Synthesis,photoluminescence, and electrochromic properties of wholly aromatic polyamides bearing naphthylamine chromophores

A series of novel polyamides with pendent naphthylamine units having inherent viscosities of 0.15–1.02 dL/g were prepared via direct phosphorylation polycondensation from various diamines and a naphthylamine‐based aromatic dicarboxylic acid, 1‐[N,N‐di(4‐carboxyphenyl)amino]naphthalene. These amorphous polyamides were readily soluble in various organic solvents and could be cast into transparent and tough films. The aromatic polyamides had useful levels of thermal stability associated with high glass‐transition temperatures (268–355 °C), 10% weight loss temperatures in excess of 480 °C, and char yields at 800 °C in nitrogen higher than 60%. These polymers showed maximum ultraviolet–visible absorption at 350–358 nm and exhibited fluorescence emission maxima around 435–458 nm in N‐methyl‐2‐pyrrolidinone solutions with fluorescence quantum yields ranging from 0.4 to 15.0%. The hole‐transporting and electrochromic properties were examined with electrochemical and spectroelectrochemical methods. Cyclic voltammograms of the polyamide films cast onto an indium tin oxide coated glass substrate exhibited one oxidative redox couple around 1.08–1.16 V (oxidation onset potential) versus Ag/AgCl in an acetonitrile solution and revealed good stability of the electrochromic characteristics, with a color change from colorless to green at applied potentials ranging from 0 to 1.6 V. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6094–6102, 2006     

Novel thermally stable triarylamine‐containing aromatic polyamides bearing anthrylamine chromophores for highly efficient green‐light‐emitting materials

A series of novel polyamides with pendent anthrylamine units were prepared via the direct phosphorylation polycondensation from various diamines and the anthrylamine‐based aromatic dicarboxylic acid, 9‐[N,N‐di(4‐carboxyphenyl)amino]anthracene (4). The aromatic polyamides had useful levels of thermal stability associated with relatively high softening temperatures (T_s) (290–300 °C), 10% weight‐loss temperatures (T_d¹⁰) nearly in excess of 550 °C, and char yields at 800 °C in nitrogen higher than 60%. These aromatic polyamides I exhibited highly photoluminescence quantum yield in NMP solution ranges from 55% for Ia to 74% for Ie due to the introduction of anthrylamine chromophores. Cyclic voltammograms of the polyamide films cast onto an indium‐tin oxide (ITO)‐coated glass substrate exhibited one oxidation and reduction couples (E_onset) around 1.10 and ?1.50 V versus Ag/AgCl in acetonitrile (CH₃CN) and DMF solutions, respectively. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7354–7368, 2008     

Synthesis and properties of wholly aromatic polymers bearing cardo fluorene moieties

Three series of aromatic polyamides, polyesters, and poly(1,3,4‐oxadiazole)s containing bulky fluorene structures were prepared from 9,9‐bis(4‐carboxyphenyl) fluorene. All of the polymers were readily soluble in many organic solvents and showed useful thermal stability associated with high glass‐transition temperatures in the range of 220–366 °C. These wholly aromatic polymer films were colorless, with high optical transparency, and exhibited UV‐vis absorption bands at 266–348 nm and photoluminescence maximum bands at 368–457 nm within the purple to green region in N,N‐dimethylacetamide (DMAc) solutions. The poly(amine‐amide) Ic exhibited excellent electrochromic contrast and coloration efficiency, changing color from the colorless neutral form to green and then to the dark blue oxidized forms with good stability of electrochromic characteristics. Almost all of these wholly aromatic polymer films were colorless and showed high optical transparency. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4352–4363, 2007     

Fluorescent and electrochromic aromatic polyamides with 4‐tert‐butyltriphenylamine chromophore

