Polyimides based on 2,5‐bis(4‐aminophenoxy)biphenyl

A diamine monomer II , 2,5‐bis(4‐aminophenoxy)biphenyl, was prepared through a nucleophilic substitution reaction of phenylhydroquinone and p‐chloronitrobenzene in the presence of potassium carbonate in N,N‐dimethylformamide, followed by catalytic reduction with hydrazine and Pd/C. A series of all‐aromatic, organosoluble polyimides bearing pendent phenyl groups were synthesized from the diamine with six kinds of commercial dianhydrides via a conventional two‐stage process. For improving solubility of polypyromellitimide, copolypyromellitimides with arbitrary solubilities were prepared from II and a pair of dianhydrides, which were mixed at certain molar ratios. These polymers showed good solubilities in N‐methyl‐2‐pyrrolidone and m‐cresol. The softening temperatures of these polyimides were recorded between 206 and 269 °C. Polymers had glass‐transition temperatures at 230–286 °C and 10% weight‐loss temperatures above 521 °C in air or nitrogen atmospheres. Their films had high tensile moduli and strengths. Excellent properties of these polyimides are attributed to the incorporation of the pendent phenyl group in diamine II . © 2002 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 429–438, 2002; DOI 10.1002/pola.10116     

Synthesis and characterization of new highly organosoluble poly(ether imide)s based on 3,3′,5,5′‐tetramethyl‐2,2‐bis[4‐(4‐dicarboxyphenoxy)phenyl]propane dianhydride

A new bis(ether anhydride), 3,3′,5,5′‐tetramethyl‐2,2‐bis[4‐(4‐dicarboxyphenoxy)phenyl]propane dianhydride ( 3 ), was prepared in three steps: the nitro displacement of 4‐nitrophthalonitrile with 2,2‐bis(4‐hydroxy‐3,5‐dimethylphenyl)propane, the alkaline hydrolysis of the intermediate bis(ether dinitrile), and the subsequent dehydration of the resulting bis(ether diacid). A series of new highly soluble poly(ether imide)s with tetramethyl and isopropylidene groups were prepared from the bis(ether anhydride) 3 with various diamines by a conventional two‐stage synthesis including polyaddition and chemical cyclodehydration. The resulting poly(ether imide)s had inherent viscosities of 0.54–0.73 dL g^?1. Gel permeation chromatography measurements revealed that the polymers had number‐average and weight‐average molecular weights of up to 54,000 and 124,000, respectively. All the polymers showed typical amorphous diffraction patterns. All of the poly(ether imide)s showed excellent solubility and were readily dissolved in various solvents such as N‐methyl‐2‐pyrrolidinone, N,N‐dimethylacetamide, N,N‐dimethylformamide, pyridine, cyclohexanone, tetrahydrofuran, and even chloroform. Most of the polymers could be dissolved with chloroform concentrations as high as 30 wt %. These polymers had glass‐transition temperatures of 244–282 °C. Thermogravimetric analysis showed that all polymers were stable, with 10% weight losses recorded above 463 °C in nitrogen. These transparent, tough, and flexible polymer films were obtained through solution casting from N,N‐dimethylacetamide solutions. These polymer films had tensile strengths of 81–102 MPa and tensile moduli of 1.8–2.0 GPa. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2556–2563, 2002     

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     

Synthesis and properties of soluble and light‐colored poly(amide‐imide‐imide)s on the basis of tetraimide‐dicarboxylic acid condensed from 4,4′‐oxydiphthalic anhydride, 2,2‐bis[4‐(4‐aminophenoxy)phenyl]propane,and m‐aminobenzoic acid,and various aromatic diamines

