N. M. Belomoina

Heterocyclic polyamides with pendent imide groups

New poly(phenylquinoxaline-amide)s and poly(phenylquinoxaline-imide-amide)s containing pendent phthalimide or 3,4,5,6-tctrachlorphthalimide groups have been synthesized by low-temperature solution polycondensation of diaminophenylquinoxalines with diacid chlorides of two aromatic acids containing preformed imide ridgs. The inherent viscosity, solubility, thermal stability, glass transition tempratures, dielectric constants and mechanical properties of these polymers have been studied.

Highly phenylated polyarylenes: Synthesis, properties, and applications

The syntheses of highly phenylated polyarylenes (polyphenylenes, polyalkylenephenylenes, poly(phenylene oxides), poly(phenylene sulfides), poly(phenylene ketones), and poly(phenylene ethynylenes)) based on the interaction of hexaphenyl-substituted bis(cyclopentadienes) of the appropriate structure with diethynylarylenes via the Dields-Alder reaction are considered. Polymers containing no less than six phenyl substituents per repeating unit and characterized by the isomerism of backbone chains combine unique solubility in common organic solvents with excellent thermal characteristics. Highly phenylated polyarylenes are of interest as materials for electronics, microelectronics, membrane techniques, and fuel cells.

New Synthetic Approach to the Preparation of Polyphenyleneethynylenes and Polyheteroaryleneethynylenes

Polyphenyleneethynylenes and polyheteroaryleneethynylenes—polymers with promising electro-optical properties—are usually prepared by the interaction of dihaloaromatic and diethynylaromatic compounds catalysed with transition metal (first of all, Pd) derivatives. Because of the side reactions these procedures often lead to the formation of relatively low molecular weight polymers; inaddition, preparationoforgano-solublepolyphenyleneethynylenes and polyheteroaryleneethynylenes seems to be rather problematic. In the framework of the present investigation we have developed a new synthetic approach to the preparation of polyphenyleneethynylenes and polyheteroaryleneethynylenes. This approach is based on the utilization of acetylene-containing monomers (e.g. bis-α-diketones, bis-cyclopentadienones and diacetylenearylenes) in smoothly-proceeding polymer-forming reactions (the formation of polyphenylquinoxalines and phenylated polyphenylenes). This approach leads to the preparation of high molecular weight polyphenyleneethynylenes and polyphenylquinoxalineethynylenes combining solubility in organic solvents with film-forming properties.

Fluorinated Poly(Phenylquinoxaline–Imide–Amide)S

Poly(phenylquinoxaline–imide–amide)s have been synthesized by solution polycondensation of aromatic diamines containing preformed phenylquinoxaline rings with a diacid chloride incorporating preformed imide rings and hexafluoroisopropylidene (6F) groups. These polymers do not decompose up to 400 °C and have glass transition temperatures in the range of 284–308 °C. They are soluble in polar amidic solvents, such as N-methyl-pyrrolidone, and in less polar solvents such as pyridine and tetrahydrofuran, and give flexible films by casting from solutions.

Ionomers of a new type based on sulfonated polyphenylquinoxalines

This communication is devoted to new type iono mers belonging to the class of aromatic ionogenic polymers—sulfonated polyphenylquinoxalines (SPPQ). The interest in SPPQ is due to the fact that the parent polyphenylquinoxalines (PPQ) are promising poly heteroarylenes combining high thermal characteristics and chemical stability with excellent solubility in organic solvents and good film forming properties [7]. Therefore, SPPQ formed upon polymer analogous transformation of PPQ upon sulfonation with a mix ture of sulfuric acid and oleum [8] can be considered as potential effective thermally stable polymeric elec trolytes and as the basis for the production of promis ing thermally stable aromatic ionomers for various applications.

Poly(naphthoylenebenzimidazole)s with Trifluoromethyl and Phenyl Substituents

129 Poly(naphthoylenebenzimidazole)s (PNBIs) is one of the most important classes of thermostable polymers with a combination of unique properties: thermal stability; heat, fire, and chemical resistance; high hydrolytic and radiation stability; etc. [1–3]. However, the application of these polymers is limited by their insolubility in organic solvents and, hence, poor processability. Therefore, attempts have been made in recent years to introduce flexible fragments or bulky substituents into polymeric chains to impart sol ubility to PNBIs [4, 5].