A new triphenylamine‐based aromatic dicarboxylic acid monomer, 4‐tert‐butyl‐4′,4″‐dicarboxytriphenylamine ( 2 ), was synthesized from the cesium fluoride mediated N,N‐diarylation reaction of 4‐tert‐butylaniline with 4‐fluorobenzonitrile and subsequent alkaline hydrolysis of the dinitrile intermediate. A series of six aromatic polyamides 4a‐4f with tert‐butyltriphenylamine groups was prepared from the newly synthesized dicarboxylic acid and various aromatic diamines. These polyamides were readily soluble in many organic solvents and could be solution‐cast into flexible and strong films. The glass‐transition temperatures of these polymers were in the range of 274–311 °C. These polymers exhibited strong UV‐vis absorption bands at 356–366 nm in NMP solution. Their photoluminescence spectra showed maximum bands around 433–466 nm in the blue region. Cyclic voltammograms of all the polyamides exhibited reversible oxidation redox couples in acetonitrile. The polyamide 4f, with tert‐butyltriphenylamine segment in both diacid and diamine residues, exhibited stable electrochromic characteristics with a color change from a colorless neutral form, through a green semioxidized form, to a deep purple fully oxidized form. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2798–2809, 2010     

Thermally stable,light‐emitting,triphenylamine‐containing poly(amine hydrazide)s and poly(amine‐1,3,4‐oxadiazole)s bearing pendent carbazolyl groups

A series of new organosoluble poly(amine hydrazide)s were synthesized via the Yamazaki phosphorylation reaction and were solution‐cast into transparent films. Differential scanning calorimetry indicated that the hydrazide polymers could be thermally cyclodehydrated into the corresponding oxadiazole polymers in the range of 300–400 °C. The resulting poly(amine‐1,3,4‐oxadiazole)s exhibited glass‐transition temperatures in the range of 276–297 °C, 10% weight loss temperatures in excess of 520 °C, and char yields at 800 °C in nitrogen higher than 67%. The hole‐transporting and electrochromic properties were examined with electrochemical and spectroelectrochemical methods. Cyclic voltammograms of these polymers prepared by the casting of polymer solutions onto an indium tin oxide coated glass substrate exhibited two reversible oxidative redox couples at 1.10–1.19 and 1.35–1.60 V versus Ag/AgCl in an acetonitrile solution, respectively. The poly(amine hydrazide)s revealed excellent stability of the electrochromic characteristics, changing color from the original pale yellow to green and then to blue. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 48–58, 2007     

High Tg,ambipolar, and near‐infrared electrochromic anthraquinone‐based aramids with intervalence charge‐transfer behavior

Two novel series of ambipolar and near‐infrared electrochromic aromatic polyamides with electroactive anthraquinone group were synthesized from new aromatic diamines, 2‐(bis(4‐aminophenyl)amino)anthracene‐9,10‐dione and 2‐(4‐(bis(4‐aminophenyl)amino)phenoxy)anthracene‐9,10‐dione, respectively, via low‐temperature solution polycondensation reaction. These polymers were readily soluble in many polar solvents and showed useful levels of thermal stability associated with high glass‐transition temperatures (T_g) (285–360 °C). Electrochemical studies of these electrochromic polyamides revealed ambipolar behavior with reversible redox couples and high contrast ratio both in the visible range and near‐infrared region. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Synthesis and properties of new aromatic polyamides with redox‐active 2,4‐dimethoxytriphenylamine moieties

A new triphenylamine‐based diamine monomer, 4,4′‐diamino‐2″,4″‐dimethoxytriphenylamine ( 2 ), was synthesized from readily available reagents and was reacted with various aromatic dicarboxylic acids to produce a series of aromatic polyamides ( 4a–h ) containing the redox‐active 2,4‐dimethoxy‐substituted triphenylamine (dimethoxyTPA) unit. All the resulting polyamides were readily soluble in polar organic solvents and could be solution cast into tough and flexible films. These polymers exhibited good thermal stability with glass transition temperatures of 243–289 °C and softening temperatures of 238–280 °C, 10% weight loss temperatures in excess of 470 °C in nitrogen, and char yields higher than 60% at 800 °C in nitrogen. The redox behaviors of the polymers were examined using cyclic voltammetry (CV). All these polyamides showed two reversible oxidation processes in the first CV scan. The polymers also displayed low ionization potentials as a result of their dimethoxyTPA moieties. In addition, the polymers displayed excellent stability of electrochromic characteristics with coloration change from a colorless neutral state to green and blue‐purple oxidized states. These anodically coloring polyamides showed high green coloration efficiency (CE = 329 cm²/C), high contrast of optical transmittance change (ΔT% = 84% at 829 nm), and long‐term redox reversibility. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3392–3401, 2010     

