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 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 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     

Synthesis and properties of soluble trifluoromethyl‐substituted polyimides containing laterally attached p‐Terphenyls

A new fluorinated diamine monomer, 2′,5′‐bis(4‐amino‐2‐trifluoromethylphenoxy)‐p‐terphenyl, was synthesized from the chloro‐displacement of 2‐chloro‐5‐nitrobenzotrifluoride with the potassium phenolate of 2,5‐diphenylhydroquinone, followed by hydrazine palladium‐catalyzed reduction. A series of trifluoromethyl‐substituted polyimides containing flexible ether linkages and laterally attached side rods were synthesized from the diamine with various aromatic dianhydrides via a conventional two‐step process. The inherent viscosities of the poly(amic acid) precursors were 0.84–1.26 dL/g. All the polyimides afforded flexible and tough films. The use of 4,4′‐oxydiphthalic anhydride and 2,2′‐bis(3,4‐dicarboxyphenyl)hexafluoropropane dianhydride produced essentially colorless polyimide films. Most of the polyimides revealed an excellent solubility in many organic solvents. The glass‐transition temperatures of these polyimides were recorded between 254 and 299 °C by differential scanning calorimetry, and the softening temperatures of the polymer films stayed in the range of 253–300 °C according to thermomechanical analysis. The polyimides did not show significant decomposition before 500 °C in air or under nitrogen. These polyimides also showed low dielectric constants (2.83–3.34 at 1 MHz) and low moisture absorption (0.4–2.2%). For a comparative study, a series of analogous polyimides based on the nonfluorinated diamine 2′,5′‐bis(4‐aminophenoxy)‐p‐terphenyl were also prepared and characterized. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1255–1271, 2004     

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 properties of fluorinated polyimides. 1. Derived from novel 4,4″‐bis(aminophenoxy)‐3,3″‐trifluoromethyl terphenyl

A new diamine monomer, 4,4″‐bis(aminophenoxy)‐3,3″‐trifluoromethyl terphenyl (ATFT) was synthesized that led to a number of novel fluorinated polyimides by solution as well as thermal imidization routes when reacted with different commercially available dianhydrides like pyromellatic dianhydride (PMDA), benzophenone tetracarboxylic acid dianhydride (BTDA), or 2,2‐bis(3,4‐dicarboxyphenyl) hexafluoropropane (6FDA). The polyimides ATFT/BTDA and ATFT/6FDA derived from both routes were soluble in several organic solvents such as N,N‐dimethylformamide, N,N‐dimethylacetamide, and dimethyl sulfoxide. The polyimide ATFT/PMDA was only soluble in N‐methylpyrollidone. The polyimide films had low water absorption of 0.3–0.7%, low dielectric constants of 2.72–3.3 at 1 Hz, refractive indices of 1.594–1.647 at 589.3 nm, and optical transparency >85%. These polyimides showed very high thermal stability with decomposition temperatures (5% weight loss) up to 532 °C in air and good isothermal stability; only 7% weight loss occurred at 400 °C after 7 h, and less than 0.6% weight loss was observed at 315 °C for 5 h. Transparent thin films of these polyimides exhibited tensile strengths up to 112 MPa, a modulus of elasticity up to 3.05 GPa, and elongation at break up to 21% depending on the repeating unit structure. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1016–1027, 2002     

Preparation and properties of new polyimides and polyamides based on 1,4‐bis(4‐amino‐2‐trifluoromethylphenoxy)naphthalene

