassium persulfate) or a redox initiator to yield the desired random copolymer. Varied temperature and initiator concentrations were used to provide polymers of different molecular weights. Polymerizations were taken to essentially complete conversion. Compositions, in terms of hydrophobe level reported in this chapter, were based on amounts charged to the reactor. Further details on the synthesis and structure of these RAM polymers... 

T.S. Vasilieva, S. Logvinov, A. Timonov, R. Amadelli, and D. Bartak, Electrochemical synthesis and characterization of redox polymer nanostructures, Langmuir, 19, 9005 9012 (2003). 

The synthesis of redox polymers is generally performed before deposition (124). First, a polymer is synthesized by condensation or addition polymerization with at least one monomer that is ledox-aclive. The polymer is immobilized on the substrate by dip-coating, drop-casting, or spin-coating. These procedures must be carefully applied if homogeneous and pinhole free films are needed. 

The redox polymers, POs-EA, was polyvinylpyridine partially N-complexed with [osmium bis(bipyridine) chloride]+ 2+ and quaternized with bromoethylamine. The synthesis followed the published procedures (i). The structure and the composition of POs-EA is shown in Fig. 1. The elemental analysis and UV-VIS spectroscopy showed that the repeating unit of the POs-EA had 1.1 ethylamine pendant functions and 1.8 unsubstituted pyridine rings per osmium complexed pyridine. 

The HRP-catalyzed polymerization of phenols was found to be a convenient way to produce redox polymers and conducting (electronically conducting and ionically conducting) polymers. Besides the interest in electronic conductive polyanilines [121], many efforts have been made to produce ionically conductive phenol polymers for battery applications. A classic effort is the synthesis of poly(hydroquinone) for use as a redox polymer. Typically, poly(quinone)s are prepared via chemical or electrochemical methodologies [122,123]. Both processes produce a large amount of by-products and lead to complex polymer structiues. The first alternative pathway to produce poly(hydroquinone) by peroxidase catalysis was based on a multienzymic... 

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