Preparation and properties of new poly(amide‐imide)s based on 1,4‐bis(4‐trimellitimidophenoxy)naphthalene and aromatic diamines

A diimide dicarboxylic acid, 1,4‐bis(4‐trimellitimidophenoxy)naphthalene (1,4‐BTMPN), was prepared by condensation of 1,4‐bis(4‐aminophenoxy)naphthalene and trimellitic anhydride at a 1 : 2 molar ratio. A series of novel poly(amide‐imide)s (IIa–k) with inherent viscosities of 0.72 to 1.59 dL/g were prepared by triphenyl phosphite‐activated polycondensation from the diimide‐diacid 1,4‐BTMPN with various aromatic diamines (Ia–k) in a medium consisting of N‐methyl‐2‐pyrrolidinone (NMP), pyridine, and calcium chloride. The poly(amide‐imide)s showed good solubility in NMP, N,N‐dimethylacetamide, and N,N‐dimethylformamide. The thermal properties of the obtained poly(amide‐imide)s were examined with differential scanning calorimetry and thermogravimetry analysis. The synthesized poly(amide‐imide)s possessed glass‐transition temperatures in the range of 215 to 263°C. The poly(amide‐imide)s exhibited excellent thermal stabilities and had 10% weight losses at temperatures in the range of 538 to 569°C under a nitrogen atmosphere. A comparative study of some corresponding poly(amide‐imide)s also is presented. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1–8, 2000     

New poly(amide–imide)s syntheses. XXIII. Synthesis and properties of poly(amide–imide)s derived from 4,4′‐[1,4‐phenylenebis(isopropylidene‐1,4‐phenyleneoxy)]dianiline and various bis(trimellitimide)s

A series of poly(amide–imide)s III_a–m containing flexible isopropylidene and ether groups in the backbone were synthesized by the direct polycondensation of 4,4′‐[1,4‐phenylenebis(isopropylidene‐1,4‐phenyleneoxy)]dianiline (PIDA) with various bis(trimellitimide)s II_a–m in N‐methyl‐2‐pyrrolidone (NMP) using triphenyl phosphite and pyridine as condensing agents. The resulting poly(amide–imide)s had inherent viscosities in the range of 0.80–1.36 dL/g. Except for those from the bis(trimellitimide)s of p‐phenylenediamine and benzidine, all the polymers could be cast from DMAc into transparent and tough films. They exhibited excellent solubility in polar solvents. The 10% weight loss temperatures of the polymers in air and in nitrogen were all above 495°C, and their T_g values were in the range of 201–252°C. Some properties of poly(amide–imide)s III were compared with those of the corresponding poly(amide–imide)s V prepared from the bis(trimellitimide) of diamine PIDA and various aromatic diamines. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 69–76, 1999     

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     

New rigid-rod poly(benzoxazole-imide)s containing chloro-substituted p-phenylene units in the main chain

A series of new poly(o-hydroxy amide-imide)s with high molecular weights were synthesized by low-temperature solution polycondensation from a preformed imide ring and chloro- or dichloro-substituted p-phenylene-containing diacid chlorides of 2,5-bis(trimellitimido)chlorobenzene or 1,4-bis(trimellitimido)-2,5-dichlorobenzene and three bis(o-amino phenol)s. All the poly(o-hydroxy amide-imide)s were readily soluble in a variety of organic solvents such as N-methyl-2-pyrrolidone and N,N-dimethylacetamide. Transparent and flexible films of these polymers were cast from their solutions. The cast films had tensile strengths ranging from 88 to 102 MPa and elongations at break of 8–12%. Subsequent thermal cyclodehydration of the poly(o-hydroxy amide-imide)s afforded novel poly(benzoxazole-imide)s. The poly(benzoxazole-imide)s exhibited glass-transition temperatures in the range of 310–338 °C and were stable up to 500 °C in nitrogen, with 10% weight-loss temperatures recorded between 550 and 570 °C in nitrogen. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 4151–4158, 1999     

Synthesis and properties of novel aromatic poly(o-hydroxy amide)s and polybenzoxazoles based on the bis(ether benzoyl chloride)s from hydroquinone and its methyl-, tert-butyl-, and phenyl-substituted derivatives

