Thermal and thermo‐oxidative degradation properties of poly(benzimidazole amide imide) copolymers

In this study, 3,3′‐dinitrobenzidine was first reacted with excess isophthaloyl chloride to form a monomer with dicarboxylic acid end groups. Two types of aromatic dianhydride, [viz., pyromellitic dianhydride (PMDA) and 3,3′,4,4′‐sulfonyldiphthalic anhydride (DSDA)] also were reacted with excess 4,4′‐diphenyl‐ methane diisocyanate (MDI) to form polyimide prepolymers terminated with isocyanate groups. The prepolymers were reacted further with the diacid monomer to form a nitro group–containing aromatic poly(amide imide) copolymers. The nitro groups in these copolymers were hydrogenated to form amine groups and cyclized at 180°C to form the poly(benzimidazole amide imide) copolymers in polyphosphoric acid (PPA), which acts as a cyclization agent. From the viscosity measurements, copolymer appeared to be a reasonably high molecular weight. From the differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) measurements it was shown that the glass transition temperature of copolymers was in the range of ～270–322°C. The 10% weight loss temperatures were in the range of 460 ～ 541°C in nitrogen and ～441–529°C in air, respectively. The activated energy and the integration parameter of degradation temperature of the copolymers were evaluated with the Doyle‐Ozawa method. It indicated that these copolymers have good thermal and thermo‐oxidative stability with the increase in imide content. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2072–2081, 2004     

Reduction and cyclization to form poly(benzimidazole amide imide) copolymers

Poly(amide imide) copolymers were synthesized with different molar ratios of 4,4‐diphenylmethane diisocyanate, two types of aromatic dianhydrides (pyromellitic dianhydride (PMDA) and 3,3′,4,4′‐sulfonyl diphthalic anhydride (DSDA)), and a diacid, which was derived from 3,3′‐dinitrobenzidine and isophthaloyl chloride in a previous work. In this study, the copolymers were further reacted with a reducing agent, and the nitro groups in the copolymers were hydrogenated into amine groups. Then, the amine‐group‐containing poly(amide imide) copolymers were cyclized at 180°C to form the poly(benzimidazole imide amide) copolymers in poly(phosphoric acid), which acted as a cyclizing agent. The resultant copolymers were soluble in sulfuric acid and poly(phosphoric acid) at room temperature and in sulfolane or N‐methyl‐2‐pyrrolidone under heating to 100°C with 5% lithium chloride. According to wide‐angle X‐ray diffraction, all the copolymers were amorphous. According to thermal analysis, the glass‐transition temperature ranged from 270 to 322°C, and the 10% weight‐loss temperature ranged from 460 to 541°C in nitrogen and from 441 to 529°C in air. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 378–386, 2004     

Preparation of soluble poly(amide imide) derivatives with metal salts and phosphorous compounds

Soluble poly(amide imide) derivatives were prepared through the direct polycondensation of 1,2,4‐benzenetricarboxylic acid and three diamines—bis[4‐(3‐aminophenoxy)phenyl]sulfone, bis(4‐aminophenyl)‐1,4‐diisopropylbenzene, and 4,4′‐oxydianilne—in the presence of metal salts and phosphorous compounds. Phosphonium salt, which was used as the initiating species and was prepared by the reaction of the metal salts and phosphorous compounds, reacted with 1,2,4‐benzenetricarboxylic acid to form acyloxy phosphonium salt, and then the salt was reacted with a diamine for the preparation of the prepolymers. The prepolymers were converted into the corresponding poly(amide imide)s in a homogeneous solution state at 180°C. The poly(amide imide)s showed good thermal and mechanical properties. Glass‐transition temperatures were observed from 240 to 270°C in differential scanning calorimetry traces. A melting endotherm was not observed for the polymers with differential scanning calorimetry. The initial decomposition occurred around 400°C according to thermogravimetric analysis, and major weight loss was observed from 610 to 680°C. The poly(amide imide)s had comparatively good solubility in aprotic polar solvents at concentrations high enough (～30%) for the fabrication of various forms. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1399–1407, 2002     

