Synthesis and properties of new soluble aromatic polybenzoxazoles from 4,4′-diamino-3,3′-dihydroxytriphenylamines and aromatic dicarboxylic acids

Two new triphenylamine-based bis (o-aminophenol) monomers, 4,4′-diamino-3,3′-dihydroxytriphenylamines, were successfully synthesized by the cesium fluoride-mediated condensation of 2-(benzyloxy)-4-fluoronitrobenzene with aniline derivatives, followed by simultaneous deprotection and reduction. Aromatic polybenzoxazoles having inherent viscosities of 0.58–1.05 dL/g were obtained by the low-temperature solution polycondensation of the bis(aminophenol)s with various aromatic dicarboxylic acid chlorides and the subsequent thermal cyclodehydration of the resultant poly(hydroxyamide)s. All the polybenzoxazoles were amorphous, and most of them were soluble in organic solvents such as m-cresol and o-chlorophenol. Flexible and tough films of polybenzoxazoles could be cast from the DMAc solutions of some aromatic poly(hydroxyamide)s, followed by thermal cyclodehydration. The glass transition temperatures and 10% weight loss temperatures of the polybenzoxazoles under nitrogen were in the range of 262–327 and 610–640°C, respectively. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1987–1994, 1998     

Preparation and properties of aromatic polyamides from 2,2′-bis(p-aminophenoxy) biphenyl or 2,2′-bis(p-aminophenoxy)-1,1′-binaphthyl and aromatic dicarboxylic acids

New aromatic diamines having kink and crank structures, 2,2′-bis(p-aminophenoxy)biphenyl and 2,2′-bis(p-aminophenoxy)-1,1′-binaphthyl, were synthesized by the reaction of p-fluoronitrobenzene with biphenyl-2,2′-diol and 2,2′-dihydroxy-1,1′-binaphthyl, respectively, followed by catalytic reduction. Biphenyl-2,2′-diyl- and 1,1′-binaphthyl-2,2′-diyl-containing aromatic polyamides having inherent viscosities of 0.44–1.18 and 0.26–0.88 dL/g, respectively, were obtained either by the direct polycondensation or low-temperature solution polycondensation of the diamines with aromatic dicarboxylic acids (or diacid chlorides). These polymers were readily soluble in a variety of organic solvents including N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide, m-cresol, and pyridine. Transparent, pale yellow, and flexible films of these polymers could be cast from the DMAc or NMP solutions. These aromatic polyamides containing biphenyl and binaphthyl units had glass transition temperatures in the range of 215–255 and 266–303°C, respectively. They began to lose weight at ca. 380°C, with 10% weight loss being recorded at about 470°C in air. © 1993 John Wiley & Sons, Inc.     

Synthesis and characterization of soluble aromatic polyurea-amides from new N,N′--dimethyl-N,N′-bis(aminophenyl)ureas and aromatic dicarboxylic acid chlorides

Aromatic polyurea-amides having inherent viscosities of 0.36–0.67 dL/g were synthesized by the low temperature solution polycondensation of new N,N′-dimethyl-N,N′-bis(aminophenyl)ureas with various aromatic dicarboxylic acid chlorides. All the polymers were amorphous, and most of them were soluble in a variety of organic solvents such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide (DMAc), m-cresol, and pyridine. Some of the polymers could be cast from the DMAc solutions into transparent and flexible films having good tensile properties. The glass transition temperatures of the polyurea-amides obtained from the bis(4-aminophenyl)-substituted ureas were 244–272°C. The temperatures of 10% weight loss under nitrogen of the polymers were in the range of 430 and 480°C. © 1995 John Wiley & Sons, Inc.     

