Polyquinoxaline polymers

High molecular weight polyquinoxaline polymers were prepared from 3,3, 4,4 -tetraamino-biphenyl that was reacted with aromatic bis(a-diketones) and/or ethynyl-substituted aromatic bis(a-diketones). The polymers contain 0, 5, 10, 30, and 100% pendant groups. Also, ethynyl-substituted diketones were synthesized by the following procedure ... 

Polyquinoxalines (PQ) have proven to be one of the better heat-resistant polymers with regard to both stabiUty and potential appHcation. The aromatic backbones are derived from the condensation of a tetramine with a bis-glyoxal, reactions first done in 1964 (61,62). In 1967, a soluble, phenylated version of this polymer was produced (63). The chemistry and technology of polyquinoxalines has been reviewed (64). 

Polymers such as PBI have a weak link in them since a single covalent bond connects the phenyl rings in biphenyl. This weakness is overcome by the synthesis of ladder polymers, such as polyquinoxaline structures 4.64 and 4.65, and polydithione (structure 4.66), which have two covalent bonds throughout the chain. Thus, the integrity of the polymer is maintained even if one bond is broken ... 

A number of thermally stable polymers have been synthesized, but in general the types of structures that impart thermal resistance also result in poor processing characteristics. Attempts to overcome this problem have largely been concentrated on the incorporation of flexible groups into the backbone or the attachment of stable pendent groups. Among the class of polymers claimed to be thermally stable only a few have achieved technological importance, some of which are polyamides, polyimides, polyquinoxalines, poly quinolines, and polybenzimidazoles. Of these, polyimides have been the most widely explored. 

Polymer poly 5,5-carbonylbis[1.3-tsobenzofurandione]-a/(-bis(3-ami nophenyl-methanone polyp role (20 wt % ) in carbon black dopped with an organic acid anion polyqutnolines and polyquinoxalines... 

Polydiaminophenazine, polyquinoxaline, polydiaminopyridine, polyphenothiazine as novel multifunctional polymers from aromatic diamines by oxidative polymerizations 02CRV2925. 

The area of chiral polymers is also a field of growing interest, with chiral structures reported for polymethacrylate esters and polyacetaldehydes, polytriha-loacetaldehydes, polythiophenes, polyquinoxalin-2,3-diyles, poly-arene-... 

Polyquinoxalines (11) are another group of ladder polymers. They differ from polyimidazopyrrolones by the presence of a fused six-membered cyclic diimide structure. A possible synthetic route for polyquinoxalines involves the reaction of 1,4,5,8-naphthalene tetracarboxylic acid with aromatic tetra-amines in polyphosphoric acid (PEA) at temperatures up to 220°C. 

If two tetrafunctional monomers are used, as in the formation of polyquinoxaline (PQ) from an aromatic tetramine and an aromatic tetraketone, the resulting polymer is a ladder polymer ... 

Other tetraketones have also been used in the preparation of PQs. The PQs have proven to be one of the better high temperature polymers with respect to both stability and potential application. The PQs are also one of the three most highly developed systems—the others being benzimidazoles and oxadiazoles. The interest in the PQs increased considerably after the development in 1967 of the soluble phenylated polyquinoxaline (PPQ). PQs are stable to 550°C and are used for high-temperature composites and adhesives. 

The above-described two-step processes yield polymers that evolve volatiles upon further heating because the condensations continue. To overcome this drawback, prepolymers were developed thatundeigo addition-type reactions at fairly moderate time-temperature schedules. Such prepolymers are terminated by functional groups. The following is an example of one such material, an oligomer, polyquinoxaline-terminated by acetylene groups ... 

As a result, extensive research has been underway for over two decades in search of structural adhesives which have the requisite balance of processability, properties and cost effectiveness. The most promising materials have been derived from polymers containing various aromatic and heteroaromatic rings including, among others, various polyimides, polybenzimidazoles and polyquinoxalines. 

Several processable, thermally stable polymers have been developed, e.g., polyimides (PI), polyimidesulfone, polyphenyIquinoxalines (PPQ) f polyquinoxalines (PQ), and polyimidesulfide hot melt (3), and triary1-s-1riazine ring,... 

Professor John K. Stille, one of the outstanding polymer chemists of our time, died on July 19, 1989, in the crash of the United Airlines flight in Sioux City, Iowa. John was educated as a polymer chemist in the illustrious school of G.S. Marval. In that tradition, ability to synthesize novel materials plays a major role. John more than lived up to that tradition. Particularly memorable is his extended work on the polyquinoxalines, important materials in the aerospace industry. Beyond these, he synthesized authentic poly-p-phenylene utilizing Diels-Alder reactions of pyrones, synthesized a new type of polyacetylene by cyclopolymerization, and studied numerous other novel polymers. 

Polyquinolines and polyquinoxalines are n-type (electron transporting) polymers and therefore offer alternative EL device engineering in conjunction with the extensively studied p-type (hole transporting) polymers such as poly(p-phe-nylene vinylene)s, polyphenylenes, and polythiophenes. A variety of polyquinolines [331,332] and polyquinoxalines [333] has been reported in the literature, acting as the active... 

Rigid rod ladder polymer, consisting of two parallel chains of polymer regularly joined by covalent bonding, viz., pyrrones, polyquinoxalines, and polyphenylsilsesquioxane. 

Polyquinoxaline is relatively stable in air at 310°C, but at 371°C severe oxidative degradation occurs. If the pyrazine hydrogen atoms (hydrogen next to nitrogen) are replaced by phenyl groups, the thermal stability increases dramatically hence, polyphenylquinoxa-line polymers are more stable than quinoxaline itself. 

The materials mostly used as ETLs are oxadiazole derivatives [177], which are evaporated or dispersed in the polymer matrix, polyquinoxaline derivatives [178], oxadiazole-based polymers [179], and so on [180]. Poly(9-vinylcarbazole) and PPV... 

Rabilloud, G., High Performance Polymers, Chemistry and Applications, Polyquinoxalines and Polyimides, vol. 2. Editions Technip, 1999. 

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