Synthesis and properties of a high‐performance pyrimidine‐containing self‐catalyzed phthalonitrile polymer

A self‐catalytic monomer of phthalonitrile, 2‐amino‐4,6‐bis[3‐(3,4‐dicyano‐phenoxy)phenoxy] pyrimidine (ACPP), was synthesized by a one‐pot method with resorcinol, 2‐amino‐4,6‐dichloropyrimidine, and 4‐nitrophthalonitrile. The chemical structure of the ACPP monomer was characterized by Fourier transform Infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy. The curing behavior of ACPP monomer was studied by differential scanning calorimetric, which indicated that the ACPP monomer had a low melting point (84 °C) and revealed an autocatalytic reaction and tremendously wide processing window (193 °C). Wide‐angle X‐ray diffraction (WAXD) and FTIR analyses were employed to explore the microstructure of the ACPP polymers. The properties of the three polymers with different curing procedures were investigated, which implied that the ACPP polymers exhibited excellent thermal stability, high modulus, superior glass‐transition temperature (T_g > 400 °C), and low water absorption with the increase in curing extent. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2287–2294     

Sustainable,fire‐resistant phthalonitrile‐based glass fiber composites

The sustainable resveratrol‐based phthalonitrile was used in the preparation of E‐glass fiber‐reinforced phthalonitrile composite panels fabricated by hot pressed prepreg consolidation with bis[4‐(3‐aminophenoxy)phenyl]sulfone (m‐BAPS) as the curing additive. This amorphous monomer exhibited excellent viscosities at temperatures below 200 °C, which is applicable to standard processing conditions. Rheometric measurements were used to evaluate the cure of the composite as a function of the postcure conditions. The composite retains >95% of its room temperature storage modulus up to 450 °C based on these postcuring parameters. More importantly, flammability performance of the composite—which was determined in terms of ignitability, heat release, and mass loss rate—excels over other state‐of‐the‐art polymer/glass composites. Even under the most extreme heat fluxes (e.g., 100 kW⋅m⁻²), the composite performs exceptionally well suggesting that resveratrol‐based phthalonitrile composites can be used in fire‐resistant applications. Published 2018.^† J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 1128–1132     

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     

Synthesis and characterization of new polybenzimidazopyrrolones derived from pyridine‐bridged aromatic tetraamines and dianhydrides

A series of new polybenzimidazopyrrolones (polypyrrolone, PPy) were synthesized by polycondensation of pyridine‐bridged aromatic tetraamines, including 2,6‐bis (3′,4′‐diaminophenyl)‐4‐phenylpyridine and 2,6‐bis(3′,4′‐ diaminophenyl)‐4‐(3″‐trifluoromethyl)phenyl pyridine, with various aromatic dianhydrides. Experimental results indicated that the PPys, multiaromatic conjugated and semiladder polymers, showed good thermal stabilities with thermal‐decomposition temperatures of about 500 °C and residual weight retention at 750 °C as high as 84%. PPy films could be obtained by casting the precursor solution, poly(amide amino acid) on glass substrate, followed by thermal dehydrating at elevated temperatures. The polymer films exhibited excellent alkaline hydrolysis resistance, which retained their original shapes and toughness after boiling 7 days in 10% sodium hydroxide solution. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1845–1856, 2004     

Solution,thermal and optical properties of novel poly(pyridinium salt)s derived from conjugated pyridine diamines

Several novel poly(pyridinium salt)s with heterocyclic pyridine moieties in their backbones with tosylate and triflimide counterions were prepared by either ring‐transmutation polymerization reaction of phenylated‐bis(pyrylium tosylate) with isomeric pyridine diamines of 4‐phenyl‐2,6‐bis(4‐aminophenyl)pyridine in dimethyl sulfoxide (DMSO) for 48 h at 130–140 °C or by metathesis reaction of the respective tosylate polymers with lithium triflimide in DMSO at about 60 °C. Their chemical structures were characterized by FTIR, ¹H, ¹³C NMR spectroscopy, and elemental analysis. Their number‐average molecular weights (M_n) were in the range of 8,000–51,000 and their polydispersities in the range of 1.18–2.13 as determined by gel permeation chromatography. They had excellent thermal stabilities of 340–458 °C and high glass transition temperatures >200 °C. As they showed good solubilities in common organic solvents, their solution properties were also characterized for their lyotropic liquid‐crystalline properties with polarizing optical microscopy (POM) studies. Their photoluminescent properties were examined by using a spectrofluorometer in both solution and solid states. Their quantum yields were rather low, which were in the range of 1.3–2.0%. Additionally, hand‐drawn fibers from the melts were examined to determine their morphologies with a number of microscopic techniques including POM, scanning electron microscopy, and transmission electron microscopy. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Improved synthesis of oligomeric phthalonitriles and studies designed for low temperature cure