A novel, trifluoromethyl‐substituted, bis(ether amine) monomer, 1,4‐bis(4‐amino‐2‐trifluoromethylphenoxy)naphthalene, was synthesized through the nucleophilic displacement of 2‐chloro‐5‐nitrobenzotrifluoride with 1,4‐dihydroxynaphthalene in the presence of potassium carbonate in dimethyl sulfoxide, followed by catalytic reduction with hydrazine and Pd/C in ethanol. A series of new fluorine‐containing polyimides with inherent viscosities of 0.57–0.91 dL/g were prepared by reacting the diamine with six commercially available aromatic dianhydrides via a conventional, two‐step thermal or chemical imidization method. Most of the resulting polyimides were soluble in strong polar solvents such as N‐methylpyrrolidone and N,N‐dimethylacetamide (DMAc). All the polyimides afforded transparent, flexible, and strong films with good tensile properties. These polyimides exhibited glass‐transition temperatures (T_g's) (by DSC) and softening temperatures (by thermomechanical analysis) in the ranges of 252–315 and 254–301 °C, respectively. Decomposition temperatures for 5% weight loss all occurred above 500 °C in both air and nitrogen atmospheres. The dielectric constants of these polyimides ranged from 3.03 to 3.71 at 1 MHz. In addition, a series of new, fluorinated polyamides with inherent viscosities of 0.32–0.62 dL/g were prepared by the direct polycondensation reaction the diamine with various aromatic dicarboxylic acids by means of triphenyl phosphite and pyridine. All the polyamides were soluble in polar solvents such as DMAc and could be solution‐cast into tough and flexible films. These polyamides had T_g's between 228 and 256 °C and 10% weight‐loss temperatures above 400 °C in nitrogen or air. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2377–2394, 2004     

Highly organosoluble and flexible polyimides with color lightness and transparency based on 2,2‐bis[4‐(2‐trifluoromethyl‐4‐aminophenoxy)‐3,5‐dimethylphenyl]propane

A new diamine containing isopropylidene, methyl substituted arylene ether, and trifluoromethyl groups, 2,2‐bis[4‐(2‐trifluoromethyl‐4‐aminophenoxy)‐3,5‐dimethylphenyl]propane (BTADP), was synthesized and used in preparation of a series of polyimides by direct polycondensation with various aromatic tetracarboxylic dianhydrides in N, N‐dimethylacetamide (DMAc). All polymers derived from diamine (BTADP) with trifluoromethyl substituents were highly organosoluble in the solvents, like N‐methyl‐2‐pyrrolidinone (NMP), N,N‐dimethylacetamide, N,N‐dimethylformamide (DMF), pyridine, chloroform, tetrahydrofuran (THF), dimethyl sulfoxide (DMSO), dichloromethane, cyclohexanone, and γ‐butyrolactone at room temperature or upon heating at 70 °C. Inherent viscosities of the polyimides were found to range between 0.58 and 0.97 dL·g^?1. These polyimides had glass transition temperatures between 256 and 307 °C, and their 10% mass loss temperatures ranged from 440 to 462 °C and 421 to 443 °C under nitrogen and air, respectively. These polyimides had low dielectric constants in the range of 2.84–3.09. All the polyimides could be cast into films from DMAc solutions and were thermally converted into color lightness, optically transparent, flexible, and tough polyimides. The polyimide films had a tensile strength in the range of 83–97 MPa and a tensile modulus in the range of 2.0–2.2 GPa. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5766–5774, 2004     

Synthesis and characterization of new soluble aromatic polyamides derived from 1,4‐Bis(4‐carboxyphenoxy)‐2, 5‐di‐tert‐butylbenzene

Aromatic polyamides based on a novel bis(ether‐carboxylic acid) were synthesized by the direct phosphorylation condensation method. 1,4‐Bis(4‐carboxyphenoxy)‐2,5‐di‐tert‐butylbenzene was combined with various diamines containing flexible linkages and side substituents to render a set of eight novel aromatic polyamides. The polymers were produced with high yields and moderate to high inherent viscosities (0.49–1.32 dL/g) that corresponded to weight‐average and number‐average molecular weights (by gel permeation chromatography) of 31,000–80,000 and 19,000–50,000, respectively. Except for a single example, the polyamides were essentially amorphous and soluble in a variety of common solvents such as cyclohexanone, dioxane, and tetrahydrofuran. They showed glass‐transition temperatures of 250–295 °C (by differential scanning calorimetry) and 10% weight loss temperatures above 460 °C, as revealed by thermogravimetric analysis in nitrogen. Polymer films, obtained by casting from N,N‐dimethylacetamide solutions, exhibited good mechanical properties, with tensile strengths of 83–111 MPa and tensile moduli of 2.0–2.2 GPa. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 475–485, 2001     