Synthesis and characterization of poly(arylene ether)s derived from 4,4′‐bishydroxybiphenyl and 4,4′‐bishydroxyterphenyl

A series of poly(arylene ether)s were successfully prepared by aromatic, nucleophilic substitution reactions with various perfluoroalkyl‐activated bisfluoromonomers with 4,4′‐bishydroxybiphenyl and 4,4′‐bishydroxyterphenyl. 4,4′‐Bishydroxyterphenyl was synthesized through the Grignard coupling reaction of magnesium salt of 4‐bromoanisole with dibromobenzene followed by demethylation with pyridine–hydrochloride. The products obtained by the displacement of fluorine atoms exhibited good inherent viscosity, up to 0.77 dL/g, and number‐average molecular weights up to 69,300. These poly(arylene ether)s showed very good thermal stability, up to 548 °C for 5% weight loss according to thermogravimetric analysis under synthetic air, and high glass‐transition temperatures, up to 259 °C according to differential scanning calorimetry, depending on the exact repeat unit structure. These polymers were soluble in a wide range of organic solvents, such as N‐methylpyrrolidone, dimethylformamide, tetrahydrofuran, toluene, and CHCl₃, and were insoluble in dimethyl sulfoxide and acetone. Thin films of these poly(arylene ether)s showed good transparency and exhibited tensile strengths up to 132 MPa, moduli up to 3.34 GPa, and elongations at break up to 84%, depending on their exact repeating unit structures. These values are comparable to those of high‐performance thermoplastic materials such as poly(ether ether ketone) (PEEK) and Ultem poly(ether imide) (PEI). These poly(arylene ether)s exhibited low dielectric constants. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 55–69, 2002     

Synthesis and characterization of novel soluble triphenylamine‐containing aromatic polyamides based on N,N′‐bis(4‐aminophenyl)‐N,N′‐diphenyl‐1,4‐phenylenediamine

A new triphenylamine‐containing aromatic diamine, N, N′‐bis(4‐aminophenyl)‐N, N′‐diphenyl‐1,4‐phenylenediamine, was prepared by the condensation of N,N′‐diphenyl‐1,4‐phenylenediamine with 4‐fluoronitrobenzene, followed by catalytic reduction. A series of novel aromatic polyamides with triphenylamine units were prepared from the diamine and various aromatic dicarboxylic acids or their diacid chlorides via the direct phosphorylation polycondensation or low‐temperature solution polycondensation. All the polyamides were amorphous and readily soluble in many organic solvents such as N, N‐dimethylacetamide and N‐methyl‐2‐pyrrolidone. These polymers could be solution cast into transparent, tough, and flexible films with good mechanical properties. They had useful levels of thermal stability associated with relatively high glass‐transition temperatures (257–287 °C), 10% weight‐loss temperatures in excess of 550 °C, and char yields at 800 °C in nitrogen higher than 72%. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2810–2818, 2002     

Synthesis and properties of aromatic polyamides based on 4,4′-(2,7-naphthalenedioxy)dibenzoic acid

4,4′-(2,7-Naphthalenedioxy)dibenzoic acid, a new aromatic dicarboxylic acid monomer, was prepared starting from 2,7-dihydroxynaphthalene and p-fluorobenzonitrile in three steps. Using triphenyl phosphite (TPP) and pyridine as condensing agents, a series of novel aromatic polyamides were synthesized by the direct polycondensation of the diacid monomer and aromatic diamines in N-methyl-2-pyrrolidone (NMP) solution containing dissolved calcium chloride. The resulting polyamides had inherent viscosities ranging from 0.48 to 0.67 dL/g. Most of these polyamides were readily soluble in polar solvents, such as NMP and N,N-dimethylacetamide (DMAc). Transparent, flexible, and tough films were cast from their DMAc solutions. They had tensile strengths of 65–70 MPa, elongations to break of 5–7%, and initial moduli of 1.4–1.6 GPa. Most of these polymers proved to be amorphous, with glass transition temperatures in the range between 143–227°C. Thermogravimetric analysis (TG) showed that all the polyamides were stable up to 450°C in both air and nitrogen atmospheres. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1469–1478, 1997     

LC polyimides. XXXVI. Poly(ester imide)s derived from N,N′‐Bis(4‐hydroxyphenyl)biphenyl‐3,3′,4,4′‐tetracarboxylic diimide and aliphatic dicarboxylic acids

A new mesogenic monomer was prepared from biphenyl‐3,3′,4,4′‐tetracarboxylic dianhydride and 4‐aminophenol followed by the acylation of OH groups with propionic anhydride. This diphenol propionate was polycondensed by transesterification with decane‐1,10‐dicarboxylic acid, dodecane‐1,12‐dicarboxylic acid, and eicosane‐1,20‐dicarboxylic acid or with equimolar mixtures of two dicarboxylic acids. The resulting poly(ester imide)s were characterized by elemental analyses, ¹H NMR spectra, inherent viscosities, DSC measurements, optical microscopy, and X‐ray measurements with synchrotron radiation at variable temperatures. An enantiotropic smectic A phase in the molten state and a crystalline smectic E (or H) phase in the solid state were found in all cases. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3019–3027, 2000     