Four series of poly(o-hydroxy amide)s were prepared by the low-temperature solution polycondensation of the bis(ether benzoyl chloride)s extended from hydroquinone and its methyl-, tert-butyl-, or phenyl-substituted derivatives with three bis(o-aminophenol)s. Most of the poly(o-hydroxy amide)s displayed an amorphous nature, were readily soluble in various polar solvents such as N,N-dimethylacetamide (DMAc), and could be solution-cast into flexible and tough films. These poly(o-hydroxy amide)s had glass transition temperatures (T_g) in the range of 152–185°C and could be thermally cyclodehydrated into the corresponding polybenzoxazoles approximately in the region of 200–400°C, as evidenced by the DSC thermograms. The thermally converted benzoxazole polymers exhibited T_gs in the range of 215–247°C and did not show significant weight loss before 500°C either in nitrogen or in air. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2129–2136, 1999     

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     

Partially bio‐based poly(amide imide)s by polycondensation of aromatic diacylhydrazides based on lignin‐derived phenolic acids and aromatic dianhydrides: Synthesis,characterization, and computational studies

Two new bio‐based diacylhydrazide monomers, namely, 4,4′‐(propane‐1,3‐diylbis(oxy))bis(3‐methoxybenzohydrazide) and 4,4′‐(propane‐1,3‐diylbis(oxy))bis(3,5‐dimethoxybenzohydrazide) were synthesized starting from lignin‐derived phenolic acids, namely, vanillic acid and syringic acid. A series of poly(amide imide)s was synthesized by polycondensation of these diacylhydrazide monomers with commercially available aromatic dianhydrides. Poly(amide imide)s showed inherent viscosity in the range 0.44–0.56 dL g^?1 and exhibited good solubility in organic solvents. Poly(amide imide)s could be cast into transparent, flexible, and tough films from their N ,N‐dimethylacetamide solutions. Poly(amide imide)s showed 10% weight loss in the temperature range 340–364 °C indicating their good thermal stability. Glass transition temperature (T _g) of poly(amide imides)s were measured by DSC and DMA which were in the range 201–223 °C and 214–248 °C, respectively. The T _g values of poly(amide imide)s were dependent on the number methoxy substituents on aromatic rings of diacylhydrazide monomers. Molecular dynamics simulation studies revealed that chain rigidity is the dominant factor for observed trends in T _g. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 3636–3645     

Fluorinated polyamides and poly(amide imide)s based on 1,4‐bis(4‐amino‐2‐trifluromethylphenoxy)benzene,aromatic dicarboxylic acids,and various monotrimellitimides and bistrimellitimides: Syntheses and properties

A CF₃‐containing diamine, 1,4‐bis(4‐amino‐2‐trifluromethylphenoxy) benzene ( I ), was prepared from hydroquinone and 2‐chloro‐5‐nitrobenzotrifluoride. Imide‐containing diacids ( V _a–h and VI _a,b ) were prepared through the condensation reaction of amino acids, aromatic diamines, and trimellitic anhydride. Then, a series of soluble fluorinated polyamides ( VII _a–h ) and poly(amide imide)s ( VIII _a–h and X _a,b ) were synthesized from I with various aromatic diacids ( II _a–h ) and imide‐containing diacids ( V _a–h and VI _a,b ) via direct polycondensation with triphenyl phosphate and pyridine. The polyamides and poly(amide imide)s had inherent viscosities of 1.00–1.70 and 0.79–1.34 dL/g, respectively. All the synthesized polymers showed excellent solubility in amide‐type solvents such as N‐methyl‐2‐pyrrolidinone, N,N‐dimethylacetamide, and N‐dimethylformamide and afforded transparent and tough films via solvent casting. Polymer films of VII _a–h , VIII _a–h , and X _a,b had tensile strengths of 91–113 MPa, elongations to break of 8–40%, and initial moduli of 2.1–2.8 GPa. The glass‐transition temperatures of the polyamides and poly(amide imide)s were 254–276 and 255–292 °C, respectively, and the imide‐containing poly(amide imide)s had better thermal stability than the polyamides. The polyamides showed higher transparency and were much lighter in color than the poly(amide imide)s, and their cutoff wave numbers were below 400 nm. In comparison with isomeric IX _{c – h} , poly(amide imide)s VIII _c–h exhibited less coloring and showed lower yellowness indices. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3116–3129, 2004     

