Synthesis and characterization of new soluble polyamides from 1,1‐bis[4‐(4‐carboxyphenoxy)phenyl]‐4‐tert‐butylcyclohexane and various diamines

A new dicarboxylic acid monomer, 1,1‐bis[4‐(4‐carboxyphenoxy)phenyl]‐4‐tert‐butylcyclohexane, bearing a pendent tert‐butylcyclohexylidene group was prepared in three steps from 4‐tert‐butylcyclohexanone. The monomer was reacted with various diamines to produce a series of new polyamides with triphenyl phosphite and pyridine as condensing agents. These polyamides were produced with inherent viscosities of 0.74 to 1.02 dL g⁻¹. All the polymers were characterized by X‐ray diffraction that revealed this amorphous nature. These polymers exhibited excellent solubility in a variety of solvents. Almost all the polymers could be dissolved in N‐methyl‐2‐pyrrolidinone, N,N‐dimethylacetamide (DMAc), N,N‐dimethylformamide, dimethyl sulfoxide, pyridine, and even in tetrahydrofuran and cyclohexanone. These polymers showed glass‐transition temperatures between 223 and 256 °C and decomposition temperatures at 10% weight loss ranging from 468 to 491 °C and 469 to 498 °C in nitrogen and air atmospheres, respectively. Transparent, tough, and flexible films of these polymers were cast from the DMAc solutions. These polymer films had tensile strengths ranging from 76 to 99 MPa, elongations at break from 7 to 19%, and initial moduli from 2.1 to 2.7 GPa. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 797–803, 2000     

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 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     

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     

Preparation and properties of aromatic polyamides from 1,4-bis(p-carboxyphenoxy)naphthyl and aromatic diamines

A new aromatic dicarboxylic acid, 1,4-bis (p-carboxyphenoxy)naphthyl ( 3 ), was synthesized by the reaction of p-fluorobenzonitrile with 1,4-naphthalenediol, followed by hydrolysis. Aromatic polyamides having inherent viscosities of 1.27–2.22 dL/g were prepared by the triphenyl phosphite activated polycondensation of diacid 3 with various aromatic diamines. Most of the resulting polymers showed an amorphous nature and were readily soluble in a variety of organic solvents including N,N-dimethyl-acetamide (DMAc), N-methyl-2-pyrrolidone (NMP), and m-cresol. Transparent, tough, and flexible films of these polymers could be cast from the DMAc or NMP solutions. The cast films had tensile strengths ranging from 64–104 MPa, elongations-at-break from 6 to 10%, and initial moduli from 1.52 to 2.14 GPa. These polyamides had glass transition temperatures in the range of 195 to 240°C. Almost all polymers were thermally stable up to 400°C, with 10% weight loss being recorded above 480°C in air and nitrogen atmospheres. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 2273–2280, 1997     

Synthesis and properties of new organo‐soluble and strictly alternating aromatic poly(ester‐imide)s from 3,3‐bis[4‐(trimellitimidophenoxy)phenyl]phthalide and bisphenols

A series of new strictly alternating aromatic poly(ester‐imide)s having inherent viscosities of 0.20–0.98 dL/g was synthesized by the diphenylchlorophosphate (DPCP) activated direct polycondensation of the preformed imide ring‐containing diacid, 3,3‐bis[4‐(trimellitimidophenoxy)phenyl]phthalide (I), with various bisphenols in a medium consisting of pyridine and lithium chloride. The diimide–diacid I was prepared from the condensation of 3,3‐bis[4‐(4‐aminophenoxy)phenyl]phthalide and trimellitic anhydride. Most of the resulting polymers showed an amorphous nature and were readily soluble in a variety of organic solvents such as N‐methyl‐2‐pyrrolidone (NMP) and N,N‐dimethylacetamide (DMAc). Transparent and flexible films of these polymers could be cast from their DMAc solutions. The cast films had tensile strengths ranging 66–105 MPa, elongations at break from 7–10%, and initial moduli from 1.9–2.4 GPa. The glass‐transition temperatures of these polymers were recorded between 208–275 °C. All polymers showed no significant weight loss below 400 °C in the air or in nitrogen, and the decomposition temperatures at 10% weight loss all occurred above 460 °C. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1090–1099, 2000     