Novel,organosoluble, light‐colored fluorinated polyimides based on 2,2′‐bis(4‐amino‐2‐trifluoromethylphenoxy)biphenyl or 2,2′‐bis(4‐amino‐2‐trifluoromethylphenoxy)‐1,1′‐binaphthyl

Two series of fluorinated polyimides were prepared from 2,2′‐bis(4‐amino‐2‐trifluoromethylphenoxy)biphenyl ( 2 ) and 2,2′‐bis(4‐amino‐2‐trifluoromethylphenoxy)‐1,1′‐binaphthyl ( 4 ) with various aromatic dianhydrides via a conventional, two‐step procedure that included a ring‐opening polyaddition to give poly(amic acid)s, followed by chemical or thermal cyclodehydration. The inherent viscosities of the polyimides ranged from 0.54 to 0.73 and 0.19 to 0.36 dL/g, respectively. All the fluorinated polyimides were soluble in many polar organic solvents, such as N,N‐dimethylacetamide and N‐methylpyrrolidone, and afforded transparent and light‐colored films via solution‐casting. These polyimides showed glass‐transition temperatures in the ranges of 222–280 and 257–351 °C by DSC, softening temperatures in the range of 264–301 °C by thermomechanical analysis, and a decomposition temperature for 10% weight loss above 520 °C both in nitrogen and air atmospheres. The polyimides had low moisture absorptions of 0.23–0.58%, low dielectric constants of 2.84–3.61 at 10 kHz, and an ultraviolet–visible absorption cutoff wavelength at 351–434 nm. Copolyimides derived from the same dianhydrides with an equimolar mixture of 4,4′‐oxydianiline and diamine 2 or 4 were also prepared and characterized. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2416–2431, 2004     

Organosoluble and light‐colored fluorinated polyimides from 4,4′‐bis(4‐amino‐2‐trifluoromethylphenoxy)biphenyl and aromatic dianhydrides

A novel fluorinated diamine monomer based on 4,4′‐biphenol was synthesized via a straightforward, high‐yielding two‐step procedure. 4,4′‐Biphenol was reacted with 2‐chloro‐5‐nitrobenzotrifluoride in the presence of potassium carbonate to yield the intermediate dinitro compound, which was subsequently reduced to afford the fluorinated diamine, 4,4′‐bis(4‐amino‐3‐trifluoromethylphenoxy)biphenyl. A series of organosoluble fluorinated polyimides were prepared from the diamine with various aromatic dianhydrides via a conventional two‐step thermal imidization method. All polyimides were soluble in strong dipolar solvents such as N‐methyl‐2‐pyrrolidone and N,N‐dimethylacetamide. The polyimides showed excellent thermal and thermooxidative stability and good mechanical properties. No significant weight loss was observed below a temperature of 520 °C in nitrogen or in air, and the glass‐transition temperatures ranged from 247 to 313 °C. Low dielectric constants (2.57–3.65 at 10 kHz), low moisture absorption (0.1–0.7 wt %), and low color intensity were also observed. © 2002 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 524–534, 2002; DOI 10.1002/pola.10113     

Structural investigation of one‐ and two‐dimensional coordination polymers based on cobalt–bis(dioxolene) units and 1‐hydroxy‐1,2,4,5‐tetrakis(pyridin‐4‐yl)cyclohexane