An improved synthetic method has been developed for oligomeric aromatic ether ketone‐based phthalonitrile (PN) resins. A new curing additive was studied that lowers the cure temperature of the PN resin to around 150 °C and compared to the traditional high‐temperature aromatic diamine. Mechanical and thermo‐oxidative analyses of polymeric samples from both systems were determined and compared under various curing conditions. The PN polymer exhibited low water absorption regardless of the chosen cure system. Published 2014. This article is a U.S. Government work and is in the public domain in the USA. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1662–1668     

Crystal Structure, Thermal Stability and Luminescence of Coordination Polymer [Cd（BBP）（p-PDOA）]n

Hydrothermal reaction of Cd（NO3）2·4H2O with bbp and p-PDOAH2 at 140 ℃ yielded a novel 1D cadmium（Ⅱ） coordination polymer, [Cd（bbp）（p-PDOA）]n （bbp=2,6-bis（benzimidazol-2-yl）pyridine, p-PDOA=p-phenylenedioxydiacetate dianion）, in which CdN3O4 pentagonal bipyramids were linked by p-PDOA ligands in a bis-bidentate mode to construct a zigzag chain with the adjacent Cd…Cd distance of 1.14（1） nm, There exists a 2D supramolecular network linked by π-π stacking with a face-to-face distance of 0.35（1） nm between the 2,6-bis（benzimidazol-2-yl） pyridine ligands and hydrogen-bonding interactions （0.27（4） nm）. A 3D supramolecular network was further constructed by these non-covalent interactions between the zippers. The TG/DTG showed that its chain skeleton was thermally stable up to 389 ℃ and the blue fluorescent emission of the complex was determined at 428 nm in a solid state with its long decay lifetime of 7.24 ns.     

Synthesis and properties of a bisphenol A based phthalonitrile resin

A multiple aromatic ether linked phthalonitrile was synthesized and characterized. The oligomeric phthalonitrile monomer was prepared from the reaction of an excess amount of bisphenol A with 4,4′‐difluorobenzophenone in the presence of K₂CO₃ as the base in an N,N‐dimethylformamide/toluene solvent mixture, followed by end capping with 4‐nitrophthalonitrile in a two‐step, one‐pot reaction. The monomer properties were compared to those of the known resin 2,2‐bis[4‐(3,4‐dicyanophenoxy)phenyl]propane after being cured in the presence of bis[4‐(4‐aminophenoxy)phenyl]sulfone. Rheometric measurements and thermogravimetric analysis showed that the oligomeric phthalonitrile resin maintained good structural integrity upon heating to elevated temperatures and exhibited excellent thermal properties along with long‐term oxidative stability. The ether‐linked phthalonitrile resin absorbed less than 2.5% water by weight after exposure to an aqueous environment for extended periods. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4136–4143, 2005     

Synthesis and characterization of novel hyperbranched polybenzimidazoles based on an AB2 monomer containing four amino groups and one carboxylic group

A new kind of AB₂ monomer, 4‐[2,6‐bis(3,4‐diaminophenyl)pyridin‐4‐yl]benzoic acid, was synthesized, and several hyperbranched polybenzimidazoles (HPBIs) were prepared through self‐polymerization followed by modification reactions with end‐capping reagents such as 4‐methyl benzoic acid and 3‐[3,5‐bis(trifluoromethyl)phenoxy] benzoic acid. The HPBIs had good solubility in strongly aprotic solvents, such as N‐methyl‐2‐pyrrolidone, N,N′‐dimethylformamide, N,N′‐dimethylacetamide, and dimethyl sulfoxide. They also exhibited excellent thermal properties, with glass‐transition temperatures of 318–381 °C and 10% weight loss in the range of 338–674 °C in nitrogen and 329–509 °C in air. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5729–5739, 2006     

Mitigating chain‐transfer and enhancing the thermal stability of co‐based olefin polymerization catalysts through sterically demanding ligands

Sterically demanding Fe‐ and Co‐based olefin polymerization catalysts 2‐Fe and 2‐Co bearing 2,6‐bis(biphenylmethyl)‐4‐methylaniline substituted bis(imino)pyridine ligands were synthesized and evaluated for ethylene polymerization. The late‐transition metal complexes were characterized by X‐ray diffraction, NMR spectroscopy, and HRMS, while their resultant polymers were characterized by size‐exclusion chromatography and ¹H NMR spectroscopy. While catalyst 2‐Fe was inactive, catalyst 2‐Co was found to polymerize ethylene and avoid any detectable chain‐transfer to aluminum events that are known to plague other Fe‐ and Co‐based catalyst systems and to limit molecular weight. Furthermore, 2‐Co displays virtually perfect thermal stability up to 80 °C and shows greatly enhanced thermal stability at 90 °C as compared to previously reported analogues. These observations are attributed to the extreme steric demand imposed by the ligand which mitigates catalyst transfer, deactivation, and decomposition reactions. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3990–3995     

