Synthesis and properties of new hydroxyl‐pendant aromatic polyimides derived from trimethylsilylated 4,4′‐diamino‐3,3′‐dihydroxybiphenyl and aromatic tetracarboxylic dianhydrides

New phenolic hydroxyl‐pendant aromatic polyimides were synthesized with the N‐silylated diamine method in two steps: the ring‐opening polyaddition of tetrakis(trimethylsilyl)‐substituted 4,4′‐diamino‐3,3′‐dihydroxybiphenyl to various aromatic tetracarboxylic dianhydrides, giving trimethylsiloxy‐pendant poly(amic acid) trimethylsilyl esters, and thermal imidization. The hydroxyl‐bearing polyimides were amorphous but insoluble in organic solvents. They had glass‐transition temperatures greater than 370 °C and temperatures of 10% weight loss greater than 415 °C in nitrogen. The hydroxyl‐pendant polypyromellitimide film had a high tensile strength and a high modulus of 310 MPa and 10 GPa, respectively. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1790–1795, 2002     

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     

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 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     

Synthesis and characterization of soluble polyimides derived from 2,2′‐Bis(3,4‐dicarboxyphenoxy)‐9,9′‐spirobifluorene dianhydride

The synthesis of aromatic poly(ether imide)s containing spirobifluorene units in the polymer backbone is described. 2,2′‐Bis(3,4‐dicarboxyphenoxy)‐9,9′‐spirobifluorene dianhydride, which was used as a new monomer, was synthesized with 2,2′‐dihydroxy‐9,9′‐spirobifluorene as the starting material. In the spiro‐segment, the rings of the connected bifluorene were orthogonally arranged. This bis(ether anhydride) monomer was employed in reactions with a variety of aromatic diamines to furnish poly(ether imide)s, involving an initial ring‐opening polycondensation and subsequent chemically induced cyclodehydration. Excellent solubility in common organic solvents at room temperature, good optical transparency, and high thermal stability are the prominent characteristic features of these new polymers, which can be attributed to the presence of spiro‐fused orthogonal bifluorene segments along the polymer chain. The glass‐transition temperatures of the polyimides were 240–293 °C, and the 5% weight‐loss temperatures were greater than 500 °C. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 262–268, 2002     

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 characterization of novel aromatic polyimides from 4,4‐bis(p‐aminophenoxymethyl)‐ 1‐cyclohexene

A novel diamine, 4,4‐bis(p‐aminophenoxymethyl)‐1‐cyclohexene (CHEDA), was synthesized from 4,4‐bis(hydroxymethyl)‐1‐cyclohexene and p‐chloronitrobenzene by nucleophilic aromatic substitution and subsequent catalytic reduction of the intermediate dinitro compound. A series of aromatic polyimides were prepared from CHEDA and commercial dianhydrides with varying flexibility and electronic character in two‐step direct polycondensation reactions. High molecular weight polyimides with intrinsic viscosities between 0.57 and 10.2 dL/g were obtained. Most of these polyimides, excluding those from PMDA and BPDA, were soluble in polar aprotic solvents such as NMP and DMAc, and many were also soluble in CHCl₃ and THF. DSC analysis revealed glass transitions in the range of 190 to 250°C. No significant weight losses occurred below 450°C in nitrogen and 350°C in air. Bromination and epoxidation of cyclohexene double bond in CHDEA–6FDA (3e) were investigated as examples of possible polymer modifications. Qualitative epoxidation and selective bromination of the double bond were demonstated. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1189–1197, 1999     

Synthesis and properties of new soluble triphenylamine‐based aromatic poly(amine amide)s derived from N,N′‐bis(4‐carboxyphenyl)‐N,N′‐diphenyl‐1,4‐phenylenediamine

