Synthesis and properties of soluble aromatic polyimides from 2,2′-bis(3,4-dicarboxyphenoxy)-1,1′-binaphthyl dianhydride and aromatic diamines

Aromatic tetracarboxylic dianhydride having crank and twisted noncoplanar structure, 2,2′-bis(3,4-dicarboxyphenoxy)-1,1′-binaphthyl dianhydride, was synthesized by the reaction of 4-nitrophthalonitrile with 2,2′-dihydroxy-1,1′-binaphthyl, followed by alkaline hydrolysis of the intermediate bis(ether dinitrile) and subsequent dehydration of the resulting bis(ether diacid). Binaphthyl-2,2′-diyl–containing novel aromatic polyimides having inherent viscosities up to 0.67 dL/g were obtained by the one-step polymerization process starting from the bis(ether anhydride) and various aromatic diamines. All the polyimides showed typical amorphous diffraction patterns. Most of the polyimides were readily soluble in common organic solvents such as N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), and pyridine. These aromatic polyimides had glass transition temperatures in the range of 280–350°C, depending on the nature of the diamine moiety. All polymers were stable up to 400°C, with 10% weight loss being recorded above 485°C in air. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1937–1943, 1998     

New organo‐soluble aromatic polyimides based on 3,3′,5,5′‐tetrabromo‐2,2‐bis[4‐(3,4‐dicarboxyphenoxy)phenyl]propane dianhydride and aromatic diamines

New aromatic tetracarboxylic dianhydride, having isopropylidene and bromo‐substituted arylene ether structure 3,3′,5,5′‐tetrabromo‐2,2‐bis[4‐(3,4‐dicarboxyphenoxy)phenyl]propane dianhydride, was synthesized by the reaction of 4‐nitrophthalonitrile with 3,3′,5,5′‐tetrabromobisphenol A, followed by alkaline hydrolysis of the intermediate bis(ether dinitrile) and subsequent dehydration of the resulting bis(ether diacid). The novel aromatic polyetherimides having inherent viscosities up to 1.04 dL g⁻¹ were obtained by either a one‐step or a conventional two‐step polymerization process starting from the bis(ether anhydride) and various aromatic diamines. All the polyimides showed typical amorphous diffraction patterns. Most of the polyimides were readily soluble in common organic solvents such as N,N‐dimethylacetamide (DMAc), N‐methyl‐2‐pyrrolidone (NMP), pyridine, and even in less polar solvents like chloroform and tetrahydrofuran (THF). These aromatic polyimides had glass transition temperatures in the range of 256–303°C, depending on the nature of the diamine moiety. Thermogravimetric analysis (TGA) showed that all polymers were stable, with 10% weight loss recorded above 470°C in nitrogen. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1673–1680, 1999     

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.     

Preparation and properties of aromatic polyamides from 2,2′-bis(p-carboxyphenoxy) biphenyl or 2,2′-bis(p-carboxyphenoxy)-1,1′-binaphthyl and aromatic diamines

New aromatic dicarboxylic acids having kink and crank structures, 2,2′-bis(p-carboxyphenoxy) biphenyl and 2,2′-bis(p-carboxyphenoxy)-1,1′-binaphthyl, were synthesized by the reaction of p-fluorobenzonitrile with biphenyl-2,2′-diol and 2,2′-dihydroxy-1,1′-binaphthyl, respectively, followed by hydrolysis. Biphenyl-2,2′-diyl-and 1,1′-binaphthyl-2,2′-diyl-containing aromatic polyamides having inherent viscosities of 0.58–1.46 dL/g and 0.63–1.30 dL/g, respectively, were obtained by the low-temperature solution polycondensation of the corresponding diacid chlorides with aromatic diamines. 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 210–272 and 260–315°C, respectively. They began to lose weight around 380°C, with 10% weight loss being recorded at about 450°C in air. © 1993 John Wiley & Sons, Inc.     