Synthesis and properties of organosoluble poly(amide‐imide)s with propeller‐shaped 1,1,1‐triphenylethane units in the main chain

A dicarboxylic acid {1,1‐bis[4‐(4‐trimellitimidophenoxy)phenyl]‐1‐phenylethane ( II )} bearing two performed imide rings was prepared from the condensation of 1,1‐bis[4‐(4‐aminophenoxy)phenyl]‐1‐phenylethane and trimellitic anhydride in a 1/2 molar ratio. A novel family of poly(amide‐imide)s with inherent viscosities of 0.83–1.51 dL/g was prepared by triphenyl phosphite‐activated polycondensation from the diimide‐diacid II with various aromatic diamines in a medium consisting of N‐methyl‐2‐pyrrolidinone (NMP), pyridine, and calcium chloride. Because the 1,1,1‐triphenylethane group of II was unsymmetrical, most of the resulting polymers showed an amorphous nature and were readily soluble in polar solvents such as NMP and N,N‐dimethylacetamide. All the soluble poly(amide‐imide)s afforded tough, transparent, and flexible films, which had tensile strengths ranging from 88 to 102 MPa, elongations at break from 6 to 11%, and initial moduli from 2.23 to 2.71 GPa. The synthesized poly(amide‐imide)s possessed glass‐transition temperatures from 250 to 287 °C. The poly(amide‐imide)s exhibited excellent thermal stabilities and had 10% weight losses from 501 to 534 °C under a nitrogen atmosphere. A comparative study of some corresponding poly(amide‐imide)s is also presented. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 775–787, 2001     

Soluble poly(amide–imide)s prepared by one‐pot solution condensation

A new one‐pot procedure for imide–acid monomer synthesis and polymerization is reported for four new poly(amide–imide)s. Bisphenol A dianhydride (BPADA) was reacted with twice the molar amount of 3‐aminobenzoic acid (3ABA) or 3‐amino‐4‐methylbenzoic acid (3A4MBA) in 1‐methyl‐2‐pyrrolidinone (NMP) and toluene mixture, and the amic acid intermediates cyclized in solution to give two diimide‐containing dicarboxylic acid monomers. Without isolation, the diacid monomers were then polymerized with either 1,3‐diaminomesitylene (DAM) or 1,5‐diaminonaphthalene (1,5NAPda) using triphenyl phosphite‐activation to give a series of four soluble poly(amide–imide)s, PAI. Isolation and purification of the dicarboxylic acid monomers was not necessary for formation of high molecular weight polymers as indicated by intrinsic viscosities of 0.64–1.04 dL/g determined in N,N‐dimethylacetamide (DMAc). All of the PAI were soluble in polar aprotic solvents such as NMP, DMAc, and dimethyl sulfoxide (DMSO). Glass transition temperatures ranged from 243 to 279°C by DSC, and 5% weight loss temperatures were above 400°C in both air and nitrogen. Flexible films cast from DMAc were light yellow, transparent, and tough. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1183–1188, 1999     

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 fluorinated poly(amide imide)s derived from 1,4‐bis(2′‐trifluoromethyl‐4′‐trimellitimidophenoxy)benzene and aromatic diamines

