Polyaromatic polymers

Hollis, O.L., Separation of gaseous mixtures using porous polyaromatic polymer beads, Anal. Chem., 38, 309, 1966. 

Mechanical pulp contains approximately 20% m/m lignin, a coloured, random polyaromatic polymer. The objective of the bleaching operation is to destroy the chromophoric groups without substantial removal of the lignin. Mechanical pulp products are currently used for newsprint and packaging. 

O Dell [2,3] to prepare polyaromatic polymers, (IV) and (V), respectively, which were used in optoelectronic applications. 

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

Figure 11 Selected literature data for proton conductivity as a function of inverse temperature. Imidazole-intercalated sulfonated polyaromatic polymer (IISPAP) Ba2YSn05 5 (BYSO) Ba3Cai igNb 1.82O8.73 (BCN18), the curve for Y BaCe03 is a calculated estimate. The interpretation of the conductivity of Gd BaPr03 as protonic is somewhat ambiguous at present. For further explanation and discussion, see Ref 119. (Reprinted from Ref 119 1999, with permission from Elsevier)...

A significant number of efforts to prepare membranes of lower methanol permeability for use in DMFCs have been reported. The general types of new DMFC membrane preparations tried to date include (1) replacing poly(PFSA) by sufonated polyaromatic polymers [105],... 

The vast majority of renewable natural resources comprises materials that consist of several polymeric constituents (1-3). Wood is a multicomponent material composed of principally three polymers, a crystalline homopolysaccharide (cellulose), several types of branched, non-ordered heteropolysaccharides (hemicelluloses), and an apparently non-ordered polyaromatic polymer that shows network-like behavior (lignin) (4). While the chemistry of all three constituents is by and large well understood, the basis for the interaction of these three polymers is still subject to some conjecture (5,6). 

In this review, we discuss the electrode/electrochemical properties and technological applications of -conjugated polymers. It is organized by material and the matmals are grouped in two classes, the polyaromatic polymer films such as the polymer derivatives of aniline, pyrrole, and thiophene, and the linear polyenes such as polyacetylene, polythiazyl. The report does not intend to review the preparation procedures or the physical properties of these materials since they have been summarized elsewhere It is also limited to work published in the scientific literature without attempting to include the numerous patents which have appeared in the last few years. 

The materials discussed in this section are polyaromatic polymer/anion composite films prepared electrochemically by the polymerization of the derivatives of pyrrole, aniline, thiophene, azulene and benzene. The films are normally used directly as grown on the metal substrate where they have good adhesion and electrical contact. The switching properties of these materials are described with more detail in the first section which describes polyaniline. However, it should be understood that these characteristics are generally common to all of the materials. 

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-... 

As for most polyaromatic polymers, SPI membranes exhibit a low methanol crossover and these membranes were considered as promising ma-... 

It is now recognized that the introduction of aromatic or heteroaromatic rings as replacements for the olefinic structure leads to more-stahle conjugated polymCTs which may be exposed to air without fear of degradation. Examples of such polyaromatic polymers include polypyrrole, 5, polythiothene, 6, and polyaniline. 

As for most polyaromatic polymers, sPl membranes exhibit a low methanol crossover and these membranes were considered as promising materials for DMFCs [56,74,78,111]. However, it is difficult to hnd any data in the literature about the solvent uptake either in methanol or in water/methanol mixtures. In contrast to Nahon membranes, which exhibit a high affinity to methanol [118], pure methanol is obviously a poor solvent for sPl since it can be used to precipitate the polymer from... 

In the case of polyacetylene the total energy of the systems as function of the dimerisation amplitude (fig. 1) shows two equal minima as the results of the Peierls distortion which favours dimerisation [2]. If we consider the case of polyaromatic polymers for which the ground electronic state is not accidentally doubly degenerate (fig. 2) the coordinate Jl can be defined as the collective geometrical evolution of the network of double/single CC bonds in transforming from the "aromatic" ground state structure to the excited electronic state described as "quinoid" (fig.2)... 

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