Synthesis and Their Thermal and Thermo-Oxidative Properties of Poly(benzimidazole amide imide) Copolymers

In this study, the 3′-dinitrobenzidine was first reacted with excess isophthaloyl chloride form a monomer with dicarboxylic acid end group. Two types of aromatic dianhydride (viz. pyromellitic dianhydride (PMDA) and 3,3′,4,4′-sulfonyldiphthalic anhydride (DSDA)), were also reacted with excess 4,4′-diphenyl-methane diisocyanate to form polyimide prepolymers terminated with an isocyanate group. The prepolymers was further extended with the diacid monomer to form a nitro group containing aromatic poly(amide-imide) copolymers. The nitro groups in these copolymers were hydrogenated to form amine groups and cyclized at 180 ^○C, to form the poly(benzimidazole amide imide) copolymers in polyphosphoric acid which acted as a cyclization agent. The resulting copolymers can be soluble in sulfuric acid and polyphosphoric acid, in sulfolane under heating to 100 ^○C, and in polar solvent N-methyl-2-pyrrolidone under heating to 100 ^○C with 5% lithium chloride. From the DSC and TGA measurements, it demonstrated that the glass transition temperature of copolymers exhibits a range of 270∼322 ^○C. The 10% weight loss temperatures exhibits a range of 460∼541 ^○C in nitrogen, and 441∼529 ^○C in air, respectively. The activation energy and the integration parameter of degradation temperature of the copolymers were evaluated by the Doyle–Ozawa method. It indicated that these copolymers exhibited good thermal and thermo-oxidative stability with the increase of imide content.     

Synthesis of aromatic poly(urea‐imide) with heterocyclic side‐chain structure

The poly(urea‐imide) copolymers with inherent viscosity of 0.81–1.08 dL/g were synthesized by reacting aryl ether diamine or its polyurea prepolymer with various diisocyanate‐terminated polyimide prepolymers. The aryl ether diamine was obtained by first nucleophilic substitution of phenolphthalein with p‐chloronitrobenzene in the presence of anhydrous potassium carbonate to form a dinitro aryl ether, and then further hydrogenated to diamine. The polyimide prepolymers were prepared by using 4,4′‐diphenylmethane diisocyanate to react with pyromellitic dianhydride, 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride, or 3,3′,4,4′‐sulfonyldiphthalic anhydride by using the direct one‐pot method to improve their solubility, but without sacrificing thermal property. These copolymers are amorphous and readily soluble in a wide range of organic solvents such as N‐methyl‐2‐pyrrolidone, dimethylimidazole, N,N‐dimethylacetamide, dimethyl sulfoxide, N,N‐dimethylformamide, m‐cresol, and sulfolane. All the poly(urea‐imides) have glass transition temperatures in the range of 205–240°C and show a 10 wt % loss at 326–352°C in nitrogen and 324–350°C in air. The tensile strength, elongation at break, and initial modulus of these copolymer films range from 42 to 79 MPa, 5 to 16%, and 1.23 to 2.02 GPa, respectively. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1719–1730, 1999     

Synthesis of thermostable polyamideimides and their properties

Thermostable polyamideimides with inherent viscosity of 1.02–1.50 dL/g were synthesized from reacting of diamine-terminated aromatic amide prepolymer with various diisocyanate terminated imide prepolymers. The imide prepolymer was prepared by using 4,4′-diphen-ylmethane diisocyanate to react with 3,3′,4,4′ benzophenonetetracarboxylic dianhydride, 3,3′,4,4′ sulfonyl diphthalic anhydride, or 4,4′-oxydiphthalic anhydride using the direct one-pot method to improve their solubility. Almost all of the polyamideimides were generally soluble in a wide range of organic solvents such as N,N-dimethylformamide, N,N-dimeth-ylacetamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, and pyridine at room temperature. Polymers with high imide content required high temperatures to dissolve. All polyamide-imides had a glass transition temperature of 223–352°C and showed a 10% weight loss temperature of 415–575°C in air and 424–583°C in nitrogen atmosphere. The tensile strength, elongation at break, and initial modulus of polymer films ranged from 61 to 108 MPa, 5 to 10% and 1.54 to 2.50 GPa, respectively. These copolymers were partly crystalline in structure as shown by X-ray pattern. © 1996 John Wiley & Sons, Inc.     