Synthesis and characterization of optically active aromatic polyimides derived from 2,2′-bis(2-trifluoro- 4-aminophenoxy)-1,1′-binaphthyl and aromatic tetracarboxylic dianhydrides

Optically active 2,2′-bis(2-trifluoro-4-aminophenoxy)-1,1′-binaphthyl and its corresponding racemate were prepared by a nucleophilic substitution reaction of 1,1′-bi-2-naphthol with 2-chloro-5-nitrotrifluorotoluene and subsequently by the reduction of the resulting dinitro compounds. A series of optically active and optically inactive aromatic polyimides also were prepared therefrom. These polymers readily were soluble in common organic solvents such as pyridine, N,N′-dimethylacetamide, and m-cresol and had glass-transition temperatures of 256 ∼ 278 °C. The specific rotations of the chiral polymers ranged from 167 ∼ 258°, and their chiroptical properties also were studied. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 4536–4540, 1999     

Preparation and properties of aromatic polyimides from 2,2′-bis(p-aminophenoxy)biphenyl or 2,2′-bis)p-aminophenoxy)-1,1′-binaphthyl and aromatic tetracarboxylic dianhydrides

New aromatic polyimides containing a biphenyl-2,2′-diyl or 1,1′-binaphthyl-2,2′-diyl unit were prepared by a conventional two-step method starting from 2,2′-bis(p-aminophenoxy) biphenyl or 2,2′-bis(p-aminophenoxy)-1,1′-binaphthyl and aromatic tetracarboxylic dianhydrides. The polyimides having inherent viscosities of 0.69–0.99 and 0.51–0.59 dL/g, respectively, were obtained. Some of these polymers were readily soluble in a variety of organic solvents including N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide, and pyridine. Transparent, flexible, and pale yellow to brown films of these polymers could be cast from the DMAc or NMP polyamic acid solutions. These aromatic polyimides containing biphenyl and binaphthyl units had glass transition temperatures in the range of 200–235 and 286–358°C, respectively. They began to lose weight around 380°C, with 10% weight loss being recorded at about 470°C in air. © 1993 John Wiley & Sons, Inc.     

Preparation and properties of new soluble aromatic polyimides from 2,2′-bis(3,4-dicarboxyphenoxy)biphenyl dianhydride and aromatic diamines

A new aromatic tetracarboxylic dianhydride having a crank and twisted noncoplannar structure, 2,2′-bis(3,4-dicarboxyphenoxy)biphenyl dianhydride, was synthesized by the reaction of 4-nitrophthalonitrile with biphenyl-2,2′-diol, followed by hydrolysis and cyclodehydration. The biphenyl-2,2′-diyl-containing aromatic polyimides having inherent viscosities up to 0.66 dL/g were obtained by the conventional two-step procedure starting from the dianhydride monomer and various aromatic diamines. Most of the polyimides were readily soluble in amide-type solvents such as N,N-dimethylacetamide and N-methyl-2-pyrrolidone. The aromatic polyimides had glass transition temperatures in the range of 205–242°C, and began to lose weight around 415°C, with 10% weight loss being recorded at about 500°C in air. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2021–2027, 1998     

Synthesis and properties of poly(amide-imide)s based on the diimide-diacid condensed from 2,2′- bis(4-aminophenoxy)biphenyl and trimellitic anhydride

A new dicarboxylic acid having a kinked structure was synthesized from the condensation of 2,2′-bis(4-aminophenoxy)biphenyl and trimellitic anhydride. A series of biphenyl-2,2′-diyl-containing aromatic poly(amide-imide)s having inherent viscosities of 0.23–0.94 dL/g was prepared by the triphenyl phosphite activated polycondensation from the diimide-diacid II with various aromatic diamines in a medium consisting of N-methyl-2-pyrrolidone (NMP), pyridine, and calcium chloride. Most of the resulting polymers showed an amorphous nature and were readily soluble in a variety of organic solvents including NMP and N,N-dimethylacetamide (DMAc). Transparent, flexible, and tough films of these polymers could be cast from DMAc or NMP solutions. The glass transition temperatures of these polymers were in the range of 227–261°C and the 10% weight loss temperatures were above 520°C in nitrogen. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1169–1177, 1998     

Optically active poly(amide–imide)s containing axially dissymmetric 1,1′-binaphthyl moieties

Novel optically active aromatic poly(amide–imide)s (PAIs) were prepared from newly synthesized 2,2′-bis(3,4-dicarboxybenzamido)-1,1′-binaphthyl dianhydride ((+ )-, (S)-, and (R)-BNDADA). PAIs based on dianhydride monomers with different ee % were investigated with respect to their structures and chiroptical properties. These polymers were highly soluble in polar aprotic solvents such as N,N-dimethylacetamide, N-methyl-2-pyrrolidone, pyridine, etc., and showed high glass transition temperatures of 287–290°C and 5% weight loss temperatures of 450–465°C in nitrogen. Optically active PAIs exhibited high specific rotations, excellent optical stabilities, and a dependence of optical activities on temperature. Investigations on chiroptical properties indicated that chiral conformation was possessed by optically active PAIs. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3147–3154, 1999     