A new triphenylamine‐containing aromatic dicarboxylic acid, N,N′‐bis(4‐carboxyphenyl)‐N,N′‐diphenyl‐1,4‐phenylenediamine, was synthesized by the condensation of N,N′‐diphenyl‐1,4‐phenylenediamine with 4‐fluorobenzonitrile, followed by the alkaline hydrolysis of the intermediate dinitrile compound. A series of novel triphenylamine‐based aromatic poly(amine amide)s with inherent viscosities of 0.50–1.02 dL/g were prepared from the diacid and various aromatic diamines by direct phosphorylation polycondensation. All the poly(amine amide)s were amorphous in nature, as evidenced by X‐ray diffractograms. Most of the poly(amine amide)s were quite soluble in a variety of organic solvents and could be solution‐cast into transparent, tough, and flexible films with good mechanical properties. They had useful levels of thermal stability associated with glass‐transition temperatures up to 280 °C, 10% weight‐loss temperatures in excess of 575 °C, and char yields at 800 °C in nitrogen higher than 60%. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 94–105, 2003     

Synthesis and properties of polyimides derived from 9,10‐dialkyloxy‐1,2,3,4,5,6,7,8‐octahydro‐2,3,6,7‐anthracenetetracarboxylic 2,3:6,7‐dianhydrides

A series of new polyimides containing alicyclic units and alkyloxy side chains were prepared from 9,10‐dialkyloxy‐1,2,3,4,5,6,7,8‐octahydro‐2,3,6,7‐anthracenetetracarboxylic 2,3:6,7‐dianhydrides and various aromatic diamines. Their physical properties and structures were investigated. Polymers were obtained with inherent viscosities of 0.24–0.53 dL/g. In comparison with the aromatic polyimides, most polymers were readily soluble in common organic solvent such as N‐methylpyrrolidone and m‐cresol. These polymers had glass‐transition temperatures between 111 and 296 °C depending on the structure of the repeating unit and 10% weight‐loss temperatures of 418–477 °C in nitrogen. Wide‐angle X‐ray diffractometry for as‐polymerized samples revealed very low crystallinity and layered structures, which were better developed in the polymers with longer side chains. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1764–1774, 2002     

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     

Synthesis and properties of soluble and light‐colored poly(amide‐imide‐imide)s on the basis of tetraimide‐dicarboxylic acid condensed from 4,4′‐oxydiphthalic anhydride, 2,2‐bis[4‐(4‐aminophenoxy)phenyl]propane,and m‐aminobenzoic acid,and various aromatic diamines

A new type of tetraimide‐dicarboxylic acid ( I ) was synthesized starting from the ring‐opening addition of m‐aminobenzoic acid, 4,4′‐oxydiphthalic anhydride, and 2,2‐bis[4‐(4‐aminophenoxy)phenyl]propane at a 2:2:1 molar ratio in N‐methyl‐2‐pyrrolidone (NMP), followed by cyclodehydration to the diacid I . A series of soluble and light‐colored poly(amide‐imide‐imide)s ( III _a–j) was prepared by triphenyl phosphite‐activated polycondensation from I with various aromatic diamines ( II _a–j). All films cast from N,N‐dimethylacetamide (DMAc) had cutoff wavelengths shorter than 390 nm (374–390 nm) and b* values between 25.26 and 43.61; these polymers were much lighter in color than the alternating trimellitimide series. All of the polymers were readily soluble in a variety of organic solvents such as NMP, DMAc, N,N‐dimethylformamide, dimethyl sulfoxide, and even in less polar m‐cresol and pyridine. Polymers III _a–j afforded tough, transparent, and flexible films that had tensile strengths ranging from 96 to 118 MPa, elongations at break from 9 to 11%, and initial moduli from 2.0 to 2.5 GPa. The glass‐transition temperatures of the polymers were recorded at 240–268 °C. They had 10% weight loss at a temperature above 540 °C and left more than 55% residue even at 800 °C in nitrogen. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 707–718, 2002; DOI 10.1002/pola.10153     

Anionic polymerization of N,N‐dialkyl‐2‐methylenebut‐3‐enamide: Effect of alkyl substituents on polymerization behavior

