Polyphenylquinoxaline

Polyphenylquinoxaline has proven to be one of the better high-temperature polymers with respect to both high-temperature stability and processibility. This material was first prepared by Hergenrother and Levine 

---

Polyphenylquinoxalines (PPQ) are easier to make than the polyquinoxalines and offer superior solubiHty, processibiHty, and thermooxidative stabiHty (65). The PPQs exhibit excellent high temperature adhesive, composite, and film properties. However, to increase the use temperature of PPQs, acetylene... 

The newer open-ceU foams, based on polyimides (qv), polyben2imida2oles, polypyrones, polyureas, polyphenylquinoxalines, and phenoHc resins (qv), produce less smoke, are more fire resistant and can be used at higher temperatures. These materials are more expensive and used only for special appHcations including aircraft and marine vessels. Rigid poly(vinyl chloride) (PVC) foams are available in small quantities mainly for use in composite panels and piping appHcations (see Elame retardants Heat-RESISTANTPOLYA rs). 

Hyperbranched polyesters, 18, 32, 55-58 bulk synthesis of, 64 synthesis of, 114-118 Hyperbranched polyimides, 307-309 Hyperbranched polymers, 8-10, 348-350, 475-476, 481, 519-520 degree of branching in, 57 Hyperbranched polyphenylquinoxalines, 312-314... 

Y. Cui, X. Zhang, and S.A. Jenekhe, Thiophene-linked polyphenylquinoxaline a new electron transport conjugated polymer for electroluminescent devices, Macromolecules, 32 3824—3826,1999. 

The thermal stability of the polymer is an interesting criterion for one to develop because several authors have considered photoablation as proceeding through a purely thermal degradation. Polyimide and polyphenylquinoxaline, two polymers of the thermostable family, are stable up to a temperature of approximately 500. As seen in Figure 3a, they display quite... 

Figure 4. Deposited thickness measured with the microbalance as a function of ejection angle. Polyphenylquinoxaline at 248 nm, 200 mJ/cm2,600 pulses, pressure = 10-5 torr.

The authors thank Bernard Sillon for a gift of polyphenylquinoxaline and Jean Claude Wittmann for a gift of polyfbutylene terephthalate). 

Phenylquinoxalines - Polyphenylquinoxalines (PPQ) prepared from the reaction of aromatic bi s (o-di amines) and aromatic bis (phenyl-ot-diketones) are high temperature thermoplastics. They are process-able with little or no volatile evolution at relatively high temperatures (> 316°C) and pressure (-1.38 MPa) by virtue of their thermoplasticity. Like other thermoplastics, the processability is governed primarily by the chemical structure, molecular weight and molecular weight distribution. 

Polyphenylquinoxalines (PPQ) are obtained by the polymerization of aromatic bis-o-diamine and bis-a-ketoaldehyde reactants in m-cresol at 80°C [Hergenrother, 1988 Klein et al., 2001] ... 

The second synthetic route to PAE containing quinoxaline units involved the reaction of an aromatic dihydroxy quinoxaline or aromatic bis(hydroxy-quinoxaline) with activated aromatic difluoro compounds (Eq. (3)) [15]. The dihydroxy quinoxaline and bis(hydroxyquinoxaline) monomers were readily prepared from the condensation of 1,2-diaminobenzene with 4,4 -dihydroxyben-zil and aromatic bis(o-diamines) with 4-hydroxybenzil, respectively. The Tgs of a series of PAE containing quinoxaline units are presented in Tables 3 and 4. For these polymers, the trend for the Tg is sulfone > carbonyl > terephthaloyl-> isophthaloyl. This trend holds for most polymer families when polymers of similar molecular weights are compared. Several polyphenylquinoxalines of the same chemical structure as those in Table 3 were also prepared by the poly-... 