Synthesis of aromatic poly(amide-imide) copolymers containing para–meta benzoic structure

Thermostable poly(amide-imide)s containing para–meta benzoic structure were synthesized by reacting a para–meta benzoic polyamide prepolymer with various diisocyanate-terminated polyimide prepolymers. The polyamide prepolymers were prepared by first reacting m-phenylene diamine and isophthaloyl dichloride to form a poly(m-phenylphthalamide) prepolymer, then the terephthaloyl dichloride was subsequently added to form a para–meta benzoic polyamide prepolymer. The polyimide prepolymers were also prepared by using 4,4′-diphenylmethane disocyanate to react with pyromellitic dianhydride, 3,3′,4,4′-benzophenonetetracarboxylic dianhydride, or 3,3′,4,4′-sulfonyldiphthalic anhydride using the direct one-pot method to improve their solubility, but without sacrificing thermal and physical properties. From the experimental results, the inherent viscosity of the copolymers was 0.72–1.15 dL/g and they were readily soluble in a wide range of organic hot solvents such as N-methyl-2-pyrrolidone, dimethylimidazole, N,N-dimethylacetamide, dimethyl sulfoxide, and N,N-dimethylformamide; however, some of the copolymers were not soluble in pyridine. The solubility was related to their chemical structure. Those copolymers with sulfonyl and high amide content displayed good solubility. All the poly(amide-imide)s had a glass transition temperature of 260–324°C, but the melting point did not vary much. The 10% weight loss temperatures were in a range of 463–580°C in nitrogen and 450–555°C in an air atmosphere. The tensile strength, elongation at break, and initial modulus of the copolymer films ranged from 59 to 102 MPa, 3.1 to 5.1%, and 1.52 to 3.59 GPa, respectively. These copolymers, except those of high imide content (e.g., P-6, B-4, B-6 and D-6), which showed an amorphous structure, mostly display a crystalline morphology. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2671–2679, 1999     

Synthesis of thermostable nomex copoly(amide–imide) and their properties

Thermostable Nomex copoly(amide–imide)s with inherent viscosity of 0.72–1.31 dL/g were synthesized by reacting diacid-terminated Nomex prepolymer with various diisocyanate-terminated polyimide prepolymers. The polyimide prepolymer was prepared by using 4,4′-diphenylmethane diisocyanate to react with 3,3′,4,4′-benzophenonetetracarboxylic dianhydride, pyromellitic dianhydride, or 3,3′,4,4′-sulfonyl diphthalic anhydride using a direct one pot method in order to improve their solubility. The copolymers, except B-1, P-1, P-2, D-1, and D-2, could be dissolved in N, N-dimethylacetamide +5% lithium chloride at room temperature or dimethyl sulfoxide at high temperature but were not soluble in N,N-dimethylformamide or pyridine. The solubility is considered to be related to their crystallinity. Those copolymers with crystalline structure displayed poor solubility. All the Nomex copoly(amide–imide)s had glass transition temperatures in the range of 223–352°C and showed a 10% weight loss temperature of 438–574°C in air and 441–585°C in nitrogen atmosphere. The tensile strength, elongation at break, and initial modulus of polymer films ranged 63–118 MPa, 4–9% and 1.67–2.53 GPa, respectively. From the X-ray diffraction studies, copolymers of B-1, P-1, P-2, D-1, and D-2 with high content of PmIA showed a crystalline structure, but the others only displayed an amorphous morphology. © 1996 John Wiley amp; Sons, Inc.     