1,4‐Addition polymerization of 1,4‐bis(4‐benzylpyridinium)butadiyne triflate in a dipolar aprotic solvent

1,4‐Bis(4‐benzylpyridinium)butadiyne triflate was aggregated in dimethylformamide and spontaneously converted into the 1,4‐addition type of polydiacetylene. The polymerization took place in a dipolar aprotic solvent with a large dielectric constant that could enhance the aggregation of the ionic diacetylene salt through the electrostatic interaction. The molecular weight of the diacetylene was leveled off after 30 h at 80 °C to reach 1.5 × 10⁴ (number‐average molecular weight) that consisted of the 1,4‐addition type of polydiacetylene similar to polydiacetylenes obtained in the conventional solid‐state polymerization. Electron spin resonance spectra revealed that diradicals were generated at the earlier state aggregation to give rise to a solution polymerization. The UV spectra also suggested the presence of the activated aggregation associated with the polymerization as well as the eximer emission spectra. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3534–3541, 2002     

Synthesis and nonlinear properties of poly[1,4‐bis(4‐alkylpyridinium)butadiyne triflate]

1,4‐Bis(4‐alkylpyridinium)butadiyne triflate ( 2a and 2b ) that was prepared by the reaction of 1,4‐bis(4‐pyridyl)butadiyne ( 1 ) with alkyl trifluoro‐methanesulfonate, was found to grow into a large crystal as a result of the quaternized structure. The thermal treatment of 2a and 2b gave rise to 1,4‐addition polymerization to yield the polydiacetylene. The third‐order nonlinear optical susceptibility [χ⁽³⁾] of the polymer was determined by the femto‐second Z‐scan method to exhibit the remarkable high value of 1.1 × 10^?11 esu at 650 nm. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3686–3691, 2001     

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 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 properties of fluorinated polyimides based on 1,4‐bis(4‐amino‐2‐trifluoromethylphenoxy)‐2,5‐di‐tert‐butylbenzene and various aromatic dianhydrides

A novel fluorinated diamine monomer, 1,4‐bis(4‐amino‐2‐trifluoromethylphenoxy)‐2,5‐di‐tert‐butylbenzene ( 2 ), was prepared through the nucleophilic substitution reaction of 2‐chloro‐5‐nitrobenzotrifluoride and 2,5‐di‐tert‐butylhydroquinone in the presence of potassium carbonate, followed by catalytic reduction with hydrazine and Pd/C. Fluorinated polyimides ( 5a – 5f ) were synthesized from diamine 2 and various aromatic dianhydrides ( 3a – 3f ) via thermal or chemical imidization. These polymers had inherent viscosities of 0.77–1.01 dL/g. The 5 series polyimides were soluble in N‐methyl‐2‐pyrrolidone, N,N‐dimethylacetamide, and N,N‐dimethylformamide and were even soluble in dioxane, tetrahydrofuran, and dichloromethane. 5 (C) showed cutoff wavelengths between 363 and 404 nm and yellowness index (b*) values of 6.5–40.2. The polyimide films had tensile strengths of 93–114 MPa, elongations to break of 9–12%, and initial moduli of 1.7–2.1 GPa. The glass‐transition temperatures were 255–288 °C. The temperatures of 10% weight loss were all above 460 °C in air or nitrogen atmospheres. In comparison with a nonfluorinated polyimide series based on 1,4‐bis(4‐aminophenoxy)‐2,5‐di‐tert‐butylbenzene, the 5 series showed better solubility and lower color intensity, dielectric constants, and moisture absorption. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2272–2284, 2004     

Synthesis and properties of ortho‐linked aromatic polyimides based on 1,2‐bis(4‐aminophenoxy)‐4‐tert‐butylbenzene