The combination of cobalt, 3,5‐di‐tert‐butyldioxolene (3,5‐dbdiox) and 1‐hydroxy‐1,2,4,5‐tetrakis(pyridin‐4‐yl)cyclohexane (tpch) yields two coordination polymers with different connectivities, i.e. a one‐dimensional zigzag chain and a two‐dimensional sheet. Poly[[bis(3,5‐di‐tert‐butylbenzene‐1,2‐diolato)bis(1,5‐di‐tert‐butyl‐4‐oxocyclohexa‐2,5‐dien‐1‐yl‐3‐olato)[μ₄‐1‐hydroxy‐1,2,4,5‐tetrakis(pyridin‐4‐yl)cyclohexane]cobalt(III)]–ethanol–water 1/7/5], {[Co₂(C₁₄H₂₀O₂)₄(C₂₆H₂₄N₄O)]·7C₂H₅OH·5H₂O}_n or {[Co₂(3,5‐dbdiox)₄(tpch)}·7EtOH·5H₂O}_n, is the second structurally characterized example of a two‐dimensional coordination polymer based on linked {Co(3,5‐dbdiox)₂} units. Variable‐temperature single‐crystal X‐ray diffraction studies suggest that catena‐poly[[[(3,5‐di‐tert‐butylbenzene‐1,2‐diolato)(1,5‐di‐tert‐butyl‐4‐oxocyclohexa‐2,5‐dien‐1‐yl‐3‐olato)cobalt(III)]‐μ‐1‐hydroxy‐1,2,4,5‐tetrakis(pyridin‐4‐yl)cyclohexane]–ethanol–water (1/1/5)], {[Co(C₁₄H₂₀O₂)₂(C₂₆H₂₄N₄O)]·C₂H₅OH·5H₂O}_n or {[Co(3,5‐dbdiox)₂(tpch)]·EtOH·5H₂O}_n, undergoes a temperature‐induced valence tautomeric interconversion.     

Synthesis and properties of polyimides derived from 1,4-bis(4-aminophenoxy)2,5-di-tert-butylbenzene

Novel aromatic polyimides containing symmetric, bulky di-tert-butyl substituents unit were synthesized from 1,4-bis(4-aminophenoxy)2,5-di-tert-butylbenzene (BADTB) and various aromatic tetracarboxylic dianhydrides by the conventional two-stage procedure that included ring-opening polyaddition in a polar solvent such as N,N-dimethylacetamide to give poly(amic acid)s, followed by cyclodehydration to polyimides. The diamine was prepared through the nucleophilic displacement of 2,5-di-tert-butylhydroquinone with p-chloronitrobenzene in the presence of K₂CO₃, followed by catalytic reduction. Depending on the dianhydrides used, the poly(amic acid)s obtained had inherent viscosities of 0.83–1.88 dL g⁻¹. Most of the polyimides formed transparent, flexible, and tough films. Tensile strength and elongation at break of the BADTB-based polyimide films ranged from 68–93 MPa and 7–11%, respectively. The polyimide derived from 4,4′-hexafluoro-isopropylidenebisphathalic anhydride had better solubility than the other polyimides. These polyimides had glass transition temperatures between 242–298°C and 10% mass loss temperatures were recorded in the range of 481–520°C in nitrogen. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1527–1534, 1997     

High Tg and high organosolubility of novel unsymmetric polyimides

A series of new polyimides (PIs) containing di‐tert‐butyl side groups were synthesized via a polycondensation of 1‐(4‐aminophenoxy)‐4‐(4‐amino‐2‐methylphenyl)‐2,6‐di‐tert‐butylbenzene ( 3 ) with various aromatic tetracarboxylic dianhydrides. The novel unsymmetric PIs exhibited a low dielectric constants (2.78–3.02), low moisture absorption (0.53–1.35%), excellent solubility, and high glass transition temperature (308–450 °C). The PI derived from the new diamine and the very rigid naphthalene‐1,4,5,8‐tetracarboxylic dianhydride (NTDA) was soluble in N‐methyl‐2‐pyrrolidone, chloroform, m‐cresol, and cyclohexanone. The unsymmetric di‐tert‐butyl pendent groups significantly enhance the rotational barrier of the polymer chains; thus these PIs had high T_gs. The ¹H NMR spectrum of the diamine 3 revealed that the protons of 4‐aminophenoxy moiety are not chemical shift equivalent. This is because the steric hindrance of the bulky di‐tert‐butyl groups prevents the benzene ring of 4‐aminophenoxy moiety from rotating freely. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2443–2452, 2009     

Preparation and properties of molecular‐weight‐controlled polyimides derived from 1,4‐bis(4′‐amino‐2′‐trifluoromethylphenoxy)benzene and 4,4′‐oxydiphthalic anhydride