Synthesis and characterization of novel,optically active poly(amide‐imide)s from N,N′‐(4,4′‐sulfonediphthaloyl)‐bis‐L‐phenylalanine diacid chloride and aromatic diamines under microwave irradiation

3,3′,4,4′‐Diphenylsulfonetetracarboxylic dianhydride was reacted with L ‐phenylalanine in acetic acid, and the resulting imide acid ( 3 ) was obtained in high yield. The diacid chloride ( 4 ) was obtained from its diacid derivative ( 3 ) by reaction with thionyl chloride. The polycondensation reaction of 4 with several aromatic diamines such as 4,4′‐sulfonyldianiline, 4,4′‐diaminodiphenyl methane, 4,4′‐diaminodiphenylether, p‐phenylenediamine, m‐phenylenediamine, 2,4‐diaminotoluene, and 1,5‐diaminonaphthalene was developed with a domestic microwave oven in the presence of trimethylsilyl chloride and a small amount of a polar organic medium such as o‐cresol. The polymerization reactions were also performed with two other methods: low‐temperature solution polycondensation in the presence of trimethylsilyl chloride and reflux conditions. A series of optically active poly(amide‐imide)s with moderate inherent viscosities of 0.21–0.42 dL/g were obtained in high yield. All of the aforementioned polymers were fully characterized by IR, ¹H NMR elemental analyses, and specific rotation techniques. Some structural characterizations and physical properties of these optically active poly(amide‐imide) s are reported. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3974–3988, 2003     

Synthesis of optically active poly(amide‐imide)s derived from N,N′‐(4,4′‐carbonyldiphthaloyl)‐bis‐L‐leucine diacid chloride and aromatic diamines by microwave radiation

3,3′,4,4′‐benzophenonetetracarboxylic dianhydride (4,4′‐carbonyldiphathalic anhydride) was reacted with L ‐leucine in a mixture of acetic acid and pyridine (3 : 2), and the resulting imide‐acid [N,N′‐(4,4′‐carbonyldiphthaloyl)‐bis‐L ‐leucine diacid] was obtained in quantitative yield. The compound was converted to the N,N′‐(4,4′‐carbonyldiphthaloyl)‐bis‐L ‐leucine diacid chloride by reaction with thionyl chloride. A new facile and rapid polycondensation reaction of this diacid chloride with several aromatic diamines such as 4,4′‐diaminodiphenyl methane, 2,4‐diaminotoluene, 4,4′‐sulfonyldianiline, p‐phenylenedi‐amine, 4,4′‐diaminodiphenylether, and m‐phenylenediamine was developed by using a domestic microwave oven in the presence of a small amount of a polar organic medium such as O‐cresol. The polymerization reactions proceeded rapidly compared with the conventional solution polycondensation and were completed within 6 min, producing a series of optically active poly(amide‐imide)s with a high yield and an inherent viscosity of 0.37–0.57 dL/g. All of the above polymers were fully characterized by IR, elemental analyses, and specific rotation. Some structural characterization and physical properties of these optically active poly(amide‐imide)s are reported. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 177–186, 2001     

Wholly aromatic thermotropic liquid crystalline polyesters of 3,3′-bis(phenyl)-4,4′-biphenol with 4,4′-benzophenone dicarboxylic acid