Preparation and properties of polyarylates both from 2,2′-bibenzoyl chloride and bisphenols and from biphenyl-2,2′-diol and aromatic dicarboxylic acid chlorides

Polyarylates having inherent viscosities up to 1.02 dL/g were synthesized both by the phase-transfer catalyzed two-phase polycondensation of 2,2′-bibenzoyl chloride with various bisphenols and by the high-temperature solution polycondensation of biphenyl-2,2′-diol with aromatic dicarboxylic acid chlorides. All the polyarylates were amorphous and soluble in a variety of organic solvents including N,N-dimethylformamide, N-methyl–2-pyrrolidone, chloroform, m-cresol, and pyridine. Transparent and flexible films of these polymers could be cast from the chloroform solutions. These polyarylates had glass transition temperatures in the range of 120–250°C and began to lose weight at around 380°C in air. © 1992 John Wiley & Sons, Inc.     

Synthesis and characterization of new soluble polyamides derived from 3,3′,5,5′-tetramethyl-2,2-bis[4-(4-carboxyphenoxy)phenyl]propane

A series of new soluble polyamides having isopropylidene and methyl-substituted arylene ether moieties in the polymer chain were prepared by the direct polycondensation of 3,3′,5,5′-tetramethyl-2,2-bis[4-(4-carboxyphenoxy)phenyl]propane and various diamines in N-methyl-2-pyrrolidinone (NMP) containing CaCl₂ using triphenyl phosphite and pyridine as condensing agents. Polymers were produced with moderate to high inherent viscosities of 0.85–1.47 dL g⁻¹ while the weight-average molecular weight and number-average molecular weight were in the range of 86,700–259,000 and 43,300–119,000, respectively. All the polymers were readily dissolved in polar aprotic solvents such as NMP, N,N-dimethylacetamide, and N,N-dimethylformamide, as well as less polar solvents such as m-cresol and pyridine, and even soluble in tetrahydrofuran. These polymers were solution-cast into transparent, flexible and tough films. All of the polymers were amorphous and the polyamide films had a tensile strength range of 82–122 MPa, an elongation at break range of 6–18%, and a tensile modulus range of 2.0–2.8 GPa. These polyamides had glass transition temperatures between 233–260°C and 10% weight loss temperatures in the range of 450–489 and 459–493°C in nitrogen and air atmosphere, respectively. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1997–2003, 1999     

Synthesis and properties of optically active aromatic polyimides derived from optically pure 1,1′-bi-2-naphthol

A series of new optically active aromatic polyimides containing axially dissymmetric 1,1′-binaphthalene-2,2-diyl units were prepared from optically pure (R)-(+)- or(S)-(−)-2,2′-bis(3,4-dicarboxyphenoxy)-1,1′-binaphthalene dianhydrides and various aromatic diamines via a conventional two-step procedure that included ring-opening polycondensation and chemical cyclodehydration. The optically pure isomer of dianhydride was prepared by a nucleophilic substitution of optically pure (R)-(+)- or(S)-(−)-1,1′-bi-2-naphthol with 4-nitrophthalonitrile in aprotic polar solvent and subsequent hydrolysis of the resultant tetranitrile derivatives, followed by the dehydration of the corresponding tetracarboxylic acids to obtain the dianhydrides. These polymers were readily soluble in common organic solvents such as N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and m-cresol, etc., and have glass transition temperatures of 251–296°C, and 5% weight loss occurs not lower than 480°C. The specific rotations of the optically active polyimides ranged from +196° to +263°, and the optical stability and chiroptical properties of them were also studied. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3287–3297, 1997     

Synthesis and properties of new soluble N-phenyl–substituted aromatic-aliphatic and all aromatic polyamides derived from 4,4′-dianilinobiphenyl

New N-phenylated aromatic-aliphatic and all aromatic polyamides were prepared by the high-temperature solution polycondensation of 4,4′-dianilinobiphenyl with both aliphatic (methylene chain lengths of 6–11) and aromatic dicarboxylic acid chlorides. All of the aromatic-aliphatic polyamides and the wholly aromatic polyamides exhibited an amorphous nature and good solubility in amide-type and chlorinated hydrocarbon solvents, except for those aromatic polyamides containing p-oriented phenylene or biphenylylene linkages in the backbone; the latter were crystalline and insoluble in organic solvents except m-cresol. The N-phenylated aromatic-aliphatic polyamides and aromatic polyamides had glass transition temperatures in the range of 79–116°C and 207–255°C, respectively, and all the polymers were thermally stable with decomposition temperatures above 400°C in air. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2193–2200, 1998     