A series of fluorinated poly(amide imide)s were prepared from 1,4‐bis(2′‐trifluoromethyl‐4′‐trimellitimidophenoxy)benzene and various aromatic diamines [3,3′,5,5′‐tetramethyl‐4,4′‐diaminediphenylmethane, α,α‐bis(4‐amino‐3,5‐dimethyl phenyl)‐3′‐trifluoromethylphenylmethane, 1,4‐bis(4′‐amino‐2′‐trifluoromethylphenoxy)benzene, 4‐(3′‐trifluoromethylphenyl)‐2,6‐bis(3′‐aminophenyl)pyridine, and 1,1‐bis(4′‐aminophenyl)‐1‐(3′‐trifluoromethylphenyl)‐2,2,2‐trifluoroethane]. The fluorinated poly(amide imide)s, prepared by a one‐step polycondensation procedure, had good solubility both in strong aprotic solvents, such as N‐methyl‐2‐pyrrolidinone, dimethylacetamide, dimethylformamide, dimethyl sulfoxide, and cyclopentanone, and in common organic solvents, such as tetrahydrofuran and m‐cresol. Strong and flexible polymer films with tensile strengths of 84–99 MPa and ultimate elongation values of 6–9% were prepared by the casting of polymer solutions onto glass substrates, followed by thermal baking. The poly(amide imide) films exhibited high thermal stability, with glass‐transition temperatures of 257–266 °C and initial thermal decomposition temperatures of greater than 540 °C. The polymer films also had good dielectric properties, with dielectric constants of 3.26–3.52 and dissipation factors of 3.0–7.7 × 10^?3, and acceptable electrical insulating properties. The balance of excellent solubility and thermal stability associated with good mechanical and electrical properties made the poly(amide imide)s potential candidates for practical applications in the microelectronics industry and other related fields. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1831–1840, 2003     

Synthesis and properties of new adamantane‐based poly(ether imide)s

A new adamantane‐based bis(ether anhydride), 2,2‐bis[4‐(3,4‐dicarboxyphenoxy)phenyl]adamantane dianhydride, was prepared in three steps starting from nitrodisplacement of 4‐nitrophthalonitrile with the potassium phenolate of 2,2‐bis(4‐hydroxyphenyl)adamantane. A series of adamantane‐containing poly(ether imide)s were prepared from the adamantane‐based bis(ether anhydride) and aromatic diamines by a conventional two‐stage synthesis in which the poly(ether amic acid)s obtained in the first stage were heated stage‐by‐stage at 150–270°C to give the poly(ether imide)s. The intermediate poly(ether amic acid)s had inherent viscosities between 0.56 and 1.92 dL/g. Except for those from p‐phenylenediamine, m‐phenylenediamine, and benzidine, all the poly(ether amic acid) films could be thermally converted into transparent, flexible, and tough poly(ether imide) films. All the poly(ether imide)s showed limited solubility in organic solvents, although they were amorphous in nature as evidenced by X‐ray diffractograms. Glass transition temperatures of these poly(ether imide)s were recorded in the range of 242–317°C by differential scanning calorimetry and of 270–322°C by dynamic mechanical analysis. They exhibited high resistance to thermal degrdation, with 10% weight loss temperatures being recorded between 514–538°C in nitrogen and 511–527°C in air. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1619–1628, 1999     

Synthesis and characterization of poly(ether naphthalimide)s

A series of new poly(ether imide)s containing the naphthalimide moiety were prepared from bis(4-fluorobenzoyl)naphthalimides and several bisphenols by aromatic nucleophilic displacement polymerization. These polyimides had inherent viscosities in the range of 0.31–1.04 dL/g in chloroform and glass transition temperatures of 283.0–341.6°C by differential scanning calorimetry. The onset temperature for 5% weight loss for all the polymers was over 448°C, as assessed by thermogravimetry at a heating rate 10°C/min in nitrogen. In addition, these novel polyimides exhibited good solubility in organic solvents including N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, 1,1,2,2-tetrachloroethane and chloroform. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3227–3231, 1999     

Synthesis and characterization of new type soluble poly(amide–imide)s based on 6FDA imide modified polyterephthalamides