A new type of tetraimide‐dicarboxylic acid ( I ) was synthesized starting from the ring‐opening addition of m‐aminobenzoic acid, 4,4′‐oxydiphthalic anhydride, and 2,2‐bis[4‐(4‐aminophenoxy)phenyl]propane at a 2:2:1 molar ratio in N‐methyl‐2‐pyrrolidone (NMP), followed by cyclodehydration to the diacid I . A series of soluble and light‐colored poly(amide‐imide‐imide)s ( III _a–j) was prepared by triphenyl phosphite‐activated polycondensation from I with various aromatic diamines ( II _a–j). All films cast from N,N‐dimethylacetamide (DMAc) had cutoff wavelengths shorter than 390 nm (374–390 nm) and b* values between 25.26 and 43.61; these polymers were much lighter in color than the alternating trimellitimide series. All of the polymers were readily soluble in a variety of organic solvents such as NMP, DMAc, N,N‐dimethylformamide, dimethyl sulfoxide, and even in less polar m‐cresol and pyridine. Polymers III _a–j afforded tough, transparent, and flexible films that had tensile strengths ranging from 96 to 118 MPa, elongations at break from 9 to 11%, and initial moduli from 2.0 to 2.5 GPa. The glass‐transition temperatures of the polymers were recorded at 240–268 °C. They had 10% weight loss at a temperature above 540 °C and left more than 55% residue even at 800 °C in nitrogen. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 707–718, 2002; DOI 10.1002/pola.10153     

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     

Aromatic poly(1,3,4‐oxadiazole)s and poly(amide‐1,3,4‐oxadiazole)s containing ether sulfone linkages

Polyhydrazides and poly(amide‐hydrazide)s were prepared from two ether‐sulfone‐dicarboxylic acids, 4,4′‐[sulfonylbis(1,4‐phenylene)dioxy]dibenzoic acid and 4,4′‐[sulfonylbis(2,6‐dimethyl‐1,4‐phenylene)dioxy]dibenzoic acid, or their diacyl chlorides with terephthalic dihydrazide, isophthalic dihydrazide, and p‐aminobenzhydrazide via a phosphorylation reaction or a low‐temperature solution polycondensation. All the hydrazide polymers were found to be amorphous according to X‐ray diffraction analysis. They were readily soluble in polar organic solvents such as N‐methyl‐2‐pyrrolidone and N,N‐dimethylacetamide and could afford colorless, flexible, and tough films with good mechanical strengths via solvent casting. These hydrazide polymers exhibited glass‐transition temperatures of 149–207 °C and could be thermally cyclodehydrated into the corresponding oxadiazole polymers in the solid state at elevated temperatures. Although the oxadiazole polymers showed a significantly decreased solubility with respect to their hydrazide prepolymers, some oxadiazole polymers were still organosoluble. The thermally converted oxadiazole polymers had glass‐transition temperatures of 217–255 °C and softening temperatures of 215–268 °C and did not show significant weight loss before 400 °C in nitrogen or air. For a comparative study, related sulfonyl polymers without the ether groups were also synthesized from 4,4′‐sulfonyldibenzoic acid and the hydrazide monomers by the same synthetic routes. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2271–2286, 2001     

Synthesis and characterization of soluble polyimides derived from 2,2′‐Bis(3,4‐dicarboxyphenoxy)‐9,9′‐spirobifluorene dianhydride

The synthesis of aromatic poly(ether imide)s containing spirobifluorene units in the polymer backbone is described. 2,2′‐Bis(3,4‐dicarboxyphenoxy)‐9,9′‐spirobifluorene dianhydride, which was used as a new monomer, was synthesized with 2,2′‐dihydroxy‐9,9′‐spirobifluorene as the starting material. In the spiro‐segment, the rings of the connected bifluorene were orthogonally arranged. This bis(ether anhydride) monomer was employed in reactions with a variety of aromatic diamines to furnish poly(ether imide)s, involving an initial ring‐opening polycondensation and subsequent chemically induced cyclodehydration. Excellent solubility in common organic solvents at room temperature, good optical transparency, and high thermal stability are the prominent characteristic features of these new polymers, which can be attributed to the presence of spiro‐fused orthogonal bifluorene segments along the polymer chain. The glass‐transition temperatures of the polyimides were 240–293 °C, and the 5% weight‐loss temperatures were greater than 500 °C. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 262–268, 2002     