A bis(ether amine) containing the ortho‐substituted phenylene unit and pendant tert‐butyl group, 1,2‐bis(4‐aminophenoxy)‐4‐tert‐butylbenzene, was synthesized and used as a monomer to prepare polyimides with six commercial dianhydrides via a conventional two‐stage procedure. The intermediate poly(amic acid)s had inherent viscosities of 0.78–1.44 dL/g, and most of them could be thermally converted into transparent, flexible, and tough polyimide films. The inherent viscosities of the resulting polyimides were in the range of 0.46–0.87 dL/g. All polyimides were noncrystalline, and most of them showed excellent solubility in polar organic solvents. The glass‐transition temperatures of these polyimides were in the range of 222–259 °C in differential scanning calorimetry and 212–282 °C in thermomechanicl analysis. These polyimides showed no appreciable decomposition up to 500 °C in thermogravimetric analysis in air or nitrogen. A comparative study of the properties with the corresponding polyimides without pendant tert‐butyl groups derived from 1,2‐bis(4‐aminophenoxy)benzene is also presented. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1551–1559, 2000     

基于二芳炔硫醚的2,6-二芳基-1,4-二噻烯的合成

描述了一种基于二芳炔硫醚(Ar—C≡C—S—C≡C—Ar)底物合成2,6-二芳基-1,4-二噻烯的方法.将二芳炔硫醚和Na2S·9H2O在C2H5OH/C2H5ONa体系中回流反应,以80%~96%的产率合成了一系列2,6-二芳基-1,4-二噻烯化合物.该方法反应条件温和、产率高并且表现出很好的选择性.反应机理涉及硫负离子对底物分子的两个C≡C键的选择性亲核加成,即硫负离子(包括S2-和中间体B硫负离子)总是选择性地加到芳基一侧的炔碳上形成1,4-二噻烯.对化合物1a进行了X线晶体结构解析.分子中的六元杂环呈"船式"构型.C(1)—C(2)和C(1A)—C(2A)具有典型的双键性质,S(1)—C(2)和S(2)—C(1)的键长数则比一般C—S单键稍短,显示硫原子上的孤对电子与C(1)=C(2)双键上的π电子存在一定程度的共轭作用.1a的晶体学参数:属正交晶系,Pnma空间群,a=10.1330(11),b=27.318(3),c=5.5402(6),α=90.00°,β=90.00°,γ=90.00°,V=1533.6(3)3,Z=4,ρcalcd=1.422 g/cm3.最终偏离因子R=0.038,Rw=0.102。     

Synthesis and characterization of novel polyarylates from 2,5-bis(4-hydroxyphenyl)-3,4-diphenylpyrrole and various aromatic dicarboxylic acids

A new tetraphenylated heterocylic diol, 2,5-bis(4-hydroxyphenyl)-3,4-diphenylpyrrole, was synthesized in three steps starting from 4-methoxydeoxybenzoin. The tetraphenylpyrrole-containing polyarylates having inherent viscosities of 0.28–0.88 dL/g were prepared from the diol and various aromatic dicarboxylic acid chlorides by both phase transfer catalyzed two-phase polycondensation and high temperature solution polymerization methods. All the polyarylates were semi-crystalline, and were readily soluble in a variety of solvents including N-methyl-2-pyrrolidone, m cresol, pyridine, and 1,4-dioxane. These polymers had glass transition temperatures in the range of 223–279°C, with no weight loss below 400°C in both air and nitrogen atmospheres. © 1994 John Wiley & Sons, Inc.     

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     

Structure and Photosynthetic Mimicking of Bis（2,6—bis（benzimidazol—2—yl）pyridine）manganese（Ⅱ）

Mn(bzimpy)2(1)[bzimpy=2,6-bis(benzimidazol-2-yl)pyridine],a mononuclear manganese(Ⅱ）complex,was synthesized by the reaction of Mn(OOCMe)2 with bzimpy in absolute ethanol.The complex was structurally characterized by elemental analysis,cyclic voltammetry,and X-ray crystallography.In the complex,the manganese-nitrogen distances were different,and the geometry and the metal ion environment showed the distortion.The cyclic voltammetric measurements have been performed to assess its redox characteristics.The presence of oxidation wave at 0.62V and 0.081V vs.SCE or 0.8V and 1.0v vs.NHE suggested that this complex could catalyze the oxidation of water,therefore,simulate the water-oxidizing complex(WOC) of photosystem Ⅱ (PS Ⅱ).The measurements of photoreduction of 2,6-dichlorophenolindophenol (DCPIP),and oxygen evolution in the manganess-depleted and the comples 1-reconstituted PS Ⅱ preparations just support our conjecture.     