Synthesis of photosensitive and thermosetting poly(phenylene ether) based on poly[2,6‐di(3‐methyl‐2‐butenyl)phenol‐co‐2,6‐dimethyl‐phenol] and a photoacid generator

A chemically amplified photosensitive and thermosetting polymer based on poly[2,6‐di(3‐methyl‐2‐butenyl)phenol (15 mol %)‐co‐2,6‐dimethylphenol (85 mol %)] ( 3c ) and a photoacid generator [(5‐propylsulfonyloxyimino‐5H‐thiophen‐2‐ylidene)‐(2‐methylphenyl)acetonitrile] was developed. Poly[2,6‐bis(3‐methyl‐2‐butenyl)phenol]‐co‐2,6‐dimethylphenol)] ( 3 ) with high molecular weights (number‐average molecular weight ～ 24,000) was prepared by the oxidative coupling copolymerization of 2,6‐di(3‐methyl‐2‐butenyl)phenol with 2,6‐dimethylphenol in the presence of copper(I) chloride and pyridine as the catalyst under a stream of oxygen. The structures of 3 were characterized with IR, ¹H NMR, and ¹³C NMR spectroscopy. 3 was crosslinked by a thermal treatment at 300 °C for 1 h under N₂. The 5% weight loss temperatures and glass‐transition temperatures of the cured copolymers reached around 420 °C in nitrogen and 300 °C, respectively. The average refractive index of the cured copolymer ( 3c ) film was 1.5452, from which the dielectric constant at 1 MHz was estimated to be 2.6. The resist showed a sensitivity of 35 mJ cm^?2 and a contrast of 1.6 when it was exposed to 436‐nm light, postexposure‐baked at 145 °C for 5 min, and developed with toluene at 25 °C. A fine negative image featuring 8‐μm line‐and‐space patterns was obtained on a film exposed to 100 mJ cm^?2 with 436‐nm light in the contact‐printed mode. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 149–156, 2005     

Synthesis and characterization of new soluble cardo polyamides containing the tricyclo[5.2.1.02,6]decane group

A new cardo dicarboxylic acid, 8,8‐bis[4‐(4‐carboxyphenoxy)phenyl]tricyclo[5.2.1.0^2,6]decane (BCPTD), was synthesized from 4,4′‐(octahydro‐4,7‐methano‐5H‐inden‐5‐ylidene)bisphenol and p‐fluorobenzonitrile via aromatic nucleophilic substitution followed by hydrolysis. A series of new cardo polyamides was prepared by the direct polycondensation of BCPTD and various aromatic diamines in N‐methyl‐2‐pyrrolidinone (NMP) with triphenyl phosphite and pyridine as the condensing agents. Polymers were produced with moderate to high inherent viscosities of 0.65 to 1.08 dL g⁻¹. The polymers, except for polymer PA1 , exhibited number‐average molecular weights and weight‐average molecular weights in the range of 38,400 to 86,300 and 57,800 to 148,000, respectively. Nearly all of the polymers were readily soluble in polar solvents such as NMP, N,N‐dimethylacetamide, N,N‐dimethylformamide, and dimethyl sulfoxide as well as in less polar solvents such as pyridine, γ‐butyrolactone, and tetrahydrofuran. All of the polymers were amorphous, and the polyamide films had a tensile‐strength range of 75 to 128 MPa and a tensile‐modulus range of 2.0 to 2.8 GPa. These polyamides had glass‐transition temperatures between 240 and 269°C and 10% weight‐loss temperatures in the range of 477 to 508°C and 471 to 518°C in nitrogen and air atmospheres, respectively. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 74–79, 2000     

Negative‐type photosensitive poly(phenylene ether) based on poly(2,6‐dimethyl‐1,4‐phenylene ether), a crosslinker,and a photoacid generator