A series of new poly(amide–imide)s (PAIs, series III ) with good processability and characteristics was synthesized by utilizing organosoluble polyimide (PI, 6FDA–PI series) to improve poor‐solubility polyamide (PA, PTPA series), which used terephthalic acid (TPA) as a monomer. The III series PAIs were synthesized starting from the 2 : 1 molar ratio of aromatic diamines ( I ) and 6FDA to prepare imide ring‐preformed diamines ( II ) and then reacted with equimolar amount of TPA by direct polycondensation. Furthermore, by adjustment of the stoichiometry of the I , II, and TPA monomers, PAIs IV having various components were prepared. Most of the resulting PAIs having inherent viscosities between 0.70 and 1.74 dL/g were obtained in quantitative yields, and they were readily soluble in polar solvents such as N,N‐dimethylacetamide, N‐methyl‐2‐pyrrolidone, dimethylformamide, and dimethyl sulfoxide. All of the soluble PAIs afforded transparent, flexible, and tough films. The glass‐transition temperatures of PAIs III were in the range of 236–256 °C, and the 10% weight loss temperatures were recorded at 522–553 °C in nitrogen. The char yields of the III series polymers in nitrogen atmosphere were all higher than 56% even at 800 °C. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 93–104, 2001     

Synthesis and properties of organosoluble poly(amide imide imide)s based on tetraimide dicarboxylic acid condensed from 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride, 4,4′‐oxydianiline,and trimellitic anhydride and various aromatic diamines

A novel tetraimide dicarboxylic acid was synthesized with the ring‐opening addition of 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride, 4,4′‐oxydianiline, and trimellitic anhydride in a 1/2/2 molar ratio in N‐methyl‐2‐pyrrolidone followed by azeotropic condensation to tetraimide dicarboxylic acid. A series of poly(amide imide imide)s (PAIIs) with inherent viscosities of 0.8–1.1 dL/g were prepared from tetraimide dicarboxylic acid with various aromatic diamines by direct polycondensation. Most of the PAIIs were readily soluble in a variety of amide polar solvents and even in less polar m‐cresol and pyridine. Solvent‐cast films had tensile strengths ranging from 99 to 106 MPa, elongations at break ranging from 8 to 13%, and initial moduli ranging from 2.0 to 2.3 GPa. The glass‐transition temperatures of these PAIIs were recorded at 244–276 °C. They had 10% weight losses at temperatures above 520 °C in air or nitrogen atmospheres. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1092–1102, 2002     

Synthesis and properties of poly(ether imide)s derived from 2,6-bis(3,4-dicarboxyphenoxy)naphthalene dianhydride and aromatic diamines

A new naphthalene unit-containing bis(ether anhydride), 2,6-bis(3,4-dicarboxyphenoxy)naphthalene dianhydride, was synthesized in three steps starting from the nucleophilic nitrodisplacement reaction of 2,6-dihydroxynaphthalene and 4-nitrophthalonitrile in N,N-dimethylformamide (DMF) solution in the presence of potassium carbonate, followed by alkaline hydrolysis of the intermediate bis(ether dinitrile) and subsequent dehydration of the resulting bis(ether diacid). High-molar-mass aromatic poly(ether imide)s were prepared using a conventional two-step polymerization process from the bis(ether anhydride) and various aromatic diamines. The intermediate poly(ether amic acid)s had inherent viscosities of 0.65–2.03 dL/g. The films of poly(ether imide)s derived from two rigid diamines, i.e. p-phenylenediamine and benzidine, crystallized during the thermal imidization process. The other poly(ether imide)s belonged to amorphous materials and could be fabricated into transparent, flexible, and tough films. These aromatic poly(ether imide) films had yield strengths of 104–131 MPa, tensile strengths of 102–153 MPa, elongation to break of 8–87%, and initial moduli of 1.6–3.2 GPa. The glass transition temperatures (T_g's) of poly(ether imide)s were recorded in the range of 220–277°C depending on the nature of the diamine moiety. All polymers were stable up to 500°C, with 10% weight loss being recorded above 550°C in both air and nitrogen atmospheres. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1657–1665, 1998     

New poly(amide–imide) syntheses. XXI. Synthesis and properties of aromatic poly(amide–imide)s based on 2,6-bis(4-trimellitimidophenoxy)naphthalene and aromatic diamines