Structural Diversity in the Self‐assembly of Cd(II) Complexes Containing 2,6‐Dimethyl‐3,5‐dicyano‐4‐(4‐pyridyl)‐1,4‐dihydropyridine

The syntheses, structures and properties of the complexes [CdBr₂( L )₂·4H₂O]_n [ L = 2,6‐dimethyl‐3,5‐dicyano‐4‐(4‐pyridyl)‐1,4‐dihydropyridine], 1 and [Cd(SCN)₂( L )₂(H₂O)]_n, 2 , are reported. In polymeric complexes 1 — 2 , the L ligands bridge the metal centers through the pyrimidyl and cyano nitrogen atoms forming 1‐D double‐stranded chain and zigzag chain, respectively. The L ligands in complex 1 act as κ1, κ1‐bidentate bridging ligand, whereas the L ligands in complex 2 act as κ1‐monodentae and κ1, κ1‐bidentate bridging ligand. The molecules of these complexes are interlinked through various weak interactions that form the packed structure. All the complexes exhibit emissions which may be tentatively assigned as intraligand (IL) π→π* transitions.     

A thermally stable three‐dimensional cobalt(II) coordination polymer based on the V‐shaped ligand 4‐(4‐carboxyphenoxy)isophthalate

A new cobalt(II) coordination polymer (CP), poly[[bis[μ₆‐4‐(4‐carboxylatophenoxy)benzene‐1,3‐dicarboxylato‐κ⁶O¹:O¹:O³:O^3′:O⁴:O^4′]bis(1,10‐phenanthroline‐κ²N,N′)tricobalt(II)] 0.72‐hydrate], {[Co₃(C₁₅H₇O₇)₂(C₁₂H₈N₂)₂]·0.72H₂O}_n, (I), is constructed from Co^II ions and 4‐(4‐carboxyphenoxy)isophthalate (cpoia³⁻) and 1,10‐phenanthroline (phen) ligands. Based on centrosymmetric trinuclear [Co₃(phen)₂(COO)₆] secondary building units (SBUs), the structure of (I) is a three‐dimensional CP with a (3,6)‐connected net and point symbol (4².6)₂(4⁴.6².8⁷.10²). The positions of four [Co₃(phen)₂(COO)₆] SBUs and four cpoia³⁻ ligands reproduce a Chinese‐knot‐shaped arrangement along the ab plane. (I) has been characterized by single‐crystal X‐ray diffraction, IR spectroscopy, powder X‐ray diffraction (PXRD) and thermostability analysis. It shows a good thermal stability from room temperature to 673 K. In addition, the temperature dependence of the magnetic properties was measured.     

Synthesis and properties of new aromatic polyimides based on 2,5‐bis(4‐amino‐2‐trifluoromethylphenoxy)‐tert‐butylbenzene and various aromatic dianhydrides

A novel, fluorinated diamine monomer, 2,5‐bis(4‐amino‐2‐ trifluoromethylphenoxy)‐tert‐butylbenzene ( II ) was synthesized through the nucleophilic substitution reaction of tert‐butylhydroquinone (t‐BHQ) and 2‐chloro‐5‐nitrobenzotrifluoride in the presence of potassium carbonate to yield the intermediate dinitro compound I , followed by catalytic reduction with hydrazine and Pd/C to afford diamine II . A series of fluorinated polyimides V were prepared from II with various aromatic dianhydrides ( III _a–f ) via the thermal imidization of poly(amic acid). Most of V _a–f could be soluble in amide‐type solvents and even in less polar solvents. These polyimide films showed tensile strengths up to 106 MPa, elongation at break up to 21%, and initial modulus up to 2.1 GPa. The glass‐transition temperature of V was recorded at 245–304 °C, the 10% weight loss temperatures were above 488 °C, and left more than 41% residue even at 800 °C in nitrogen. Low dielectric constants, low moisture absorptions, and higher and light‐colored transmittances were also observed. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5424–5438, 2004     

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

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