Thermally stable and organosoluble cardo binaphthylene based poly(amide imide)s and poly(ester imide)s

A new imide‐containing dicarboxylic acid based on a twisted binaphthylene unit, 2,2′‐bis(N‐trimellitoyl)‐1,1′‐binaphthyl (1), was synthesized from 1,1′‐binaphthyl‐2,2′‐diamine and trimellitic anhydride in glacial acetic acid. The structure of compound 1 was fully characterized with spectroscopic methods and elemental analysis. Series of thermally stable and organosoluble poly(amide imide)s (4a–4d) and poly(ester imide)s (5a–5d) with similar backbones were prepared by the triphenyl phosphite and diphenylchlorophosphate activated direct polycondensation of diimide dicarboxylic acid 1 with various aromatic diamines and diols, respectively. With due attention to the structural similarity of the resulting poly(amide imide)s and poly(ester imide)s, most of the differences between these two block copolyimides could be easily attributed to the presence of alternate amide or ester linkages accompanied by imide groups in the polymer backbone. The ultraviolet maximum wavelength values of the yellowish polymers were determined from their ultraviolet spectra. The crystallinity of these copolyimides was estimated by means of wide‐angle X‐ray diffraction, and the resultant polymers exhibited a nearly amorphous nature, except for the polymers derived from benzidine and 4,4′‐binaphthol. The poly(amide imide)s exhibited excellent solubility in a variety of highly polar aprotic solvents, whereas the poly(ester imide)s showed good solubility in less polar solvents. According to differential scanning calorimetry analyses, polymers 4a–4d and 5a–5d had glass‐transition temperatures between 331 and 357°C and between 318 and 342°C, respectively. The thermal behaviors of the obtained polymers were characterized by thermogravimetric analysis, and the 10% weight loss temperatures of the poly(amide imide)s and poly(ester imide)s were between 579 and 604°C and between 566 and 577°C in nitrogen, respectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3203–3211, 2006     

Synthesis and characterization of highly soluble poly(ether imide)s containing indane moieties in the main chain

A new indane containing unsymmetrical diamine monomer ( 3 ) was synthesized. This diamine monomer leads to a number of novel semifluorinated poly (ether imide)s when reacted with different commercially available dianhydrides like benzene‐1,2,4,5‐tetracarboxylic dianhydride (PMDA), benzophenone‐3,3′, 4,4′‐tetracarboxylic dianhydride (BTDA), 4,4′‐(hexafluoro‐isopropylidene)diphthalic anhydride (6FDA), 4,4′‐oxydiphthalic anhydride (ODPA), and 4,4′‐(4,4′‐Isopropylidenediphenoxy)bis(phthalic anhydride) (BPADA) by thermal imidization route. All the poly(ether imide)s showed excellent solubility in several organic solvents such as N‐methylpyrrolidone (NMP), N,N‐dimethylformamide (DMF), N,N‐dimethylacetamide (DMAc), tetrahydrofuran (THF), chloroform (CHCl₃) and dichloromethane (DCM) at room temperature. These light yellow poly (ether imide)s showed very low water absorption (0.19–0.30%) and very good optical transparency. Wide angle X‐ray diffraction measurements revealed that these polymers were amorphous in nature. The polymers exhibited high thermal stability up to 526°C in nitrogen with 5% weight loss, and high glass transition temperature up to 265°C. The polymers exhibited high tensile strength up to 85 MPa, modulus up to 2.5 GPa and elongation at break up to 38%, depending on the exact polymer structure. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and properties of thermostable naphthalate-containing copoly(amide–imide)s

Thermostable naphthalate-containing copoly(amide-imide)s with inherent viscosity of 0.53–0.96 dL/g were synthesized by reacting diacid-terminated naphthalate monomers with various diisocyanate-terminated polyimide prepolymers. The poly-imide prepolymers were prepared by using 4,4′-diphenylmethane diisocyanate to react with 3,3′,4,4′-benzophenonetetracarboxylic dianhydride, pyromellitic dianhydride, or 3,3′,4,4′-sulfonyl diphthalic anhydride using a direct one-pot method to improve their solubility without sacrificing their thermal properties. The copolymers, except the B-2 and P-2 series, can be dissolved in N,N-dimethylacetamide and 5% lithium chloride or dimethyl sulfoxide at high temperature but are not soluble in pyridine. The solubility of the copolymers is related to their chemical and crystalline structures. Those copolymers with sulfonyl or amorphous structures display good solubility. All the naphthalate-containing copoly(amide-imide)s have glass transition temperatures and melting points in the range of 223–312°C and 348–366°C, respectively, and show a 10% weight-loss temperature of 485–549°C in air and 465–564°C in a nitrogen atmosphere. The tensile strength, elongation at break, and initial modulus of polymer films range from 25–74 MPa, 4–9%, and 0.74–1.60 GPa, respectively. From the X-ray diffraction studies, copolymers of B-2, P-2, and D-2 with symmetrical 2,6-naphthalate amide structure are crystalline, but the others are amorphous. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:1581–1593, 1997     

