High-molecular-weight poly p-phenylene

Recently, Ballard and co-workers discovered a novel path to prepare linear polyphenylene, based on the polymerization of derivatives of 5,6-dihydroxycyclohexa-1,3-diene. The advantage of this method is that the diene polymer remains soluble in a variety of solvents, because of the presence of solubilizing groups, such as ester functions. Because of this, molecular weight determinations can be made before the final pyrolysis to remove the attached groups. Ballard et al. reported that the final product is a high molecular weight poly(p-phenylene). 

Gagnon, D.R., et al. 1987. Synthesis, doping, and electrical conductivity of high molecular weight poly(p-phenylene vinylene). Polymer 28 567. 

The siloxy compound of cyclohexadiene is able to polymerize as shown in eq. (19.51). However, it is difficult to dehydrogenate the siloxy polymers by heating, but their acetoxy compounds are able to be dehydrogenated at 310-340 ""C to afford a high molecular weight poly-p-phenylene [95,95a]. 

Louwet, F, Vanderzande, D., Gelan, J., 1995. A general synthetic route to high-molecular-weight poly(p-xylylene)-derivatives—a new route to poly(p-phenylene vinylene). Synth. Met. 69, 509-510. 

L. Lutsen, P. Adriaensens, H. Becker, A.J. Van Breemen, D. Vanderzande, and J. Gelan, New synthesis of a soluble high molecular weight poly(arylene vinylene) poly[2-methoxy-5-(3,7-dimethyloctyloxy)-p-phenylene vinylene]. Polymerization and device properties, Macromolecules, 32 6517-6525, 1999. 

Silarylene-disiloxane polymers, which exhibit a wide range of physical properties depending on their composition and structure, have received considerable academic and industrial interest for nearly 50 years.One of the prominent properties of silarylene-disiloxane polymers is their excellent thermal stability. The typical methods employed for the synthesis of silarylene-siloxane polymers are the selfpolycondensation of arylenedisilanols or the copolycondensation of arylenedisila-nols with other bifunctional compounds. We found that the easily accessible 1,4-bis(dimethylsilyl)benzene (p-BSB) could react with water in the presence of a catalytic amount of transition metal (Pd, Pt, Rh, etc.) compounds at room temperature to afford high molecular weight poly[(oxydimethylsilylene)(l,4-phenylene) (dimethylsilylene)] with the evolution of H2 as the only by-product, as shown in Scheme 4.6. ... 

Poly(arylene vinylenes). The use of the soluble precursor route has been successful in the case of poly(arylene vinylenes), both those containing ben2enoid and heteroaromatic species as the aryl groups. The simplest member of this family is poly(p-phenylene vinylene) [26009-24-5] (PPV). High molecular weight PPV is prepared via a soluble precursor route (99—105). The method involves the synthesis of the bis-sulfonium salt from /)-dichloromethylbenzene, followed by a sodium hydroxide elimination polymerization reaction at 0°C to produce an aqueous solution of a polyelectrolyte precursor polymer (11). This polyelectrolyte is then processed into films, foams, and fibers, and converted to PPV thermally (eq. 8). 

Poly(naphthalene) is chemically similar to poly(p-phenylene), which is an insoluble, infusible, low-molecular-weight polymer, all attributes that preclude application in thin-film form in microelectronics. Although these materials possess several very desirable properties, such as high glass transition tempera-... 

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