A series of wholly aromatic, thermotropic polyesters, derived from 3,3′-bis(phenyl)-4,4′-biphenol (DPBP), nonlinear 4,4′-benzophenone dicarboxylic acid (4,4′-BDA), and various linear comonomers, were prepared by the melt polycondensation reaction and characterized for their thermotropic properties by a variety of experimental techniques. The homopolymer of DPBP with 4,4′-BDA had a fusion temperature (T_f) at 265°C, exhibited a nematic phase, and had a liquid crystalline range of 105°C. All of the copolyesters of DPBP with 4,4′-BDA and either 30 mol % 4-hydroxybenzoic acid (HBA), 6-hydroxy-2-naphthoic acid (HNA), or 50 mol % terephthalic acid (TA), 2,6-naphthalenedicarboxylic acid (2,6-NDA) had low T_f values in the range of 220–285°C, exhibited a nematic phase, and had accessible isotropization transitions (T_i) in the range of 270–420°C, respectively. Their accessible T_i values would enable one to observe a biphase structure. Each of the copolymers with HBA or HNA had a much broader range of liquid crystalline phase. In contrast, each of the copolymers with TA or 2,6-NDA had a relatively narrow range of liquid crystalline phase. Each of these polyesters had a glassy, nematic morphology that was confirmed with the DSC, PLM, WAXD, and SEM studies. As expected, they had higher glass transition temperatures (T_g) in the range of 161–217°C than those of other liquid crystalline polyesters, and excellent thermal stabilities (T_d) in the range of 494–517°C, respectively. Despite their noncrystallinity, they were not soluble in common organic solvents with the exception that the homopolymer and its copolymer with TA had limited solubility in CHCl₃. However, they were soluble in the usual mixture of p-chlorophenol/1,1,2,2-tetrachloroethane (60/40 by weight) with the exception of the copolymer with 2,6-NDA. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 769–785, 1997     

Synthesis and properties of Ortho-linked aromatic polyamides based on 4,4′-(2,3-naphthalenedioxy) dibenzoic acid

A novel aromatic dicarboxylic acid monomer, 4,4′-(2,3-naphthalenedioxy)-dibenzoic acid ( 3 ), was prepared by the fluorodisplacement reaction of p-fluorobenzonitrile with 2,3-dihydroxynaphthalene in N,N-dimethylformamide (DMF) in the presence of potassium carbonate followed by alkaline hydrolysis of the intermediate dinitrile. A series of novel aromatic polyamides containing ortho-linked aromatic units in the main chain were synthesized by the direct polycondensation of diacid 3 and a variety of aromatic diamines using triphenyl phosphite and pyridine as condensing agents in the N-methyl-2-pyrrolidone (NMP) solution containing dissolved calcium chloride. The resulting polyamides had inherent viscosities higher than 0.74 and up to 2.10 dL/g. All of these polyamides were soluble in polar solvents, such as NMP, DMF, N,N-dimethylacetamide (DMAc), and dimethyl sulfoxide. Transparent, flexible, and tough films could be cast from their DMAc or NMP solutions. The solvent-cast films had high tensile strengths and moduli. Extensions to break were relatively low, except for the polymers derived from 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane and 3,4′-oxydianiline, which had elongations of 82 and 62%, respectively. Except for the polyamide based on p-phenylenediamine, all the other polyamides were amorphous in nature. All the polymers are thermally stable to temperatures in excess of 450°C in either air or nitrogen atmosphere. The polymers exhibited glass transition temperatures ranging from 183 to 260°C and decomposition temperatures (10% weight loss) ranging from 462–523°C in air and 468–530°C in nitrogen. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 3385–3391, 1997     

Synthesis and properties of soluble aromatic polyamides derived from 2,2′‐bis(4‐carboxyphenoxy)‐9,9′‐spirobifluorene

The synthesis of a new bis(ether carboxylic acid), 2,2′‐bis(4‐carboxyphenoxy)‐9,9′‐spirobifluorene, in which two orthogonally arranged carboxyphenoxyfluorene entities are connected through an sp³ carbon atom (the spiro center), is reported. The direct phosphorylation polycondensation of this diacid monomer with various aromatic diamines yields aromatic polyamides containing 9,9′‐spirobifluorene moieties in the main chain. The presence of the spiro segment restricts the close packing of the polymer chains and decreases interchain interactions, resulting in amorphous polyamides with enhanced solubility, and high glass‐transition temperatures and good thermal stability are maintained through controlled segmental mobility. The glass‐transition temperatures of these polyamides are in the range of 234–306 °C, with 10% weight losses occurring at temperatures above 530 °C. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1160–1166, 2003     

Polymerization of 4,4′‐(hexafluoroisopropylidene)‐N,N′‐bis(phthaloyl‐L‐leucine) diacid chloride with aromatic diamines by microwave irradiation