A series of molecular‐weight‐controlled fluorinated aromatic polyimides were synthesized through the polycondensation of a fluorinated aromatic diamine, 1,4‐bis(4′‐amino‐2′‐trifluoromethylphenoxy)benzene, with 4,4′‐oxydiphthalic anhydride in the presence of phthalic anhydride as the molecular‐weight‐controlling and end‐capping agent. Experimental results demonstrated that the resulting polyimides could melt at temperatures of 250–300 °C to give high flowing molten fluids, which were suitable for melt molding to give strong and flexible polyimide sheets. Moreover, the aromatic polyimides also showed good solubility both in polar aprotic solvents and in common solvents. Polyimide solutions with solid concentrations higher than 25 wt % could be prepared with relatively low viscosity and were stable in storage at the ambient temperature. High‐quality polyimide films could be prepared via the casting of the polyimide solutions onto glass plates, followed by baking at a relatively low temperature. The molten behaviors and organosolubility of the molecular‐weight‐controlled aromatic polyimides depended significantly on the polymer molecular weights. Both the melt‐molded polyimide sheets and the solution‐cast polymer films exhibited outstanding combined mechanical and thermal properties. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1997–2006, 2006     

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

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

Highly soluble fluorinated polyimides based on an asymmetric bis(ether amine): 1,7‐bis(4‐amino‐2‐trifluoromethylphenoxy)naphthalene

A novel structurally asymmetric bis(ether amine) monomer containing trifluoromethyl groups, 1,7‐bis(4‐amino‐2‐trifluoromethylphenoxy)naphthalene, was prepared through the nucleophilic substitution reaction of 2‐chloro‐5‐nitrobenzotrifluoride and 1,7‐dihydroxynaphthalene in the presence of potassium carbonate in N‐methyl‐2‐pyrrolidone (NMP), followed by catalytic reduction with hydrazine and Pd/C in ethanol. A series of new fluorine‐containing polyimides were synthesized from the diamine with various commercially available aromatic tetracarboxylic dianhydrides using a two‐stage process with thermal or chemical imidization method. The intermediate poly(amic acid)s had inherent viscosities between 0.93 and 1.93 dL/g. Most of the polyimides obtained from both routes were readily soluble in many organic solvents such as NMP and N,N‐dimethylacetamide (DMAc). All the polyimides could afford transparent, flexible, and strong films with low moisture absorptions of 0.29–0.69%, low dielectric constants of 2.81–3.23 at 10 kHz, and an ultraviolet‐visible absorption cutoff wavelength at 358–423 nm. The glass‐transition temperatures (T_gs) (by DSC) and softening temperatures (by thermomechanical analysis) of the polyimides were recorded in the range of 222–271 °C and 210–266 °C, respectively. Decomposition temperatures for 10% weight loss all occurred above 500 °C in both nitrogen and air atmospheres. For a comparative study, some properties of the present polyimides will be compared with those of structurally related ones derived from 1,7‐bis(4‐aminophenoxy)naphthalene and 1,5‐bis(4‐amino‐2‐trifluoromethylphenoxy)naphthalene. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1756–1770, 2009     

Novel aromatic polyamides and polyimides functionalized with 4‐tert‐butyltriphenylamine groups