A negative‐type photosensitive poly(phenylene ether) (PSPPE) based on poly(2,6‐dimethyl‐1,4‐phenylene ether) (PPE), a novel crosslinker 4,4′‐methylene‐bis [2,6‐bis(methoxymethyl)phenol] (MBMP) having good compatibility with PPE, and diphenylidonium 9,10‐dimethoxy anthracene‐2‐sulfonate (DIAS) as a photoacid generator (PAG) has been developed. This resist consisting of PPE (73 wt %), MBMP (20 wt %) and DIAS (7 wt %) showed a high sensitivity (D_0.5) of 58 mJ/cm² and a contrast (γ_0.5) of 9.5 when it was exposed to i‐line (365 nm wavelength light), postexposure baked at 145 °C for 10 min, and developed with toluene at 25 °C. A fine negative image featuring 6 μm line‐and‐space pattern was obtained on the film exposed to 300 mJ/cm² of i‐line by a contact‐printed mode. The resulting polymer film cured at 300 °C for 1 h under nitrogen had a low dielectric constant (ε = 2.46) comparable to that of PPE and a higher T_g than that of PPE. In addition, the cured PSPPE film was pretty low water absorption (<0.05%) as same as PPE. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4949–4958, 2008     

Synthesis and characterization of new highly organosoluble poly(etherimide)s derived from 1,1‐bis{4‐[4‐(3,4‐dicarboxyphenoxy)phenyl]‐4‐phenylcyclohexane} dianhydride

A new bulky pendent bis(ether anhydride), 1,1‐bis[4‐(4‐dicarboxyphenoxy)phenyl]‐4‐phenylcyclohexane dianhydride, was prepared in three steps, starting from the nitrodisplacement of 1,1‐bis(4‐hydroxyphenyl)‐4‐phenylcyclohexane with 4‐nitrophthalonitrile to form bis(ether dinitrile), followed by alkaline hydrolysis of the bis(ether dinitrile) and subsequent dehydration of the resulting bis(ether diacid). A series of new poly(ether imide)s were prepared from the bis(ether anhydride) with various diamines by a conventional two‐stage synthesis including polyaddition and subsequent chemical cyclodehydration. The resulting poly(ether imide)s had inherent viscosities of 0.50–0.73 dL g^?1. The gel permeation chromatography measurements revealed that the polymers had number‐average and weight‐average molecular weights of up to 57,000 and 130,000, respectively. All the polymers showed typical amorphous diffraction patterns. All of the poly(ether imide)s showed excellent solubility in comparison with the other polyimides derived from adamantane, norbornane, cyclododecane, and methanohexahydroindane and were readily dissolved in various solvents such as N‐methyl‐2‐pyrrolidinone, N,N‐dimethylacetamide (DMAc), N,N‐dimethylformamide, pyridine, cyclohexanone, tetrahydrofuran, and even chloroform. These polymers had glass‐transition temperatures of 226–255 °C. Most of the polymers could be dissolved in chloroform in as high as a 30 wt % concentration. Thermogravimetric analysis showed that all polymers were stable up to 450 °C, with 10% weight losses recorded from 458 to 497 °C in nitrogen. These transparent, tough, and flexible polymer films could be obtained by solution casting from DMAc solutions. These polymer films had tensile strengths of 79–103 MPa and tensile moduli of 1.5–2.1 GPa. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2066–2074, 2002     

Synthesis and properties of a novel,liquid, trifunctional,cycloaliphatic epoxide

A novel cycloaliphatic triepoxide, 1,1‐bis(2′,3′‐epoxycyclohexyloxymethyl)‐3,4‐epoxycyclohexane ( II ), and its precursor, 1,1‐bis(2′‐cyclohexenyloxymethyl)‐3‐cyclohexene, were synthesized. Their chemical structures were confirmed with IR spectroscopy, elemental analysis, and ¹H NMR spectroscopy. II was easily cured with hexahydro‐4‐methylphthalic anhydride with 1,3,5‐triethylhexahydro‐s‐triazine as a curing accelerator. The physical properties of the cured product were examined with thermomechanical analysis, thermogravimetric analysis, and dynamic mechanical analysis. Compared with the commercial diepoxide ERL‐4221 under the same curing conditions, the cured product based on II showed a much higher glass‐transition temperature (198 °C), a higher crosslinking density (2.08 × 10^?3 mol/cm³), and a lower coefficient of thermal expansion [6.2 × 10⁵(/°C)]. II may become a promising candidate material for modern microelectronic packaging. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2799–2804, 2001     

Synthesis and characterization of fluorinated poly(amide imide)s derived from 1,4‐bis(2′‐trifluoromethyl‐4′‐trimellitimidophenoxy)benzene and aromatic diamines