Synthesis and characterization of a novel electrochromic aromatic polyamide from AB‐type triphenylamine‐based monomer

A new triphenylamine‐based polyamide I was prepared by direct polycondensation of AB‐type monomer, 4‐amino‐4′‐carboxy‐4″‐methoxytriphenylamine ( 4 ), in the presence of triphenyl phosphite and pyridine as condensation agents. The obtained polyamide I showed excellent solubility in aprotic polar solvents such as NMP, DMAc, DMF, and DMSO and could be cast into transparent film with weight‐average molecular weight (M_w = 63,400) and polydispersity index (PDI = 1.79). The polyamide I exhibited good thermal stability with relatively high glass‐transition temperature (282 °C), 10% weight‐loss temperature above 470 °C under a nitrogen atmosphere, and char yield at 800 °C in nitrogen higher than 64%. It also showed maximum ultraviolet‐visible absorption at 362 nm and exhibited fluorescence emission maxima at 493 nm in NMP solution with fluorescence quantum yield 4.4%. Cyclic voltammogram of polyamide I film cast onto an indium tin oxide coated glass substrate exhibited one oxidative redox couple at 0.72 V (oxidation onset potential) versus Ag/AgCl in acetonitrile solution and revealed good stability of the electrochromic characteristic with a color change from colorless to green at applied potentials ranging from 0.00 to 1.10 V. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1988–2001, 2009     

Chemical modification of the pendant structure of wholly aromatic polyamides: Toward functional high‐performance materials with tuned chromogenic and fluorogenic behavior

This work describes the preparation of functional aromatic polyamides with pendant fluorescent chemical structures. The preparation of a parent copolyamide with a lateral fluorene moiety anchored to the main chain through a urea group is described, along with the chemical modification of the fluorene moieties to render six copolymers with different fluorescent behaviors. The easy and clean chemical modification of the polyamide structure permits the preparation of high‐performance materials with “a la carte” fluorescence properties. The characteristics of these materials make them useful for cutting‐edge technologies associated with the fluorescence of the pendant fluorene moiety and with the host behavior of the urea motif, that is, fluorescent sensing of analytes or hybrid luminescent converter—light‐emitting diode systems. The chemical modification of the polymer structure was carried out with chemicals and conditions optimized for polyamide models. The influence of the chemical structure of the pendant fluorene core has also been addressed in terms of thermal properties, solubility, water uptake, and so forth. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3823–3833, 2010     

Pyrenylamine‐functionalized aromatic polyamides as efficient blue‐emitters and multicolored electrochromic materials

A series of novel aromatic polyamides with pyrenylamine in the backbone were prepared from a newly synthesized dicarboxylic acid monomer, N,N‐di(4‐carboxyphenyl)‐1‐aminopyrene, and various aromatic diamines via the phosphorylation polyamidation technique. These polyamides were readily soluble in many organic solvents and could be solution‐cast into tough and amorphous films. They had useful levels of thermal stability with glass‐transition temperatures in the range of 276–342 °C and 10% weight loss temperatures in excess of 500 °C. The dilute N‐methyl‐2‐pyrrolidone (NMP) solutions of these polymers exhibited fluorescence maxima around 455–540 nm with quantum yields up to 56.9%. The polyamides also showed remarkable solvatochromism of the emission spectra. Their films showed reversible electrochemical oxidation and reduction accompanied by strong color changes from colorless neutral state to purple oxidized state and to yellow reduced state. The polyamide 4g containing the pyrenylamine units in both diacid and diamine sides exhibited easily accessible p‐ and n‐doped states, together with multicolored electrochromic behaviors. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Synthesis and characterization of wholly aromatic poly(azomethine)s containing donor–acceptor triphenylamine moieties