Synthesis and characterization of novel poly(amide imide)s based on bis(p‐amidobenzoic acid)‐n‐trimellitylimido‐L‐leucine

N‐Trimellitylimido‐L ‐leucine was reacted with thionyl chloride, and N‐trimellitylimido‐L ‐leucine diacid chloride was obtained in a quantitative yield. The reaction of this diacid chloride with p‐aminobenzoic acid was performed in dry tetrahydrofuran, and bis(p‐amidobenzoic acid)‐N‐trimellitylimido‐L ‐leucine (5) was obtained as a novel optically active aromatic imide–amide diacid monomer in a high yield. The direct polycondensation reaction of the monomer imide–amide diacid 5 with 4,4′‐diaminodiphenylsulfone, 4,4′‐diaminodiphenylether, 1,4‐phenylenediamine, 1,3‐phenylenediamine, 2,4‐diaminotoluene, and benzidine (4,4′‐diaminobiphenyl) was carried out in a medium consisting of triphenyl phosphite, N‐methyl‐2‐pyrolidone, pyridine, and calcium chloride. The resulting novel poly(amide imide)s (PAIs), with inherent viscosities of 0.22–0.52 dL g^?1, were obtained in high yields, were optically active, and had moderate thermal stability. All of the compounds were fully characterized with IR spectroscopy, elemental analyses, and specific rotation. Some structural characterization and physical properties of these new optically active PAIs are reported. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 35–43, 2002; DOI 10.1002/app.10181     

Synthesis and characterization of novel optically active poly(amide‐imide)s

4,4′‐(Hexafluoroisopropylidene)‐bis‐(phthalic anhydride) (1) was reacted with L ‐leucine (2) in toluene solution at refluxing temperature in the presence of triethylamine and the resulting imide‐acid (4) was obtained in quantitative yield. The compound (4) was converted to the diacid chloride (5) by reaction with thionyl chloride. The polymerization reaction of the imide‐acid chloride (5) with 1,6‐hexamethylenediamine (6a) , benzidine (6b) , 4,4′‐diaminodiphenylmethane (6c) , 1,5‐diaminoanthraquinone (6d) , 4,4′‐sulfonyldianiline (6e) , 3,3′‐diaminobenzophenone (6f) , p‐phenylenediamine (6g) and 2,6‐diaminopyridine (6h) was carried out in chloroform/DMAc solution. The resulting poly(amide‐imide)s were obtained in high yield and are optically active and thermally stable. All of the above compounds were fully characterized by IR, elemental analyses and specific rotation. Some structural characterization and physical properties of those optically active poly(amide‐imide)s are reported. © 1999 Society of Chemical Industry     

Microwave‐assisted and conventional polycondensation reaction of optically active N,N′‐(4,4′‐sulphonediphthaloyl)‐bis‐L‐leucine diacid chloride with aromatic diamines