A new facile and rapid polycondensation reaction of 4,4′‐(hexafluoroisopropylidene)‐N,N′‐bis(phthaloyl‐L‐leucine) diacid chloride (1) with several aromatic diamines, including benzidine (2a), 4,4′‐diaminodiphenyl methane (2b), 1,5‐diaminoanthraquinone (2c), 4,4′‐sulfonyldianiline (2d), 3,3′‐diaminobenzophenone (2e), P‐phenylenediamine (2f), 2,6‐diaminopyridine (2g), 4,4′‐diaminobenzophenone (2h), 2,4‐diaminotoluene (2i), and 4,4′‐diaminodiphenylether (2j), was developed with a domestic microwave oven in the presence of a small amount of a polar organic medium such as o‐cresol. The polymerization reactions proceeded rapidly compared to conventional solution polycondensation and finished within 12 min, producing a series of optically active poly(amide‐imide)s with quantitative yields and high inherent viscosities of 0.50–1.93 dL/g. All of the polymers were fully characterized by IR, elemental analyses, and specific rotation. Some structural characterization and physical properties of these optically active poly(amide‐imide)s are reported. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1154–1160, 2000     

Synthesis and properties of aromatic polyamides derived from 1,6-bis(4-aminophenoxy)naphthalene and aromatic dicarboxylic acids

A new bis(phenoxy)naphthalene-containing diamine, 1,6-bis(4-aminophenoxy)naphthalene, was synthesized in two steps from the condensation of 1,6-dihydroxynaphthalene with p-chloronitrobenzene in the presence of potassium carbonate, giving 1,6-bis(4-nitrophenoxv)naphthalene, followed by hydrazine hydrate/Pd—C reduction. A series of polyamides were synthesized by the direct polycondensation of the diamine with various aromatic dicarboxylic acids in the N-methyl-2-pyrrolidone (NMP) solution containing dissolved metal salts such as CaCl₂ or LiBr using triphenyl phosphite and pyridine as condensing agents. The polymers were obtained in quantitative yield with inherent viscosities of 0.78–3.72 dL/g. Most of the polymers were soluble in aprotic solvents such as N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), NMP, and they could be solution-cast into transparent, flexible and tough films. The casting films had tensile strength of 102–175 MPa, elongation at break of 8–42%, and tensile modulus of 2.4–3.8 GPa. The polymers derived from rigid dicarboxylic acids such as terephthalic acid and 4,4′-biphenyldicarboxylic acid exhibited some crystalline characteristics. The glass transition temperatures of the polyamides were in the range of 238–337°C, and their 10% weight loss temperatures were above 487°C in nitrogen and above 438°C in air. © 1995 John Wiley & Sons, Inc.     

Synthesis and properties of aromatic polyamides derived from 1,2-bis(4-aminophenoxy)benzene and aromatic dicarboxylic acids

1,2-Bis(4-aminophenoxy)benzene was synthesized in two steps by the preparation of 1,2-bis(4-itrophenoxy)benzene from 1,2-dihydroxybenzene (catechol) and p-chloronitrobenzene and subsequent reduction with a 10% Pd-C catalyst and hydrazine hydrate. Aromatic polyamides with an inherent viscosity in the range of 1.08–2.00 dL/g were prepared by the direct polycondensation of this diamine with various aromatic dicarboxylic acids in N-methyl-2-pyrrolidone (NMP) using triphenyl phosphite and pyridine as condensing agents. Most of the polymers formed were soluble in aprotic solvents such as NMP and N,N-methylacetamide (DMAc), and afforded transparent, flexible, and tough films upon casting from DMAc solutions. Most of the cast films showed obvious yield points in their stress-strain curves and had tensile strength among 64–89 MPa, elongation at break among 5–23%, and initial modulus in 1.7–2.5 GPa. The glass transition temperatures (T_g) of these polymers were in the range of 207–278°C, and the 10% weight loss temperatures were recorded above 475°C in nitrogen and above 452°C in air. © 1995 John Wiley & Sons, Inc.     