Synthesis and characterization of new highly organosoluble poly(etherimide)s derived from 1,1‐bis{4‐[4‐(3,4‐dicarboxyphenoxy)phenyl]‐4‐phenylcyclohexane} dianhydride

A new bulky pendent bis(ether anhydride), 1,1‐bis[4‐(4‐dicarboxyphenoxy)phenyl]‐4‐phenylcyclohexane dianhydride, was prepared in three steps, starting from the nitrodisplacement of 1,1‐bis(4‐hydroxyphenyl)‐4‐phenylcyclohexane with 4‐nitrophthalonitrile to form bis(ether dinitrile), followed by alkaline hydrolysis of the bis(ether dinitrile) and subsequent dehydration of the resulting bis(ether diacid). A series of new poly(ether imide)s were prepared from the bis(ether anhydride) with various diamines by a conventional two‐stage synthesis including polyaddition and subsequent chemical cyclodehydration. The resulting poly(ether imide)s had inherent viscosities of 0.50–0.73 dL g^?1. The gel permeation chromatography measurements revealed that the polymers had number‐average and weight‐average molecular weights of up to 57,000 and 130,000, respectively. All the polymers showed typical amorphous diffraction patterns. All of the poly(ether imide)s showed excellent solubility in comparison with the other polyimides derived from adamantane, norbornane, cyclododecane, and methanohexahydroindane and were readily dissolved in various solvents such as N‐methyl‐2‐pyrrolidinone, N,N‐dimethylacetamide (DMAc), N,N‐dimethylformamide, pyridine, cyclohexanone, tetrahydrofuran, and even chloroform. These polymers had glass‐transition temperatures of 226–255 °C. Most of the polymers could be dissolved in chloroform in as high as a 30 wt % concentration. Thermogravimetric analysis showed that all polymers were stable up to 450 °C, with 10% weight losses recorded from 458 to 497 °C in nitrogen. These transparent, tough, and flexible polymer films could be obtained by solution casting from DMAc solutions. These polymer films had tensile strengths of 79–103 MPa and tensile moduli of 1.5–2.1 GPa. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2066–2074, 2002     

Synthesis and characterization of new soluble poly(amide‐imide)s derived from 2,2‐bis[4‐(4‐trimellitimidophenoxy)phenyl]hexafluoropropane

A series of new soluble poly(amide‐imide)s were prepared from the diimide‐dicarboxylic acid 2,2‐bis[4‐(4‐trimellitimidophenoxy)phenyl]hexafluoropropane with various diamines by direct polycondensation in N‐methyl‐2‐pyrrolidinone containing CaCl₂ with triphenyl phosphite and pyridine as condensing agents. All the polymers were obtained in quantitative yields with inherent viscosities of 0.52–0.86 dL · g^?1. The poly(amide‐imide)s showed an amorphous nature and were readily soluble in various solvents, such as N‐methyl‐2‐pyrrolidinone, N,N‐dimethylacetamide (DMAc), N,N‐dimethylformamide, pyridine, and cyclohexanone. Tough and flexible films were obtained through casting from DMAc solutions. These polymer films had tensile strengths of 71–107 MPa and a tensile modulus range of 1.6–2.7 GPa. The glass‐transition temperatures of the polymers were determined by a differential scanning calorimetry method, and they ranged from 242 to 279 °C. These polymers were fairly stable up to a temperature around or above 400 °C, and they lost 10% of their weight from 480 to 536 °C and 486 to 537 °C in nitrogen and air, respectively. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3498–3504, 2001     

Synthesis and characterization of new organosoluble polyamides derived from bis[4‐(4‐carboxyphenoxy) phenyl]diphenylmethane