N‐(4‐nitrophenyl)‐4′,4″‐bisformyl‐diphenylamine was synthesized from N‐(4‐nitrophenyl)‐diphenylamine by the Vilsmeier‐Haack reaction. Soluble aromatic poly(azomethine)s (PAMs) were prepared by the solution polycondensation of N‐(4‐nitrophenyl)‐4′,4″‐bisformyl‐diphenylamine and aromatic diamine in N‐methyl‐2‐pyrrolidone (NMP) at room temperature under reduced pressure. All the PAMs are highly soluble in various organic solvents, such as N,N‐dimethylacetamide (DMAc), chloroform (CHCl₃), and tetrahydrofuran (THF). Differential scanning calorimetry (DSC) indicated that these PAMs had glass‐transition temperatures (T_gs) in the range of 170–230 °C, and a 10% weight‐loss temperatures in excess of 490 °C with char yield at 800 °C in nitrogen higher than 60%. These PAMs in NMP solution showed UV‐Vis charge‐transfer (CT) absorption at 405–421 nm and photoluminescence peaks around 462–466 nm with fluorescence quantum efficiency (Φ_F) 0.10–0.99%. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of these PAMs can be determined from cyclic voltammograms as 4.86–5.43 and 3.31–3.34 eV, respectively. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4921–4932, 2007     

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     

Mixed‐valence class I transition and electrochemistry of bis(triphenylamine)‐based aramids containing isolated ether‐linkage

A series of solution‐processable electrochromic (EC) aromatic polyamides with bis(triphenylamine)ether (TPAO) units in the backbone were prepared by the phosphorylation polyamidation from a newly synthesized diamine monomer, bis(N‐4‐aminophenyl‐N‐4‐methoxyphenyl‐4‐aminophenyl)ether, and various dicarboxylic acids. These polymers were highly soluble in many organic solvents and showed useful levels of thermal stability associated with high glass‐transition temperatures and high char yields (higher than 50 at 800 °C in nitrogen). The polymer films showed reversible electrochemical oxidation and electrochromism with high contrast ratio in the visible range, which also exhibited moderate coloration efficiency (CE), low switching time, and good stability. Especially, the polyamides with two electroactive nitrogen centers only showed one‐stage oxidative coloring (no intervalence charge‐transfer [IV‐CT] band was detected), implying the two electrons are simultaneously removed from the TPAO units on account of the ether‐linkage definitely isolated the two redox centers. The mixed‐valence (MV) Class I/II/III transition and electrochemistry of the synthesized model compounds were investigated for the bridged triarylamine system with various N? N distances and intramolecular electron transfer (ET) capability. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Novel organosoluble aromatic polyimides bearing pendant methoxy‐substituted triphenylamine moieties: Synthesis,electrochromic, and gas separation properties

Four series of polyimides I – VI with pendent triphenylamine (TPA) units having inherent viscosities of 0.44–0.88 dL/g were prepared from four diamines with two commercially available tetracarboxylic dianhydrides via a conventional two‐step procedure that included a ring‐opening polyaddition to give polyamic acids, followed by chemical cyclodehydration. These polymers were amorphous and could afford flexible films. All the polyimides had useful levels of thermal stability associated with high softening temperatures (279–300 °C), 10% weight‐loss temperatures in excess of 505 °C, and char yields at 800 °C in nitrogen higher than 58%. The hole‐transporting and electrochromic properties were examined by electrochemical and spectroelectrochemical methods. Cyclic voltammograms of the polyimide films cast onto an indium‐tin oxide (ITO)‐coated glass substrate exhibited a or two reversible oxidation couples at 0.65–0.78 and 1.00–1.08 V versus Ag/AgCl in acetonitrile solution. The polymer films revealed electrochromic characteristics with a color change from neutral pale yellowish to blue doped form at applied potentials ranging from 0.00 to 1.20 V. The CO₂ permeability coefficients (P) and permeability selectivity (P/P) for these polyimide membranes were in the range of 4.73–16.82 barrer and 9.49–51.13, respectively. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7937–7949, 2008     