The model PBZT/ABPBI molecular composite system is limited since the rod and the matrix do not possess glass transition temperatures for subsequent post form consolidation. In an effort to improve the processability for molecular composites, thermoplastics were used as the host matrix. Processing from acidic solvents requires the thermoplastic host to be soluble and stable in meth-anesulfonic add. Thermoplastic matrices were investigated including both amorphous and semicrystalline nylons [71,72], polyphenylquinoxaline (PPQ) [73] and polyetheretherketone (PEEK) [74], Table 5 shows the mechanical properties obtained for various processed PBZT thermoplastic molecular composite systems. As an example, the PBZT/Nylon systems showed 50-300% improvement over uniaxially aligned chopped fiber composite of comparable compositions. However, the thermally-induced phase separation during consol-... 

BPA/DC was compounded with high-temperature resistant ladder and semi-ladder polymers. A composition, which contained BPA/DC, a polyimide resin, organic Zn salt and benzyldimethylamine in A -methylpyrrolidone solution was described. The binder was destined for the manufacture of copper clad laminates. Tg of the cross-linked material was 265 °C [50]. Another example is a binder obtained from BPA/DC and polyphenylquinoxaline in chloroform [51]. 

Fig. 48. Extended conformations of polyphenylquinoxaline molecules differing in the number of rotating bonds in the repeating unit I one bond II three bonds III four bonds...

Similar calculations of Sf and Af have been carried out for polyphenylquinoxalines ... 

Ballard Advanced Materials (BAM) ionomers are sulfonated copolymers of trifluorostyrene and substimted trifluorostyrene monomers. BAM, a subsidiary of Ballard Power Systems, investigated the conducting polymers based on polyphenylquinoxaline (PPQ). These can be sulfonated in a wide range and were referred to as BAMIG (Ballard first generation) membranes, but these membranes were found to have short durability. To overcome this problem, BAM developed a second generation of advanced membranes based on two distinct material types. The first material type consisted of a series of sulfonated poly(2,6-diphenyl 1,4-phenylene oxide). The second material type consisted of a series of sulfonated poly(arylether sulfone). But the durability of these membranes was also insufficient. Since the durability of previous membranes was limited, Ballard produced a novel family of sulfonated membranes based on a,p,p-ttifluorostyrene monomers and a series of substituted ttifluoro-comonomers... 

Polymerization of cyclic derivatives of carboxylic acids 81YGK723. Polyphenylquinoxalines 84MI3. 

Broad melting points of bis(phenylquinoxalylnaphthalic anhydrides) follow from the fact that these products are mixtures of isomers. This is typical for the formation of bis- and polyphenylquinoxaline systems [130-132]. 

TABLE 21 Characteristics of macromolecular coils of polyphenylquinoxaline, synthesized with differentcontentsofpoly functional componentY.inN-methylpyrrolydone solution. 

A considerable amount of research has been carried out in recent years into the design of matrix materials for the next generation of supersonic civil transports and much of it has focused on amide, imide and related structures. Among resins studied are the polystyrylpyridine (PSP) family, the polyamide-imides, polyetherimides, polyetherketones, and for very high temperatures, the polyphenylquinoxalines, the polybenzimidazoles and the aromatic polyesters [50,51]. Some generalizations emerge [52] ... 

After a brief description of the fundanietitals of High Resolution Electron Energy Loss Spectroscopy (HREELS), its potentialities in elucidating chemical reactions at a metal-polymer interface are illustrated by the well-known case of alunuRium evaporated onto polyimide (PMDA-OOA). Then the diHkuldes (but also the new promises) in roudnely applying this new spectroscopy to any metal-polymer sysKm will be shown for the copper-polyphenylquinoxaline interface. 

In this paper, only the basic physical principles of the technique and its most frequent applications will be summarized, as a recent review has been dedicated to this subject. Then, the now well-known case of the study of the A 1-polyiinide (PMDA-ODA) interface will be illustrated, as an example of the already extensive and systematic study of aluminium reaction at different chemical sites. Finally, a first attempt to describe another category of interface, i.e. the copper-polyphenylquinoxaline (PPC one, will be presented. The study of such interface is interesting as copper is significantly less reactive than aluminium, PPQ does not contain any reactive oxygen site, and chemical reactions (if any) are expected to... 

---