A new dicarboxylic acid containing a diphenylmethylene linkage, bis[4‐(4‐carboxyphenoxy)phenyl]diphenylmethane (BCAPD), was prepared from bis(4‐hydroxphenyl)diphenylmethane and p‐fluorobenzonitrile via an aromatic nucleophilic substitution reaction followed by hydrolysis. A series of novel polyamides were prepared by the direct polycondensation of BCAPD and various aromatic diamines. The polymers were produced with moderate to high inherent viscosities of 0.80–0.85 dL g^?1. Nearly all the polymers were readily soluble in polar solvents such as N‐methyl‐2‐pyrrolidinone, N,N‐dimethylacetamide, N,N‐dimethylformamide, and dimethyl sulfoxide, in less polar solvents such as pyridine and cyclohexanone, and in tetrahydrofuran. All the polymers were amorphous, and the polyamide films had a tensile strength and a tensile modulus greater than 80 MPa and 2.0 GPa, respectively. These polyamides had glass‐transition temperatures between 249 and 274 °C, and their temperatures at a 10% weight loss were 477–538 and 483–540 °C in nitrogen and air atmospheres, respectively. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1156–1161, 2001     

Synthesis and properties of new aromatic poly‐(ether benzoxazole)s from 2,2′‐bis(4‐amino‐3‐hydroxyphenoxy)biphenyl and aromatic dicarboxylic acid chlorides

A new bis(o‐aminophenol) with a crank and twisted noncoplanar structure and ether linkages, 2,2′‐bis(4‐amino‐3‐hydroxyphenoxy)biphenyl, was synthesized by the reaction of 2‐benzyloxy‐4‐fluoronitrobenzene with biphenyl‐2,2′‐diol, followed by reduction. Biphenyl‐2,2′‐diyl‐containing aromatic poly(ether benzoxazole)s with inherent viscosities of 0.52–1.01 dL/g were obtained by a conventional two‐step procedure involving the polycondensation of the bis(o‐aminophenol) monomer with various aromatic dicarboxylic acid chlorides, yielding precursor poly(ether o‐hydroxyamide)s, and subsequent thermal cyclodehydration. These new aromatic poly(ether benzoxazole)s were soluble in methanesulfonic acid, and some of them dissolved in m‐cresol. The aromatic poly(ether benzoxazole)s had glass‐transition temperatures of 190–251 °C and were stable up to 380 °C in nitrogen, with 10% weight losses being recorded above 520 °C. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2656–2662, 2002     

Synthesis and properties of new soluble triphenylamine‐based aromatic poly(amine amide)s derived from N,N′‐bis(4‐carboxyphenyl)‐N,N′‐diphenyl‐1,4‐phenylenediamine

A new triphenylamine‐containing aromatic dicarboxylic acid, N,N′‐bis(4‐carboxyphenyl)‐N,N′‐diphenyl‐1,4‐phenylenediamine, was synthesized by the condensation of N,N′‐diphenyl‐1,4‐phenylenediamine with 4‐fluorobenzonitrile, followed by the alkaline hydrolysis of the intermediate dinitrile compound. A series of novel triphenylamine‐based aromatic poly(amine amide)s with inherent viscosities of 0.50–1.02 dL/g were prepared from the diacid and various aromatic diamines by direct phosphorylation polycondensation. All the poly(amine amide)s were amorphous in nature, as evidenced by X‐ray diffractograms. Most of the poly(amine amide)s were quite soluble in a variety of organic solvents and could be solution‐cast into transparent, tough, and flexible films with good mechanical properties. They had useful levels of thermal stability associated with glass‐transition temperatures up to 280 °C, 10% weight‐loss temperatures in excess of 575 °C, and char yields at 800 °C in nitrogen higher than 60%. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 94–105, 2003     

Synthesis and functionalization of poly(ether sulfone)s based on 1,1,1‐tris(4‐hydroxyphenyl)ethane