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 chirooptical properties of optically active poly(ester imide)s based on axially asymmetric 1,1′‐binaphthyls

A series of optically active poly(ester imide)s (PEsI's) has been synthesized by the polycondensation reactions of new axially asymmetric dianhydrides, that is, (R)‐2,2′‐bis(3,4‐dicarboxybenzoyloxy)‐1,1′‐binaphthyl dianhydride and (S)‐2,2′‐bis(3,4‐dicarboxybenzoyloxy)‐1,1′‐binaphthyl dianhydride, and various diamines with aromatic, semiaromatic, and aliphatic structures. The polymers have inherent viscosities of 0.45–0.70 dL/g, very good solubility in common organic solvents, glass‐transition temperatures of 124–290 °C, and good thermal stability. Wide‐angle X‐ray crystallography of these polymers shows no crystal diffraction. In comparison with model compounds, an enhanced optical rotatory power has been observed for the repeat unit of optically active PEsI's based on aromatic diamines, and it has been attributed to a collaborative asymmetric perturbation of chiral 1,1′‐binaphthyls along the rigid backbones. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4318–4326, 2004     

Synthesis and properties of aromatic polyimides derived from 2,2,′3,3′‐biphenyltetracarboxylic dianhydride

2,2,′3,3′‐Biphenyltetracarboxylic dianhydride (2,2,′3,3′‐BPDA) was prepared by a coupling reaction of dimethyl 3‐iodophthalate. The X‐ray single‐crystal structure determination showed that this dianhydride had a bent and noncopolanar structure, presenting a striking contrast to its isomer, 3,3,′4,4′‐BPDA. This dianhydride was reacted with aromatic diamines in a polar aprotic solvent such as N,N‐dimethylacetamide (DMAc) to form polyamic acid intermediates, which imidized chemically to polyimides with inherent viscosities of 0.34–0.55 dL/g, depending on the diamine used. The polyimides from 2,2,′3,3′‐BPDA exhibited a good solubility and were dissolved in polar aprotic solvents and polychlorocarbons. These polyimides have high glass transition temperatures above 283°C. Thermogravimetric analyses indicated that these polyimides were fairly stable up to 500°C, and the 5% weight loss temperatures were recorded in the range of 534–583°C in nitrogen atmosphere and 537–561°C in air atmosphere. All polyimides were amorphous according to X‐ray determination. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1425–1433, 1999     

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     

Highly stable electrochromic polyamides based on N,N‐bis(4‐aminophenyl)‐N′,N′‐bis(4‐tert‐butylphenyl)‐1,4‐phenylenediamine

A new triphenylamine‐containing aromatic diamine monomer, N,N‐bis(4‐aminophenyl)‐N′,N′‐bis(4‐tert‐butylphenyl)‐1,4‐phenylenediamine, was synthesized by an established synthetic procedure from readily available reagents. A novel family of electroactive polyamides with di‐tert‐butyl‐substituted N,N,N′,N′‐tetraphenyl‐1,4‐phenylenediamine units were prepared via the phosphorylation polyamidation reactions of the newly synthesized diamine monomer with various aromatic or aliphatic dicarboxylic acids. All the polymers were amorphous with good solubility in many organic solvents, such as N‐methyl‐2‐pyrrolidinone (NMP) and N,N‐dimethylacetamide, and could be solution‐cast into tough and flexible polymer films. The polyamides derived from aromatic dicarboxylic acids had useful levels of thermal stability, with glass‐transition temperatures of 269–296 °C, 10% weight‐loss temperatures in excess of 544 °C, and char yields at 800 °C in nitrogen higher than 62%. The dilute solutions of these polyamides in NMP exhibited strong absorption bands centered at 316–342 nm and photoluminescence maxima around 362–465 nm in the violet‐blue region. The polyamides derived from aliphatic dicarboxylic acids were optically transparent in the visible region and fluoresced with a higher quantum yield compared with those derived from aromatic dicarboxylic acids. The hole‐transporting and electrochromic properties were examined by electrochemical and spectro‐electrochemical methods. Cyclic voltammograms of the polyamide films cast onto an indium‐tin oxide‐coated glass substrate exhibited two reversible oxidation redox couples at 0.57–0.60 V and 0.95–0.98 V versus Ag/AgCl in acetonitrile solution. The polyamide films revealed excellent elcterochemical and electrochromic stability, with a color change from a colorless or pale yellowish neutral form to green and blue oxidized forms at applied potentials ranging from 0.0 to 1.2 V. These anodically coloring polymeric materials showed interesting electrochromic properties, such as high coloration efficiency (CE = 216 cm²/C for the green coloring) and high contrast ratio of optical transmittance change (ΔT%) up to 64% at 424 nm and 59% at 983 nm for the green coloration, and 90% at 778 nm for the blue coloration. The electroactivity of the polymer remains intact even after cycling 500 times between its neutral and fully oxidized states. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2330–2343, 2009     