Synthesis and properties of aromatic polyamides based on non-, methyl-, and phenyl-substituted 4,4′-bis(1,4-phenylenedioxy)dibenzoic acids

4,4′-(1,4-Phenylenedioxy)dibenzoic acid (3), 4,4′-(2,5-tolylenedioxy)dibenzoic acid (Me-3), and 4,4′-(2,5-biphenylenedioxy)dibenzoic acid (Ph-3) were prepared by the nucleophilic substitution reaction of p-fluorobenzonitrile with hydroquinone, methylhydroquinone, and phenylhydroquinone, respectively, followed by alkaline hydrolysis. Several aromatic polyamides having inherent viscosities of 0.66–1.34 dL/g were directly prepared by a Yamazaki phosphorylation polyamidation technique from dicarboxylic acids 3, Me-3, and Ph-3, respectively, with aromatic diamines using triphenyl phosphite and pyridine as condensing agents. The solubility of methyl- or phenyl-substituted polyamides was remarkably enhanced when compared to that of nonsubstituted analogues. Most of the substituted polyamides revealed an amorphous nature and were readily soluble in a variety of organic solvents including N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), N,N-dimethylformamide, dimethyl sulfoxide, and m-cresol. Transparent, flexible, and tough films of these polymers could be cast from the DMAc or NMP solutions. These films had tensile strength of 60–100 MPa, elongation to break of 6–11%, and tensile modulus of 1.68–2.25 GPa. The glass transition temperatures (T_g) of most polyamides could be determined by differential scanning calorimetry (DSC) and were in the range of 200–232°C. Thermogravimetric analyses established that these polymers were fairly stable up to 450°C, and the 10% weight loss temperatures were recorded in the range of 458–535°C in nitrogen and 468–528°C in air atmosphere. In general, the phenyl-substituted polyamides exhibited relatively higher T_g, thermal stability, and solubility. © 1996 John Wiley & Sons, Inc.     

Synthesis and properties of new soluble aromatic polyamides and polyimides on the basis of N,N′‐bis(3‐aminobenzoyl)‐N,N′‐diphenyl‐1,4‐phenylenediamine

A new N‐phenylated amide (N‐phenylamide) unit containing aromatic diamine, N,N′‐bis(3‐aminobenzoyl)‐N,N′‐diphenyl‐1,4‐phenylenediamine, was prepared by the condensation of N,N′‐diphenyl‐1,4‐phenylenediamine with 3‐nitrobenzoyl chloride, followed by catalytic reduction. Two series of organosoluble aromatic poly(N‐phenylamide‐imide)s and poly(N‐phenylamide‐amide)s with inherent viscosities of 0.58–0.82 and 0.56–1.21 dL/g were prepared by a conventional two‐stage method and the direct phosphorylation polycondensation, respectively, from the diamine with various aromatic dianhydrides and aromatic dicarboxylic acids. All polyimides and polyamides are amorphous and readily soluble in many organic solvents such as N,N‐dimethylacetamide and N‐methyl‐2‐pyrrolidone. These polymers could be solution cast into transparent, tough, and flexible films with high tensile strengths. These polyimides and polyamides had glass‐transition temperatures in the ranges of 230–258 and 196–229 °C, respectively. Decomposition temperatures of the polyimides for 10% weight loss all occurred above 500 °C in both nitrogen and air atmospheres. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2564–2574, 2002     

Blue‐light‐emitting and anodically electrochromic materials of new wholly aromatic polyamides derived from the high‐efficiency chromophore 4,4′‐dicarboxy‐4″‐methyltriphenylamine

A series of organosoluble, aromatic polyamides were synthesized from a 4‐methyl‐substituted, triphenylamine‐containing, aromatic diacid monomer, 4,4′‐dicarboxy‐4″‐methyltriphenylamine, which is a blue‐light (454‐nm) emitter with a fluorescence quantum efficiency of 46%. These triphenylamine‐based, high‐performance polymers had strong fluorescence emissions in the blue region with high quantum yields up to 64% and one reversible oxidation redox couple around 1.20 V versus Ag/AgCl in acetonitrile solutions. They exhibited good thermal stability, with 10% weight loss temperatures above 480 °C under a nitrogen atmosphere and with relatively high glass‐transition temperatures (252–309 °C). All the polyamides revealed excellent stability of electrochromic characteristics, changing color from the original pale yellow to blue. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4095–4107, 2006