Sulfonated poly(naphthoylenebenzimidazole) and its modification with an alkali metal cation

A method for sulfonation of poly(naphthoylenebenzimidazole) with oleum–sulfuric acid mixture to produce sulfonated poly(naphthoylenebenzimidazole)s (SPNBIs) with different content of–SO3H groups has been developed. SPNBIs containing ≥5% sulfur are soluble in NMP and form stable solutions. It has been revealed that viscosity of SPNBI solutions in NMP increases on decreasing concentration when the content of polar sulfonic groups enhances with sulfonation degree of the initial polymer. Thus, SPNBI shows the polyelectrolyte effect. The substitution of hydrogen atoms in sulfonic groups by an alkali metal ion, potassium, has been conducted by the treatment of SPNBI powders with 5 M KOH aqueous solution under heterogeneous conditions. Potassium salts of SPNBI are insoluble in NMP. The introduction of potassium ions into SPNBI leads to the preparation of ionomers with a thermal stability higher than that of the initial PNBI.

Novel electron-withdrawing π-conjugated pyrene-containing poly(phenylquinoxaline)s

65 In recent time, conjugated polymers have attracted considerable attention of researchers not only from scientific but also from a practical viewpoint due to their fundamental optoelectronic properties and application as electroactive materials for organic light emitting diodes [1], field effect transistors [2], and photovoltaic devices [3]. Conjugated polymers are prepared by Stille, Suzuki, and Yamamoto reactions using nickel (Yamamoto) and palladium (Suzuki and Stille) catalysts [4, 5]. However, the high cost of the processes and difficulties of purification from metal catalyst residues, which are undesirable impurities for optoelectronic devices, are considerable drawbacks of these reactions. New noncatalytic methods for the synthesis of high purity conjugated polymers should be developed to solve these problems. It has also been found that intense electroluminescence and high charge mobility in a polymer require a high electron– hole conduction of a medium due to charge carriers mobility and a balance of injection of carriers of both signs from opposite electrodes into the emission poly mer layer. However, the majority of conjugated poly mers provide hole transport that causes imbalance of charge injection and a poor quantum yield. The search for new efficient electron transport polymers is necessary to improve the characteristics of electrooptical devices, which is provided, in particu lar, by the introduction of electron withdrawing frag ments—triazole [6], oxodiazole [7], quinoline [8], and quinoxaline [9]—into macromolecules. The lat ter are the least studied and show higher electron withdrawing properties due to the presence of four electron withdrawing heteroatoms. π Conjugated thiophene containing poly(phenylquinoxaline)s (PPQs) have been obtained recently. These PPQs behave as excellent electron transport materials for organic light emitting diodes [10]. We prepared new conjugated pyrene containing PPQs as high purity polymers by noncatalytic polycondensation reaction to provide the balance of the hole and electron con duction. The introduction of flat structures, such as pyrene, into a conjugated polymer is supposed to enhance intermolecular electronic interaction in the solid state and result in formation of π–π stacking structures. In continuation of our studies [11, 12], we prepared and studied new bipolar pyrene containing PPQs as efficient electron hole and transport materi als and thereby synthesized, previously unknown bis(α diketone)s IV and VIII.

Thermostable and Heat Resistant Aromatic Polyethers Based on Heterocyclic Bisphenols

Recent achievements in the synthesis of polyethers based on bisphenols containing various heterocyclic (azole, benzazole, azine, benzazine, imide) and high-condensed groups are surveyed. The best results are obtained when polyethers are prepared via aromatic nucleophilic substitution reactions involving activated carbocyclic difluoroaromatic compounds as comonomers of heterocyclic bisphenols. Special attention is given to new polymer-forming coupling reactions giving rise to N-C bonds.

Modified Phenylquinoxaline-Containing Polymers and Materials on Their Basis

The latest data concerning the modification of polymers containing phenylquinoxaline cycles and the manufacture of polymer materials on their basis are systematized. It has been shown that the design of silicon-and fluorine-containing and sulfated poly(phenylquinoxalines) makes it possible to significantly improve the processability of polymers and the performance characteristics of the related materials.