Aromatic biphenylene polymers

HIGH MOLECULAR WEIGHT AROMATIC BIPHENYLENE POLYMERS BY NICKEL COUPLING OF ARYL DICHLORIDES... 

High Molecular Weight Aromatic Biphenylene Polymers by Nickel Coupling... 

In 1996, Wegner et al. published the synthesis of poly(oligophenylenevinyle-ne)s (96), consisting of biphenylene-, terphenylene- and quinquephenylene moieties as aromatic building blocks, via Suzuki-type aryl-aryl cross coupling of AA/BB-type monomers [121]. By judicious choice of the arylene moieties, the optical properties of the resulting polymers can be tailored within a wide range. 

In the presence of aromatic polymers, it reacts to form biphenylated aromatics as major products. Biphenylene end-capped polyimide oligomers were prepared using PMR technique and its curing poperties were investigated [88]. 

Solubilities. Rogers et al. (16-18) have prepared and reported on a large number of aromatic polyesters and polyamides containing the 2,2 -disubstituted 4,4 -biphenylene moiety. Some of the polymers were soluble in common solvents such as tetrahydrofuran and acetone, with solubility as high as 50% in one case. The solubilities of the amide monomers synthesized in this work are shown in Table I. These compounds exhibited virtually no solubility in common solvents such as acetone but displayed fairly high solubilities in several amide solvents, with and without added salts. Lyotropic liquid crystallinity was not observed although solubilities were as high as 40% (w/w) in some solvents. 

Table 23 demonstrates the mesogenicity of polymers containing biphenylene-S j -tetracarboxylic imide. A comparison of series 9 and 10 in the table shows that replacement of pyromellitic dianhydride with BPTA in a copolymer with two moles of m-aminophenol and an aromatic diacid does not lead to mesogenic polymers. The assignment of an MI score of 4 compared to 2 for pyromellitic anhydride does however raise the MI as far as the borderline condition of MI=9.5 when 2,6-naphthalene dicarboxylic acid is the co-monomer. 

Versions with diacid, diol and di-ester substituents have been patented [111] which are suitable for reacting into aromatic polyesters, as have stabilisers with suitable substituents to allow dispersion or dissolution in dye baths for impregnation into fibres or textiles [113,114,116]. Other related species include those with biphenylene groups on the 4- and 6-positions on the triazine core [119], naphthalene groups on 4 or on both 4 and 6 [120], 1,2,3,4-tetrahydronaphthalene on 4 and 6 [124], and 2-hydroxynaphthalene on the 2-position [125]. Versions with longer side chains than hexyl or octyl have also been synthesised, and it is claimed that these have increased compatibility with their host polymer [121, 127]. 

Polyquinolines represent another class of photocon-ductive 7r-conjugated rigid-rod polymers. High molecular weight polyquinolines (M 5 x 10 ) are prepared by an acid catalyzed reaction of aromatic o-amino ketones with keto methylene compounds [468,469]. Stolka and co-workers [470] recently reported on steady state photoconductivity measurements in poly(2,2 -(biphenylene)-6,6 -bis(4-phenyl quinoline)) (73b). In both polymers like in other conjugated polymers the low energy threshold of... 

Low MW polymer at 490°C produces benzene, phenol, benzaldehyde, 4-hydroxybenzaldehyde, diphenyl ether, biphenylene, benzophenone, series of -H, -OH and -CHO terminated chain fragments containing < 8 aromatic units and fragments containing dibenzo ran units. 

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