A novel polymer-forming diimide–diacid, 2,6-bis(4-trimellitimidophenoxy)naphthalene, was prepared by the condensation reaction of 2,6-bis(4-aminophenoxy)naphthalene with trimellitic anhydride (TMA). A series of novel aromatic poly(amide–imide)s containing 2,6-bis(phenoxy)naphthalene units were prepared by the direct polycondensation of the diimide–diacid with various aromatic diamines using triphenyl phosphite (TPP) in N-methyl-2-pyrrolidone (NMP)/pyridine solution containing dissolved calcium chloride. Thirteen of the obtained polymers had inherent viscosities above 1.01 dL/g and up to 2.30 dL/g. Most of polymers were soluble in polar solvents such as DMAc and could be cast from their DMAc solutions into transparent, flexible, and tough films. These films had tensile strengths of 79–117 MPa, elongation-at-break of 7–61%, and initial moduli of 2.2–3.0 GPa. The wide-angle X-ray diffraction revealed that some polymers are partially crystalline. The glass transition temperatures of some polymers could be determined with the help of differential scanning calorimetry (DSC) traces, which were recorded in the range 232–300°C. All the poly(amide–imide)s exhibited no appreciable decomposition below 450°C, and their 10% weight loss temperatures were recorded in the range 511–577°C in nitrogen and 497–601°C in air. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 919–927, 1998     

Novel method for preparation of poly(benzoxazinone‐imide)

A novel method was developed to prepare poly(benzoxazinone‐imide) by the dealcoholization of poly(amide‐imide), having pendent ethoxycarbonyl groups, which was prepared from poly(amide acid). The poly(amide acid) was prepared from the reaction of pyromellitic dianhydride and 4,4′‐diamino‐6‐ethoxycarbonyl benzanilide. The curing behavior of the poly(amide acid) was monitored by DSC, which indicated the presence of two broad endotherms, one with maximum at 153 °C due to imide‐ring formation and the other with maximum at 359 °C due to benzoxazinone‐ring formation. The poly(amide acid) was thermally treated at 300 °C/1 h to get poly(amide‐imide) with pendent ester groups, then at 350 °C/2 h to convert into poly(benzoxazinone‐imide) by dealcoholization. Viscoelastic measurements of the poly(amide‐imide) showed that the storage modulus dropped at about 280 °C with glass‐transition temperature (T_g ) at about 340 °C. The storage modulus of poly(benzoxazinone‐imide), however, was almost constant up to 400 °C and no T_g was detected below 400 °C. Also, the tensile modulus and tensile strength of the poly(benzoxazinone‐imide) was much higher than that of the poly(amide‐imide). The 5% decomposition of poly(benzoxazinone‐imide) film was at 535 °C, which reflects its excellent thermal stability. Also, poly(benzoxazinone‐imide) showed more hydrolytic stability against alkali in comparison to polyimides. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1647–1655, 2000     

Synthesis and characterization of soluble polyimides derived from 2′,5′‐bis(3,4‐dicarboxyphenoxy)‐p‐terphenyl dianhydride

A novel bis(ether anhydride) monomer, 2′,5′‐bis(3,4‐dicarboxyphenoxy)‐p‐terphenyl dianhydride, was synthesized from the nitro displacement of 4‐nitrophthalonitrile by the phenoxide ion of 2′,5′‐dihydroxy‐p‐terphenyl, followed by alkaline hydrolysis of the intermediate bis(ether dinitrile) and cyclodehydration of the resulting bis(ether diacid). A series of new poly(ether imide)s bearing laterally attached p‐terphenyl groups were prepared from the bis(ether anhydride) with various aromatic diamines via a conventional two‐stage process that included ring‐opening polyaddition to form the poly(amic acid)s followed by thermal or chemical imidization to the poly(ether imide)s. The inherent viscosities of the poly(amic acid) precursors were in the range of 0.62–1.26 dL/g. Most of the poly(ether imide)s obtained from both routes were soluble in polar organic solvents, such as N,N‐dimethylacetamide. All the poly(ether imide)s could afford transparent, flexible, and strong films with high tensile strengths. The glass‐transition temperatures of these poly(ether imide)s were recorded as between 214 and 276 °C by DSC. The softening temperatures of all the poly(ether imide) films stayed in the 207–265 °C range according to thermomechanical analysis. For all the polymers significant decomposition did not occur below 500 °C in nitrogen or air atmosphere. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1008–1017, 2004