Branched poly(ether sulfone)s were prepared from 1,1,1‐tris(4‐hydroxyphenyl) ethane and 4,4′‐difluorodiphenyl sulfone (DFDPS) either by polycondensation in dimethyl sulfoxide with the elimination of water or via the silyl method in N‐methylpyrrolidone. With an exact 1/1 stoichiometry, crosslinking was avoidable, but significant fractions of cyclic oligomers and polymers were detected by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. Furthermore, bridged cycles (bicycles) were detected. For the silyl method, even an excess of DFDPS of 10 mol % did not result in crosslinking. The pendant OH groups were modified by acylation with acetic anhydride, methacrylic anhydride, undecylenoyl chloride, or cinnamoyl chloride. Alkylation was only successful in a one‐pot procedure via the silyl method. Alkylbromide, ethyl bromoacetate, 3‐chloropropionitrile, 4‐nitrobenzyl bromide, and 3,4‐dichlorobenzyl chloride served as alkylating agents. With 1,3‐propane and 1,4‐butane sultone, poly(ether sulfone)s with pendant sulfonate groups were obtained. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2967–2978, 2002     

Soluble,redox‐active,and blue‐emitting poly(amide‐hydrazide)s and poly(amide‐1,3,4‐oxadiazole)s containing pyrenylamine units

Two new aromatic poly(amide‐hydrazide)s (PAHs)‐bearing electroactive pyrenylamine units in the backbone were prepared from the phosphorylation polycondensation reactions of N,N‐di(4‐carboxyphenyl)‐1‐aminopyrene ( 1 ) with p‐aminobenzoyl hydrazide (p‐ABH) and m‐aminobenzoyl hydrazide (m‐ABH), respectively. The PAHs could be further cyclodehydrated into the corresponding poly(amide‐1,3,4‐oxadiazole)s in the range of 300–400 °C in the solid film state. All the hydrazide and oxadiazole polymers were soluble in many polar organic solvents and could afford flexible and strong films via solution casting. The poly(amide‐1,3,4‐oxdiazole)s had high glass‐transition temperatures (294–309 °C) and high thermal stability (10% weight‐loss temperature in excess of 520 °C). The dilute solutions of all the hydrazide and oxadiazole polymers showed strong fluorescence with emission maxima around 457–459 nm in the blue region. Copolymers obtained from the polycondensation of equimolar mixture of diacid 1 and 4,4′‐oxydibenzoic acid with p‐ABH or m‐ABH exhibited a significantly increased fluorescence quantum efficiency in comparison with the homopolymers. Cyclic voltammetry results indicated that all the hydrazide and oxadiazole polymers exhibited an ambipolar (n‐ and p‐doping processes) and electrochromic behavior. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011.     

Synthesis of highly refractive polyimides derived from 3,6‐bis(4‐aminophenylenesulfanyl)pyridazine and 4,6‐bis(4‐aminophenylenesulfanyl)pyrimidine

A series of aromatic polyimides (PIs) containing pyridazine or pyrimidine in their main chains has been developed. All of the PIs were prepared from newly synthesized diamines, 3,6‐bis(4‐aminophenylenesulfanyl)pyridazine (APP), 4,6‐bis(4‐aminophenylenesulfanyl)pyrimidine (APPM) and aromatic dianhydrides, 4,4′‐[p‐thiobis(phenylenesulfanyl)]diphthalic anhydride (3SDEA) and 4,4′‐oxydiphthalic anhydride (ODPA) via the conventional two‐step polycondensation. The PIs showed good thermal stability with 10% weight loss at temperatures above 450 °C and glass transition temperatures above 190 °C. Films with a 10‐μm thickness exhibited good optical transparency above 80% at 500 nm, high refractive indices ranging from 1.7218 to 1.7499, and low birefringence between 0.0066 and 0.0102. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4886–4984, 2009     

Synthesis and properties of alternating copolyamide‐imides based on 2,6‐bis(4‐aminophenoxy)naphthalene and comparison with its related isomeric polymers