Novel aromatic polyamides containing 2‐diphenylamino‐(9,9‐dimethylamine) units as multicolored electrochromic and high‐contrast electrofluorescent materials

A series of electrochromic and photoluminescence‐active polyamides 4a‐4e were prepared from a novel dicarboxylic acid, N,N‐di(4‐carboxyphenyl)‐2‐amino‐9,9‐dimethylfluorene, and five diamines via a condensation polymerization. These polyamides were amorphous and readily soluble in many solvents. The glass transition temperatures were in the range of 281–339 °C and the 10% weight loss temperatures in nitrogen were in excess of 490 °C. The polyamides exhibited strong fluorescence in either solution or solid states. The polyamides 4a‐4d showed reversible electrochemical redox with color changing from colorless to grey‐green. Specially, the polyamide 4e with 2‐diphenylamino‐(9,9‐dimethylamine) group in both diamine and dicarboxylic acid residues exhibited multicolored electrochromic behaviors. Furthermore, the fluorescence of these polyamides could be reversibly electroswitched with a high contrast up to 221.4, enabling their potential applications in dual‐switching electrochromic/electrofluorescent materials. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 213–222     

Synthesis and photoluminescent and electrochromic properties of aromatic poly(amine amide)s bearing pendent N‐carbazolylphenyl moieties

A series of novel poly(amine amide)s ( IIa – IIl ) with pendent N‐carbazolylphenyl units having inherent viscosities of 0.25–1.06 dL/g were prepared via direct phosphorylation polycondensation from various dicarboxylic acids and a carbazole‐based aromatic diamine. Except for poly(amine amide) IIc , derived from trans‐1,4‐cyclohexanedicarboxylic acid, all the other amorphous poly(amine amide)s were readily soluble in many polar solvents, such as N,N‐dimethylacetamide and N‐methyl‐2‐pyrrolidone (NMP), and could be cast into transparent and flexible films. The aromatic poly (amine amide)s had useful levels of thermal stability associated with relatively high glass‐transition temperatures (268–331 °C), 10% weight loss temperatures in excess of 540 °C, and char yields at 800 °C in nitrogen higher than 60%. These polymers exhibited maximum ultraviolet–visible absorption at 293–361 nm in NMP solutions. Their photoluminescence in NMP solutions exhibited fluorescence emission maxima around 362 and 448–499 nm for aromatic–aliphatic poly(amine amide)s IIa – IIc and aromatic poly (amine amide)s IId – IIl , respectively. The fluorescence quantum yield in NMP solutions ranged from 0.34% for IIj to 4.44% for IIa . The hole‐transporting and electrochromic properties were examined with electrochemical and spectroelectrochemical methods. Cyclic voltammograms of the poly(amine amide) films cast onto an indium tin oxide coated glass substrate exhibited reversible oxidation at 0.81 V and irreversible oxidation redox couples at 1.20 V versus Ag/AgCl in acetonitrile solutions, and they revealed excellent stability of the electrochromic characteristics, with a color change from yellow to green at applied potentials ranging from 0.00 to 1.05 V. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4108–4121, 2006     

Synthesis and characterization of novel soluble triphenylamine‐containing aromatic polyamides based on N,N′‐bis(4‐aminophenyl)‐N,N′‐diphenyl‐1,4‐phenylenediamine

A new triphenylamine‐containing aromatic diamine, N, N′‐bis(4‐aminophenyl)‐N, N′‐diphenyl‐1,4‐phenylenediamine, was prepared by the condensation of N,N′‐diphenyl‐1,4‐phenylenediamine with 4‐fluoronitrobenzene, followed by catalytic reduction. A series of novel aromatic polyamides with triphenylamine units were prepared from the diamine and various aromatic dicarboxylic acids or their diacid chlorides via the direct phosphorylation polycondensation or low‐temperature solution polycondensation. All the polyamides were amorphous and readily soluble in many organic solvents such as N, N‐dimethylacetamide and N‐methyl‐2‐pyrrolidone. These polymers could be solution cast into transparent, tough, and flexible films with good mechanical properties. They had useful levels of thermal stability associated with relatively high glass‐transition temperatures (257–287 °C), 10% weight‐loss temperatures in excess of 550 °C, and char yields at 800 °C in nitrogen higher than 72%. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2810–2818, 2002     