3,3′,4,4′‐Diphenylsulfonetetracarboxylic dianhydride ( 1 ) was reacted with L‐leucine ( 2 ) in acetic acid and the resulting imide‐acid ( 3 ) was obtained in high yield. The diacid chloride ( 4 ) was prepared from diacid derivative ( 3 ) by reaction with thionyl chloride. The polycondensation reaction of diacid chloride ( 4 ) with several aromatic diamines such as 4,4′‐sulfonyldianiline ( 5a ), 4,4′‐diaminodiphenyl methane ( 5b ), 4,4′‐diaminodiphenylether ( 5c ), p‐phenylenediamine ( 5d ), m‐phenylenediamine ( 5e ), 2,4‐diaminotoluene ( 5f ), and 1,5‐diaminonaphthalene ( 5g ) 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 were also performed under two conventional methods: low temperature solution polycondensation in the presence of trimethylsilyl chloride, and a short period reflux conditions. A series of optically active poly(amide‐imide)s with inherent viscosity of 0.25–0.42 dL/g were obtained with high yield. All of the above polymers were fully characterized by IR, elemental analyses, and specific rotation techniques. Some structural characterizations and physical properties of these optically active poly (amide‐imide) s are reported. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2992–3000, 2004     

Synthesis and properties of new poly(amide imide)s containing trimellitic rings and hydantoin moieties in the main chain under microwave irradiation

Trimellitic anhydride was reacted with 4,4′‐diaminodiphenyl ether in a mixture of acetic acid and pyridine (3 : 2) at room temperature and was refluxed at 90–100°C, and N,N′‐(4,4′‐diphenylether) bistrimellitimide (3) was obtained in a quantitative yield. 3 was converted into N,N′‐(4,4′‐diphenylether) bistrimellitimide diacid chloride (4) by a reaction with thionyl chloride. Then, six new poly(amide imide)s were synthesized under microwave irradiation with a domestic microwave oven through the polycondensation reactions of 4 with six different derivatives of 5,5‐disubstituted hydantoin in the presence of a small amount of a polar organic medium such as o‐cresol. The polycondensation proceeded rapidly and was completed within 7–10 min, producing a series of new poly(amide imide)s in high yields with inherent viscosities of 0.27–0.66 dL/g. The resulting poly(amide imide)s were characterized by elemental analysis, viscosity measurements, differential scanning calorimetry, thermogravimetric analysis, derivative thermogravimetry, solubility testing, and Fourier transform infrared spectroscopy. All the polymers were soluble at room temperature in polar solvents such as N,N‐dimethylacetamide, N,N‐dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, and N‐methyl‐2‐pyrrolidone. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3447–3453, 2004     

Addition polyimide adhesives containing various end groups

Addition polyimide oligomers have been synthesized from 3,3′,4,4′-benzophenone tetracarboxylic acid dianhydride and 3,3′-methylenedianiline using a variety of latent crosslinking groups as end-caps. The nominal 1300 molecular weight imide prepolymers were isolated and characterized for solubility in amide, chlorinated and ether solvents, melt-flow and cure properties, glass transition temperature, and thermal stability on heating in an air atmosphere. Adhesive strengths of the polyimides were obtained both at ambient and elevated temperatures before and after aging at 232°C. Properties of the novel addition polyimides were compared to a known nadic end-capped adhesive, LARC-13.     

Synthesis and properties of hydrogen‐bonded poly(amide‐imide) hybrid films

Poly(amide‐imide), PI, hybrid films are prepared by using sol–gel techniques. First, the poly(amide amic acid) with controlled block chain length of 5000 and 10,000 g/mol and uncontrolled chain length are synthesized by condensation reaction with 4,4′‐diaminodiphenyl ether (ODA), 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride (BTDA), trimellitic anhydride chloride (TMAC) and terminated with p‐aminopropyltrimethoxysilane (APrTMOS). And then the imidization reactions of poly (amide amic acid) are proceeded to obtain the poly (amide‐imide) hybrid film. Hybrid films with 5000 g/mol block chain length possess higher storage modulus, lower glass transition temperature and damping intensity comparing to films with 10,000 g/mol block chain length. The addition of TMAC to the poly(amide‐imide) hybrids is due to the increase of toughness and intermolecular hydrogen bonding, which is the average strength of intermolecular bonding and studied by the hydrogen‐bonded fraction (f_bonded), frequency difference (Δν) and shiftment. Meanwhile, PI hybrid films containing more APrTMOS and TMAC content possess higher thermal and mechanical properties. On the other hand, hybrid films with 10,000 g/mol block chain length and more TMAC content have higher gas permeabilities than other films. The degradation temperatures of 5 wt % loss of all hybrid films are all higher than 540°C and increased as the increase of TMAC content. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