A series of novel polyamide‐imides III containing 2,6‐bis(phenoxy)naphthalene units were synthesized by 2,6‐bis(4‐aminophenoxy)naphthalene and various bis(trimellitimide)s in N‐methyl‐2‐pyrrolidone (NMP) using triphenyl phosphite and pyridine as condensing agents through direct polycondensation. The polymers were obtained in quantitative yield with inherent viscosities up to 1.53 dL/g. Most of the polymers showed good solubility in NMP, N,N‐dimethylacetamide, N,N‐dimethylformamide, and dimethyl sulfoxide and could be solution‐cast into transparent, flexible, and tough films. The films had tensile strengths of 84–111 MPa, elongations at break of 8–33%, and initial moduli of 2.2–2.8 GPa. Wide‐angle X‐ray diffraction revealed that most polymers III were amorphous. The glass‐transition temperatures of some of the polymers could be determined by differential scanning calorimetry traces, recorded at 247–290 °C. The polyamide‐imides exhibited excellent thermal stabilities and had 10% weight loss at temperatures in the range of 501–575 °C under nitrogen atmosphere. They left more than 57% residue even at 800 °C in nitrogen. A comparative study of some corresponding polyamide‐imides is also presented. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2591–2601, 2001     

Synthesis and characterization of poly(arylene ether)s containing 6‐(4‐hydroxyphenyl)pyridazin‐3(2H)‐one or 6‐(4‐hydroxyphenyl)pyridazine moieties

A series of novel soluble pyridazinone‐ or pyridazine‐containing poly(arylene ether)s were prepared by a polycondensation reaction. The pyridazinone monomer, 6‐(4‐hydroxyphenyl)pyridazin‐3(2H)‐one ( 1 ), was synthesized from the corresponding acetophenone and glyoxylic acid in a simple one‐pot reaction. The pyridazinone monomer was successfully copolymerized with bisphenol A (BPA) or 1,2‐dihydro‐4‐(4‐hydroxyphenyl)phthalazin‐1(2H)‐one (DHPZ) and bis(4‐fluorophenyl)sulfone to form high‐molecular‐weight polymers. The copolymers had inherent viscosities of 0.5–0.9 dL/g. The glass‐transition temperatures (T_g's) of the copolymers synthesized with BPA increased with increasing content of the pyridazinone monomer. The T_g's of the copolymers synthesized from DHPZ with different pyridazinone contents were similar to those of the two homopolymers. The homopolymers showed T_g's from 202 to 291 °C by differential scanning calorimetry. The 5% weight loss temperatures in nitrogen measured by thermogravimetric analysis were in the range of 411–500 °C. 4‐(6‐Chloropyridazin‐3‐yl)phenol ( 2 ) was synthesized from 1 via a simple one‐pot reaction. 2 was copolymerized with 4,4′‐isopropylidenediphenol and bis(4‐fluorophenyl)sulfone to form high‐T_g polymers. The copolymers with less than 80 mol % pyridazinone or chloropyridazine monomers were soluble in chlorinated solvents such as chloroform. The copolymers with higher pyridazinone contents and homopolymers were not soluble in chlorinated solvents but were still soluble in dipolar aprotic solvents such as N‐methylpyrrolidinone. The soluble polymers could be cast into flexible films from solution. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3328–3335, 2006     

Synthesis,characterization, and properties of new sequenced poly(ether amide)s based on 2‐(4‐aminophenyl)‐5‐aminobenzimidazole and 2‐(3‐aminophenyl)‐5‐aminobenzimidazole

A set of new aromatic poly(ether amide)s containing benzimidazole groups and ethylene oxide sequences of different lengths were synthesized and characterized. The new polymers were prepared from two benzimidazole diamines, 2‐(4‐aminophenyl)‐5‐aminobenzimidazole and 2‐(3‐aminophenyl)‐5‐aminobenzimidazole, and various oligo(ethylene oxide)dibenzoyl chlorides. They exhibited good solubility in polar aprotic solvents and glass‐transition temperatures in the range of 125–300 °C (the longer the ethylene oxide spacer was, the lower the glass‐transition temperature was). The new polyamides were essentially amorphous, as observed by X‐ray diffraction measurements and confirmed by differential scanning calorimetry measurements, by means of which no melting endotherm was observed in any case. The decomposition temperatures, as revealed by thermogravimetric analysis in nitrogen, were about 400 °C for all of them, regardless of the length of the ethylene oxide content or the phenylene ring orientation (meta or para) of the diamine moiety. The number of ethylene oxide linkages per repeat unit also determined the water uptake. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1414–1423, 2006     