Enhancement of redox stability and electrochromic performance of aromatic polyamides by incorporation of (3,6‐dimethoxycarbazol‐9‐yl)‐triphenylamine units

New series aromatic polyamides with (carbazol‐9‐yl)triphenylamine units were synthesized from a newly synthesized diamine monomer, 4,4′‐diamino‐4″‐(3,6‐dimethoxycarbazol‐9‐yl) triphenylamine, and aromatic dicarboxylic acids via the phosphorylation polyamidation technique. These polyamides exhibit good solubility in many organic solvents and can be solution‐cast into flexible and strong films with high thermal stability. They show well‐defined and reversible redox couples during oxidative scanning, with a strong color change from colorless neutral form to yellowish green and blue oxidized forms at applied potentials scanning from 0.0 to 1.3 V. They show enhanced redox‐stability and electrochromic performance as compared to the corresponding analogs without methoxy substituents on the active sites of the carbazole unit. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 272–286     

High solubility,low‐dielectric constant,and optical transparency of novel polyimides derived from 3,3′,5,5′‐tetramethyl‐4,4′‐diaminodiphenyl‐4″‐isopropyltoluene

A series of novel polyimides (PIs) ( 3a–d ) were prepared from 3,3′,5,5′‐tetramethyl‐4,4′‐diaminodiphenyl‐4 ″ ‐isopropyltoluene ( 1 ) with four aromatic dianhydrides via a one‐step high temperature polycondensation procedure. The obtained PIs showed excellent solubility, with most of them dissoluble at a concentration of 10 wt % in amide polar solvents and chlorinated solvents. Their films were nearly colorless and exhibited high‐optical transparency, with the UV cutoff wavelength in the range of 328–353 nm and the transparency at 450 nm >80%. They also showed low‐dielectric constant (2.49–2.94 at 1 MHz) and low‐water absorptions (0.44–0.65%). Moreover, these PIs possessed high‐glass transition temperatures (T_g) beyond 327 °C and excellent thermal stability with 10% weight loss temperatures in the range of 530–555 °C in nitrogen atmosphere. In comparison with some fluorinated poly(ether imide)s derived from the trifluoromethyl‐substituted bis(ether amine)s, the resultant PIs 3a–d showed better solubility, lower cutoff wavelength, and higher T_g. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3309–3317, 2009     

Synthesis of highly refractive and transparent polyimides derived from 4,4′‐thiobis[2″,6″‐dimethyl‐4″‐(p‐phenylenesulfanyl)aniline]

New sulfur‐containing aromatic diamines with methyl groups at the ortho position of amino groups have been developed to prepare highly refractive and transparent aromatic polyimides (PIs) in the visible region. All aromatic PIs derived from 4,4′‐thiobis[2″‐methyl‐4″‐(p‐phenylenesulfanyl)aniline ( 2 ), 4,4′‐thiobis[2,″6″‐dimethyl‐4″‐(p‐phenylenesulfanyl)aniline ( 5 ), and aromatic dianhydride, 4,4′‐[p‐thiobis(phenylenesulfanyl)]diphthalic anhydride ( 6 ) were prepared via a two‐step polycondensation. All PIs showed good thermal properties, such as 10% weight loss temperature in the range of 497–500 °C and glass transition temperatures above 196 °C. In addition, the PIs showed good optical properties, such as optical transparency above 75% at 450 nm with a 10‐μm film thickness, high refractive indices ranging from 1.7135 to 1.7301, and small in‐plane/out‐of‐plane birefringences between 0.0066 and 0.0076. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 656–662, 2010