New poly(amide imide imide)s based on tetraimide dicarboxylic acid condensed from 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride,m‐aminobenzoic acid,and 4,4″‐oxydianiline and various aromatic diamines

A series of new, organosoluble, and light‐colored poly(amide imide imide)s were synthesized from tetraimide dicarboxylic acid ( I ) and various aromatic diamines by direct polycondensation with triphenyl phosphite and pyridine as condensing agents. I was prepared by the azeotropic condensation of 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride, m‐aminobenzoic acid, and 4,4′‐oxydianiline at a 2/2/1 molar ratio in N‐methyl‐2‐pyrrolidone (NMP)/toluene. The thin films cast from N,N‐dimethylacetamide (DMAc) had cutoff wavelengths shorter than 400 nm (365–394 nm) and color coordinate b* values between 13.10 and 36.07; these polymers were lighter in color than the analogous poly(amide imide)s and isomeric polymers. All of the polymers were readily soluble in a variety of organic solvents, including NMP, DMAc, N,N‐dimethylformamide, dimethyl sulfoxide, and even less polar dioxane and tetrahydrofuran. The cast films exhibited tensile strengths of 90–104 MPa, elongations at break of 7–22%, and initial moduli of 1.9–2.4 GPa. The glass‐transition temperatures of the polymers were recorded at 274–319°C. They had 10% weight losses at temperatures beyond 520°C and left more than a 50% residue even at 800°C in nitrogen. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 669–679, 2003     

Novel trifluoromethyl‐containing poly(amide–imide)s: Organosolubility,optical behavior,thermostability, and crystallinity

A new dicarboxylic acid monomer, 2,6‐bis(1,3‐dioxo‐5‐carboxyisoindolin‐2‐yl)‐4,4′‐bis(trifluoromethyl)‐1,1′‐diphenyl ether (IFDPE), bearing two preformed imide rings was synthesized via a three‐step manner from 4‐(trifluoromethyl)phenol and 4‐chloro‐3,5‐dinitrobenzotrifluoride. The monomer IFDPE was then used to prepare a series of novel trifluoromethyl‐containing poly(amide–imide)s via a direct phosphorylation polycondensation with various aromatic diamines. The intrinsic viscosities of the polymers were found to be in the range 0.86–1.02 d/g. The weight‐ and number‐average molecular weights of the resulting polymers were determined with gel permeation chromatography. The polymeric samples were readily soluble in a variety of organic solvents and formed low‐color, flexible thin films via solution casting. The values of the absorption edge wavelength were determined by ultraviolet–visible spectroscopy, and all of the resulting poly (amide–imide)s films exhibited high optical transparency. The resulting polymers showed moderately high glass‐transition temperatures in the range 295–324°C and had 10% weight loss temperatures in excess of 524°C in nitrogen. The crystallinity extents were qualitatively investigated with wide‐angle X‐ray diffraction measurements. Scanning electron microscopy images revealed an agglomerated bulk with nonuniformity on the surface. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Dynamic mechanical properties of quinazolone–imide block copolymer

Dynamic mechanical properties have been investigated over the temperature range of?150–360°C for the quinazolone–imide copolymers, prepared by condensation of the amine-terminated quinazolone prepolymer with a stoichiometric quantity of pyromellitic dianhydride or 3,3′,4,4′-benzophenone-tetracarboxilic dianhydride. Both copolymers have, respectively, the low-temperature β-relaxation and the β^*-relaxation, as well as the case of poly(4,4′-oxydiphenylene–pyromellite-imide) (Kapton) examined for comparison. These relaxations seem to contribute to toughness of the copolymers. The α-relaxations for both copolymers occurred at much the same temperature of 320°C, which can be assigned to a large scale segmental motion of the quinazolone chain sequence. The α-peak temperatures shifted into higher temperatures by heat aging. This can be explained in terms of crosslinking in the copolymers, supported by swelling test in hot m-cresol and IR spectroscopy.