Anionic polymerizations of three 1,3‐butadiene derivatives containing different N,N‐dialkyl amide functions, N,N‐diisopropylamide (DiPA), piperidineamide (PiA), and cis‐2,6‐dimethylpiperidineamide (DMPA) were performed under various conditions, and their polymerization behavior was compared with that of N,N‐diethylamide analogue (DEA), which was previously reported. When polymerization of DiPA was performed at ?78 °C with potassium counter ion, only trace amounts of oligomers were formed, whereas polymers with a narrow molecular weight distribution were obtained in moderate yield when DiPA was polymerized at 0 °C in the presence of LiCl. Decrease in molecular weight and broadening of molecular weight distribution were observed when polymerization was performed at a higher temperature of 20 °C, presumably because of the effect of ceiling temperature. In the case of DMPA, no polymer was formed at 0 °C and polymers with relatively broad molecular weight distributions (M_w/M_n = 1.2) were obtained at 20 °C. The polymerization rate of PiA was much faster than that of the other monomers, and poly(PiA) was obtained in high yield even at ?78 °C in 24 h. The microstructure of the resulting polymers were exclusively 1,4‐ for poly(DMPA), whereas 20–30% of the 1,2‐structure was contained in poly(DiPA) and poly(PiA). © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3714–3721, 2010     

Ring‐opening copolymerization of ethylene carbonate and ε‐caprolactone catalyzed by neodymium tris(2,6‐di‐tert‐butyl‐4‐methylphenolate): Synthesis,characterization, and dynamic mechanic analysis

The ring‐opening copolymerization of ethylene carbonate (EC) with ε‐caprolactone (CL) was carried out using neodymium tris(2,6‐di‐tert‐butyl‐4‐methylphenolate) as a single‐component catalyst. Copolymers containing up to 22.0% EC contents with high molecular weights (up to 23.97 × 10⁴) and moderate molecular weight distributions (between 1.66 and 2.03) were synthesized at room temperature. Compared with homopoly(ε‐caprolactone), the copolymers with EC units exhibited increased glass transition temperatures (?35.6 °C), reduced melting temperatures (44.5 °C), and greatly enhanced elongation percentage at break (2383%) based on dynamic mechanic analysis. The crystallinities of the copolymers decreased with the increasing EC molar percentage in the products. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4050–4055, 2008     

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     

Electrical and self‐heating properties of UHMWPE‐EMMA‐NiCF composite films

Conductive polymer composites (CPC) containing nickel‐coated carbon fiber (NiCF) as filler were prepared using ultra‐high molecular weight polyethylene (UHMWPE) or its mixture with ethylene‐methyl methacrylate (EMMA) as matrix by gelation/crystallization from dilute solution. The electrical conductivity, its temperature dependence, and self‐heating properties of the CPC films were investigated as a function of NiCF content and composition of matrix in details. This article reported the first successful result for getting a good positive temperature coefficient (PTC) effect with 9–10 orders of magnitude of PTC intensity for UHMWPE filled with NiCF fillers where the pure UHMWPE was used as matrix. At the same time, it was found that the drastic increase of resistivity occurred in temperature range of 120–200 °C, especially in the range of 180–200 °C, for the specimens with matrix ratio of UHMWPE and EMMA (UHMWPE/EMMA) of 1/0 and 1/1 (NiCF = 10 vol %). The SEM observation revealed to the difference between the surfaces of NiCF heated at 180 and 200 °C. Researches on the self‐heating properties of the composites indicated a very high heat transfer for this kind of CPCs. For the 1/1 composite film with 10 vol % NiCF, surface temperature (T_s) reached 125 °C within 40 s under direct electric field where the supplied voltage was only 2 V corresponding to the supplied power as 0.9 W. When the supplied voltage was enough high to make T_s beyond the melting point of UHMWPE component, the T_s and its stability of CPC films were greatly influenced by the PTC effect. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1253–1266, 2009     

Preparation and physical properties of poly(4,4′‐diamino‐3′‐carbamoylbenzanilide terephthalamide) and poly(4,4′‐diamino‐3′‐carbamoylbenzanilide isophthalamide) films