A new triphenylamine‐containing diamine monomer, 4,4′‐diamino‐4″‐tert‐butyltriphenylamine, was successfully synthesized by the cesium fluoride‐mediated N,N‐diarylation of 4‐tert‐butylaniline with 4‐fluoronitrobenzene, followed by the reduction of the nitro group. The obtained diamine monomer was reacted with various aromatic dicarboxylic acids and tetracarboxylic dianhydrides to produce two series of novel triphenylamine‐based polyamides and polyimides with pendent tert‐butyl substituents. Most of the polymers were readily soluble in polar organic solvents, such as N‐methyl‐2‐pyrrolidone and N,N‐dimethylacetamide (DMAc), and could be solution cast into tough and flexible polymer films. These polymers showed high glass transition temperatures between 282 and 320 °C, and they were fairly stable up to a temperature above 450 °C (for polyamides) or 500 °C (for polyimides). These polymers exhibited UV absorption maxima around 308 to 361 nm. The photoluminescence spectra of the polyamides in DMAc exhibited a peak emission wavelength in the blue at 421–433 nm. Cyclic voltammograms of polyamides and polyimides showed an oxidation wave at 1.0–1.1 V versus Ag/AgCl in an acetonitrile solution. All the polyamides and polyimides exhibited excellent reversibility of electrochromic characteristics by continuous several cyclic scans between 0.0 and 1.1–1.3 V, with a color change from the original pale yellowish neutral form to the green or blue oxidized forms. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4579–4592, 2006     

Enhanced redox stability and electrochromic properties of aromatic polyamides based on N,N‐bis(4‐carboxyphenyl)‐N′,N′‐bis(4‐tert‐butylphenyl)‐1,4‐phenylenediamine

A new bis(triphenylamine)‐type dicarboxylic acid monomer, N,N‐bis(4‐carboxyphenyl)‐N′,N′‐bis(4‐tert‐butylphenyl)‐1,4‐phenylenediamine, was prepared by a well‐established procedure and led to a new family of redox‐active aromatic polyamides with di‐tert‐butyl‐substituted N,N,N′,N′‐tetraphenylphenylenediamine (TPPA) segments. The resulting polyamides were amorphous with good solubility in many organic solvents, and most of them could be solution cast into flexible polymer films. The polyamides exhibited high thermal stability with glass‐transition temperatures in the range of 247–293 °C and 10% weight‐loss temperatures in excess of 500 °C. They showed well‐defined and reversible redox couples during oxidative scanning, with a strong color change from a colorless or pale yellowish neutral form to green and blue oxidized forms. They had enhanced redox stability and electrochromic performance when compared with the corresponding analogs without tert‐butyl substituents on the TPPA unit. The polyamide with TPPA units in both the diacid and diamine components shows multicolored electrochromic behavior. A polyamide containing both the cathodic coloring anthraquinone chromophore and the anodic coloring TPPA chromophore has the ability to show red, green, and blue states, toward single‐component RGB electrochromics. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Synthesis and properties of polyimides derived from 1,4‐bis(4‐aminophenoxy)‐2‐(6‐oxido‐6H‐dibenz[c,e] [1,2]oxaphosphorin‐6‐yl) phenylene

A new phosphorus‐containing aromatic diamine, 1,4‐bis(4‐aminophenoxy)‐2‐(6‐oxido‐6H‐dibenz[c,e] [1,2]oxaphosphorin‐6‐yl) phenylene ( 3 ) was synthesized by the nucleophilic aromatic substitution of 2‐(6‐oxido‐6H‐dibenz[c,e] [1,2]oxaphosphorin‐6‐yl)‐1,4‐dihydroxy phenylene ( 1 ) with 4‐fluoronitrobenzene, followed by catalytic hydrogenation. Light color, flexible, and creasable polyimides with high molecular weight, high glass transition, high thermal stability, improved organosolubility, and good oxygen plasma resistance were synthesized from the condensation of ( 3 ) with various aromatic dianhydrides in N,N‐dimethylacetamide, followed by thermal imidization. The number‐average molecular weights of polyimides are in the range of 7.0–8.3 × 10⁴ g/mol, and the weight‐average molecular weights are in the range of 12.5–16.5 × 10⁴ g/mol. The T_gs of these polyimides range from 230 to 304 °C by differential scanning calorimetry and from 228 to 305 °C by DMA. These polyimides are tough and flexible, with tensile strength at around 100 MPa. The degradation temperatures (T_d 5%) and char yields at 800 °C in nitrogen range from 544 to 597 °C and 59–65 wt %, respectively. Polyimides 5c and 5e , derived from OPDA and 6FDA, respectively, with the cutoff wavelength of 347 and 342 μm, respectively, show very light color. These polyimides also exhibit good oxygen plasma resistance. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2897–2912, 2007