Thermotropic liquid‐crystalline polyesters of 4,4′‐biphenol and phenyl‐substituted 4,4′‐biphenols with 4,4′‐oxybisbenzoic acid

A series of thermotropic polyesters, derived from 4,4′‐biphenol (BP), 3‐phenyl‐4,4′‐biphenol (MPBP), and 3,3′‐bis(phenyl)‐4,4′‐biphenol (DPBP), 4,4′‐oxybisbenzoic acid (4,4′‐OBBA), and other aromatic dicarboxylic acids as comonomers, were prepared by melt polycondensation and were characterized for their thermotropic liquid‐crystalline (LC) properties with a variety of experimental techniques. The homopolymer of BP with 4,4′‐OBBA and its copolymers with either 50 mol % terephthalic acid or 2,6‐naphthalenedicarboxylic acid had relatively high values of the crystal‐to‐nematic transition (448–460 °C), above which each of them formed a nematic LC phase. In contrast, the homopolymers of MPBP and DPBP had low fusion temperatures and low isotropization temperatures and formed nematic melts above the fusion temperatures. Each of these two polymers also exhibited two glass‐transition temperatures, which were associated with vitrified noncrystalline (amorphous) regions and vitrified LC domains, as obtained directly from melt polycondensation. As expected, they had higher glass‐transition temperatures (176–211 °C) than other LC polyesters and had excellent thermal stability (516–567 °C). The fluorescence properties of the homopolymer of DPBP with 4,4′‐OBBA, which was soluble in common organic solvents such as chloroform and tetrahydrofuran, were also included in this study. For example, it had an absorption spectrum (λ_max = 259 and 292 nm), an excitation spectrum (λ_ex = 258 and 292 nm with monitoring at 350 nm), and an emission spectrum (λ_em = 378 nm with excitation at 330 nm) in chloroform. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 141–155, 2002     

Synthesis and characterization of polyimides derived from (3‐amino‐2,4,6‐trimethylphenyl)‐(3′‐aminophenyl)methanone and aromatic dianhydrides

A series of new polyimides were prepared via the polycondensation of (3‐amino‐2,4,6‐trimethylphenyl)‐(3′‐aminophenyl)methanone and aromatic dianhydrides, that is, 3,3′,4,4′‐biphenyltetracarboxylic dianhydride (BPDA), 4,4′‐oxydiphthalic anhydride, 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride, and 2,2′‐bis(3,4‐dicarboxyphenyl) hexafluoropropane dianhydride. The structures of the polyimides were characterized by Fourier transform infrared and NMR measurements. The properties were evaluated by solubility tests, ultraviolet–visible analysis, differential scanning calorimetry, and thermogravimetric analysis. The two different meta‐position‐located amino groups with respect to the carbonyl bridge in the diamine monomer provided it with an unsymmetrical structure. This led to a restriction on the close packing of the resulting polymer chains and reduced interchain interactions, which contributed to the solubility increase. All the polyimides except that derived from BPDA had good solubility in strong aprotic solvents, such as N‐methyl‐2‐pyrrolidinone, N,N′‐dimethylacetamide, N,N‐dimethylformamide, and dimethyl sulfone, and in common organic solvents, such as cyclohexanone and chloroform. In addition, these polyimides exhibited high glass‐transition values and excellent thermal properties, with an initial thermal decomposition temperature above 470 °C and glass‐transition temperatures in the range of 280–320 °C. The polyimide films also exhibited good transparency in the visible‐light region, with transmittance higher than 80% at 450 nm and a cutoff wavelength lower than 370 nm. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1291–1298, 2006