Synthesis and properties of noncoplanar rigid‐rod aromatic polyhydrazides and poly(1,3,4‐oxadiazole)s containing phenyl or naphthyl substituents

Two new phenyl‐ and naphthyl‐substituted rigid‐rod aromatic dicarboxylic acid monomers, 2,2′‐diphenylbiphenyl‐4,4′‐dicarboxylic acid ( 4 ) and 2,2′‐di(1‐naphthyl)biphenyl‐4,4′‐dicarboxylic acid ( 5 ), were synthesized by the Suzuki coupling reaction of 2,2′‐diiodobiphenyl‐4,4′‐dicarboxylic acid dimethyl ester with benzeneboronic acid and naphthaleneboronic acid, respectively, followed by alkaline hydrolysis of the ester groups. Four new polyhydrazides were prepared from the dicarboxylic acids 4 and 5 with terephthalic dihydrazide (TPH) and isophthalic dihydrazide (IPH), respectively, via the Yamazaki phosphorylation reaction. These polyhydrazides were amorphous and readily soluble in many organic solvents. Differential scanning calorimetry (DSC) indicated that these hydrazide polymers had glass transition temperatures in the range of 187–234 °C and could be thermally cyclodehydrated into the corresponding oxadiazole polymers in the range of 300–400 °C. The resulting poly(1,3,4‐oxadiazole)s exhibited T_g's in the range of 252–283 °C, 10% weight‐loss temperature in excess of 470 °C, and char yield at 800 °C in nitrogen higher than 54%. These organo‐soluble polyhydrazides and poly(1,3,4‐oxadiazole)s exhibited UV–Vis absorption maximum at 262–296 and 264–342 nm in NMP solution, and their photoluminescence spectra showed maximum bands around 414–445 and 404–453 nm, respectively, with quantum yield up to 38%. The electron‐transporting properties were examined by electrochemical methods. Cyclic voltammograms of the poly(1,3,4‐oxadiazole) films cast onto an indium‐tin oxide (ITO)‐coated glass substrate exhibited reversible reduction redox with E_onset at ?1.37 to ?1.57 V versus Ag/AgCl in dry N,N‐dimethylformamide solution. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6466–6483, 2006     

Syntheses and properties of organosoluble polyimides based on 5,5′‐bis[4‐(4‐aminophenoxy)phenyl]‐4, 7‐methanohexahydroindan

A series of organosoluble aromatic polyimides (PIs) was synthesized from 5,5′‐bis[4‐(4‐aminophenoxy)phenyl]‐4,7‐methanohexahydroindan (3) and commercial available aromatic dianhydrides such as 3,3′,4,4′‐biphenyltetracarboxylic dianhydride (BPDA), 4,4′‐oxydiphthalic anhydride (ODPA), 4,4′‐sulfonyl diphthalic anhydride (SDPA), or 2,2′‐bis(3,4‐dicarboxyphenyl) hexafluoropropanic dianhydride (6FDA). PIs (III_c–f), which were synthesized by direct polymerization in m‐cresol, had inherent viscosities of 0.83–1.05 dL/g. These polymers could easily be dissolved in N,N′‐dimethylacetamide (DMAc), N‐methyl‐2‐pyrrolidone (NMP), N,N‐dimethylformamide (DMF), pyridine, m‐cresol, and dichloromethane. Whereas copolymerization was proceeded with equivalent molar ratios of pyromellitic dianhydride (PMDA)/6FDA, 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride (BTDA)/6FDA, or BTDA/SDPA, or ½ for PMDA/SDPA, copolyimides (co‐PIs), derived from 3 and mixed dianhydrides, were soluble in NMP. All the soluble PIs could form transparent, flexible, and tough films, and they showed amorphous characteristics. These films had tensile strengths of 88–111 MPa, elongations at break of 5–10% and initial moduli of 2.01–2.67 GPa. The glass transition temperatures of these polymers were in the range of 252–311°C. Except for III_e, the 10% weight loss temperatures (T_d) of PIs were above 500°C, and the amount of carbonized residues of the PIs at 800°C in nitrogen atmosphere were above 50%. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1681–1691, 1999