Poly oxidative environments

Fare S, Petrini P, Motta A, Cigada A, Tanzi M. Synergistic effects of oxidative environments and mechanical stress on in vitro stability of poly(ether urethanes) and poly(carbonate urethanes). J Biomed Mater Res 1999 45(1) 62—74. 

Although of limited success, this Ni-catalysed coupling strategy builds on a previous report of the successful, direct synthesis of poly(4,4 -diphenylphenyl-phosphine oxide) (70c) from bis(p-chlorophenyl)-phenylphosphine oxide (71) (Scheme 21) [66]. The white soluble material (70c) (Aj ax 280 nm) was found to have a single phosphorus environment by NMR spectroscopy, a comparatively high molecular weight (Mn= 15,300) together with a low molecular... 

Braaz R, P Fischer, D Jendrossek (2004) Novel type of heme-dependent oxygenase catalyzes oxidative cleavage of rubber (poly-cw-l,4-isoprene). Appl Environ Microbiol 70 7388-7395. 

The synthesis of chalcogenides such as those of the rare earth elements has traditionally been performed through the reaction of rare earth metals or oxides with a molten or vaporous chalcogen source in a high-temperature environment. Soft synthetic methods utilizing lower temperature conditions, such as hydrothermal or flux syntheses, can allow access also to thermodynamically metastable phases. Flux syntheses of R chalcogenides via an alkali poly-chalcogenide flux have been shown to be extremely versatile for the preparation of many new structures, some of which cannot be obtained by direct synthesis from the elements. 

Wholly aromatic polymers are thought to be one of the more promising routes to high performance PEMs because of their availability, processability, wide variety of chemical compositions, and anticipated stability in the fuel cell environment. Specifically, poly(arylene ether) materials such as poly-(arylene ether ether ketone) (PEEK), poly(arylene ether sulfone), and their derivatives are the focus of many investigations, and the synthesis of these materials has been widely reported.This family of copolymers is attractive for use in PEMs because of their well-known oxidative and hydrolytic stability under harsh conditions and because many different chemical structures, including partially fluorinated materials, are possible, as shown in Figure 8. Introduction of active proton exchange sites to poly-(arylene ether) s has been accomplished by both a polymer postmodification approach and direct co-... 

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