To prepare thermally stable and high‐performance polymeric films, new solvent‐soluble aromatic polyamides with a carbamoyl pendant group, namely poly(4,4′‐diamino‐3′‐carbamoylbenzanilide terephthalamide) (p‐PDCBTA) and poly(4,4′‐diamino‐3′‐carbamoylbenzanilide isophthalamide) (m‐PDCBTA), were synthesized. The polymers were cyclized at around 200 to 350 °C to form quinazolone and benzoxazinone units along the polymer backbone. The decomposition onset temperatures of the cyclized m‐ and p‐PDCBTAs were 457 and 524 °C, respectively, lower than that of poly(p‐phenylene terephthalamide) (566 °C). For the p‐PDCBTA film drawn by 40% and heat‐treated, the tensile strength and Young's modulus were 421 MPa and 16.4 GPa, respectively. The film cyclized at 350 °C showed a storage modulus (E′) of 1 × 10¹¹ dyne/cm² (10 GPa) over the temperature range of room temperature to 400 °C. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 775–780, 2000     

Synthesis and properties of organosoluble polynaphthalimides based on 1,4,5,8‐naphthalene tetracarboxylic dianhydride, 3,3‐bis[4‐(4‐aminophenoxy)phenyl]phthalide,and various aromatic diamines

Two series of polynaphthalimides (PNIs), II and III , were prepared from 1,4,5,8‐naphthalene tetracarboxylic dianhydride with the usual aromatic diamines ( Ia – Ih ) or Ia , which was used as a soluble modifying agent, and Ib – Ih via a one‐stage process with high‐temperature condensation. Series II and III had inherent viscosities of 0.57–1.34 and 1.15–1.63 dL/g, respectively. IIa and most of the III series were soluble in 1‐methy‐2‐pyrrolidone and m‐cresol at 5–10 wt % and afforded transparent and tough films by m‐cresol solvent casting with a tensile strength in the range of 75–99 MPa. The glass‐transition temperature and softening temperature of these PNIs were in the ranges of 360–404 and 188–241 °C, respectively, and the 10% weight loss temperatures were above 495 °C, with more than a 44% char yield at 800 °C in nitrogen. These PNI films had dielectric constants of 4.14–6.46 (1 MHz), with moisture absorption in the range of 0.87–1.91 wt %. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 940–948, 2006     

Soluble fluorinated polyimides derived from 1,4‐ (4′‐aminophenoxy)‐2‐(3′‐trifluoromethylphenyl)benzene and aromatic dianhydrides

New fluorinated aromatic polyimides were prepared from 1,4‐(4′‐aminophenoxy)‐2‐(3′‐trifluoromethylphenyl)benzene and aromatic dianhydrides via the polycondensation of one‐step high‐temperature and two‐step thermal or chemical imidization methods. Experimental results indicated that some of the polyimides were soluble both in strong dipolar solvents (N‐methyl‐2‐pyrrolidone or N,N‐dimethylacetamide) and in common organic solvents such as tetrahydrofuran, CHCl₃, and acetone. The polyimides showed exceptional thermal and thermooxidative stability and good mechanical properties. No weight loss was detected before a temperature of 520 °C in nitrogen, and the glass‐transition temperatures ranged from 208 to 251 °C. Low dielectric constants (2.55–2.71 at 1 MHz), low refractive indices, and low water absorption were also observed. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2404–2413, 2001     

Acid chloride‐functionalized hyperbranched polyester for facile and quantitative chain‐end modification: One‐pot synthesis and structure characterization

Carboxylic acid chloride end‐functionalized all‐aromatic hyperbranched polyesters were prepared from the bulk polycondensation of the AB₂ monomer 5‐(trimethylsiloxy)isophthaloyl dichloride. The acid chloride end functionality of the hyperbranched polyester was modified in situ with methanol and yielded methyl ester ends in a one‐pot process. Chain‐end functionalization and esterification were quantitative according to both potentiometric titration and ¹H NMR analysis. The signals of ¹H and ¹³C NMR spectra of the esterified hyperbranched polyester were fully assigned from model compounds of the focal, linear, dendritic, and terminal units. The degree of branching and molecular weight averages measured by ¹H and ¹³C NMR spectroscopy and multidetector size exclusion chromatography increased systematically with increasing polymerization temperatures between 80 and 200 °C. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2855–2867, 2002     

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