Polyaromatic polymers oxidation

Polyaromatic phosphine oxide, (VI), and diamines, (Vll), were prepared by Towns [4] and coupled with fluorene derivatives, (Vlll), to produce the corresponding polyaromatic polymers. 

A second group of polyaromatic polymers have also been studied These include poly(phenylene vinylene) (15), which may be considered an acetylene copolymer, and its derivatives these polymers are dopable to conductivities up to 3 s/cmj Poly(2,5-thienyltye) (16) yields a conductivity of 10 s/cm with iodine Recently poly(N-methyl-3,3 -carbazolyl (17) was synthesized and upon treatment with iodine yielded a conductivity of 1 s/cm. Polymers (18) containing phenylene and sulfur nitride linkages are able to yield relatively high conductivities upon oxidation ... 

During the last ten years, many research results have shown that oxidative polymerization catalyzed by peroxidases is a convenient, resource-saving, and environmentally friendly method for synthesizing phenol polymers. In contrast to the conventional synthesis of phenol-formaldehyde resins, the peroxidase-catalyzed polymerization of phenol proceeds under mild reaction conditions (room temperature, neutral pH). The polymerization of toxic phenols has promising potential for the cleaning of wastewaters. Moreover, the polymerization of phenols from renewable resources is expected to attract much attention in times of worldwide demand for the replacement of petroleum-derived raw materials. Besides the environment-protecting aspects of this innovative type of polymerization, the enzyme-catalyzed polymerization represents a convenient method to reahze new types of functional polyaromatic polymers. Phenol polymers made by peroxidase catalysis should have much potential for electronic and optical apphcations. The synthesis of functional phenol polymers is facihtated by the fact that poly-... 

Chemically modified electrodes (CMEs) for electrocatalytic oxidation of the reduced form of the nicotinamide adenine dinucleotide cofactor (NADH) are discussed. The work of the authors in the field is reviewed. CMEs based on adsorbed polyaromatic redox mediators (phenoxazines and phenothiazines) and the deposition of aqueous insoluble redox polymers are described. 

In a mixture of water and water-miscible solvents such as acetone, 1,4-dioxane, and methanol, peroxidase could act as catalyst for oxidative polymerization of various phenol derivatives, yielding a new class of polyaromatics.4 The polymerization proceeds at room temperature, and during the polymerization, powdery polymers are often precipitated, which are readily collected after the polymerization. 

Commercial polymers based on the principle of synthesis of polyaromatic compounds include the previously discussed commercial polymers—aromatic polyamides, polyimides, polyfphenylene oxide), polysulfone, and polybenzimidazole (see Chapter 4). 

The other hpid polymer, suberin, is a heteropolymer, consisting of an aliphatic polyester associated with cross-linked polyaromatics and embedded waxes. Upon transesterification of suberin, the monomers released include C16-C28 m-hydroxy fatty acids and C16-C26 ct, -dicarboxyhc acids, the latter of which are diagnostic monomers, unsubstituted very-long-chain fatty acids (VLCFAs C>i8) and alcohols, glycerol and ferulate. Usually the major components of suberin are -hydroxy derivatives of palmitic and/or oleic acids, but in some cases oo-hydroxy C220 also is a dominant component [37]. Dicarboxylic FAs derived from further oxidation of the -hydroxy-FAs are also found in suberin. 

The electrochemical reactions which produce polyaromatic compounds from the monomer have stoichiometries in the range of 2-2.5 Faraday/mole of monomer. The stoichiometry for the formation of the polymer chain is 2 for large chain lengths, plus the charge associated with reversible oxidation of the polymer (0 to 0.5). The latter quantity varies with the individual monomer system, with the anion which is inserted upon oxidation of the polymer, and with the solvent and other components of the electrolyte medium. Anion content and degree of oxidation of various polymer films is presented in Table 2.2. 

These highly condensed polyaromatic supports do indeed prove to have much better thermo-oxidative stability than vinyl polymer supports (see... 

It is a support for acidic catalytic species which react with the oxidized products formed via the thermooxidative degradation of the material. So, the intumescent material consists of polyaromatic stacks bridged by polymer links and phosphate (poly-, di- or orthophosphate) groups, as presented in Figure 5. 

In a fire, zinc borate on its own forms a vitreous mass on the polymer surface providing a barrier between the flame and the source of support. In antimony- or halogen-based systems it helps formation of Sb-O-Cl groups, extinguishing the flame and suppressing fumes while promoting formation of polyaromatic structures. The Borax material has until now been used mainly for total (or more recently, partial (40-75%)) replacement of the more expensive antimony oxide in PVC, polyolefins, nylons, and elastomers. 

Simultaneous and sequential IPNs based on various polymeric systems have been prepared using polydimethylsiloxane (PDMS) as the host network (3-8). These systems include poly(ether-urethane), polystyrene, poly(2,6-dimethyl-1,4-phenyleneoxide), polyacrylic acid, PDMS, polymethylmethacrylate, polyethylene oxide (PEO)... as the guest network. Some semi-interpenetrating networks (s-IPNs) based either on a linear polymer embedded in a polysiloxane network (5,9,10) or on a linear polysiloxane combined with a PEO network (8) have also been described. In some cases, PDMS has been replaced by polyaromatic siloxanes such as polydiphenyl or polymethylphenylsiloxanes (10-12). The focus of this paper concerns the preparation and properties of IPNs and s-IPNs based on polysiloxanes and poly(diethyleneglycol bis-allylcarbonate) (13,14). 

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