A series of fluorinated poly(amide imide)s were prepared from 1,4‐bis(2′‐trifluoromethyl‐4′‐trimellitimidophenoxy)benzene and various aromatic diamines [3,3′,5,5′‐tetramethyl‐4,4′‐diaminediphenylmethane, α,α‐bis(4‐amino‐3,5‐dimethyl phenyl)‐3′‐trifluoromethylphenylmethane, 1,4‐bis(4′‐amino‐2′‐trifluoromethylphenoxy)benzene, 4‐(3′‐trifluoromethylphenyl)‐2,6‐bis(3′‐aminophenyl)pyridine, and 1,1‐bis(4′‐aminophenyl)‐1‐(3′‐trifluoromethylphenyl)‐2,2,2‐trifluoroethane]. The fluorinated poly(amide imide)s, prepared by a one‐step polycondensation procedure, had good solubility both in strong aprotic solvents, such as N‐methyl‐2‐pyrrolidinone, dimethylacetamide, dimethylformamide, dimethyl sulfoxide, and cyclopentanone, and in common organic solvents, such as tetrahydrofuran and m‐cresol. Strong and flexible polymer films with tensile strengths of 84–99 MPa and ultimate elongation values of 6–9% were prepared by the casting of polymer solutions onto glass substrates, followed by thermal baking. The poly(amide imide) films exhibited high thermal stability, with glass‐transition temperatures of 257–266 °C and initial thermal decomposition temperatures of greater than 540 °C. The polymer films also had good dielectric properties, with dielectric constants of 3.26–3.52 and dissipation factors of 3.0–7.7 × 10^?3, and acceptable electrical insulating properties. The balance of excellent solubility and thermal stability associated with good mechanical and electrical properties made the poly(amide imide)s potential candidates for practical applications in the microelectronics industry and other related fields. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1831–1840, 2003     

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     

Novel heterocyclic poly(pyridine‐imide)s with unsymmetric carbazole substituent and noncoplanar structure: High thermal,mechanical and optical transparency,electrochemical, and electrochromic properties

A diamine containing heterocyclic pyridine and unsymmetrical carbazole substituents, 4‐(9‐ethyl‐3‐carbazole)‐2,6‐bis(4‐aminophenyl)pyridine ( CBAPP ), was prepared for use in the synthesis of poly(pyridine‐imide)s PI‐1–8 by direct polycondensation with dianhydrides in N,N‐dimethylacetamide (DMAc). The poly(pyridine‐imide)s derived from the diamine are highly soluble in solvents such as N‐Methyl‐2‐pyrrolidone (NMP) and DMAc at room temperature. Noncoplanar polyimide (PI‐1) showed excellent solubility, high transparency, and high‐performance mechanical properties. These polymers had relatively high glass transition temperatures and exhibited good thermal stability in both nitrogen (T_d10 > 470 °C) and air (T_d10 > 450 °C). The PI‐3～5 cannot form flexible and tough films due to the unsymmetrical carbazole moiety, rigid structure, and polar–polar interaction. However, through copolymerization technique these polymers (PI‐6～8) could be enhanced through the solubility, mechanical, and thermal properties. The optical properties included a strong orange fluorescence (540 nm) after protonation with acid. When the HCl concentration was increased, a new absorption band at approximately 350 nm appeared, and the intensity of the fluorescent peak at 380 nm observed in the neutral polymer solution decreased, along with the appearance of the new fluorescent peak at 540 nm. The poly(pyridine‐imide)s presented here showed only slight fluorescence quenching in the presence of methanol. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 405–412     

Synthesis and characterization of novel polyamide‐imides containing noncoplanar 2,2′‐dimethyl‐4,4′‐biphenylene unit

A new diimide‐dicarboxylic acid, 2,2′‐dimethyl‐4,4′‐bis(4‐trimellitimidophenoxy)biphenyl (DBTPB), containing a noncoplanar 2,2′‐dimethyl‐4,4′‐biphenylene unit was synthesized by the condensation reaction of 2,2′‐dimethyl‐4,4′‐bis(4‐minophenoxy)biphenyl (DBAPB) with trimellitic anhydride in glacial acetic acid. A series of new polyamide‐imides were prepared by direct polycondensation of DBAPB and various aromatic diamines in N‐methyl‐2‐pyrrolidinone (NMP), using triphenyl phosphite and pyridine as condensing agents. The polymers were produced with high yield and moderate to high inherent viscosities of 0.86–1.33 dL · g⁻¹. Wide‐angle X‐ray diffractograms revealed that the polymers were amorphous. Most of the polymers exhibited good solubility and could be readily dissolved in various solvents such as NMP, N,N‐dimethylacetamide (DMAc), N,N‐dimethylformamide (DMF), dimethyl sulfoxide, pyridine, cyclohexanone, and tetrahydrofuran. These polyamide‐imides had glass‐transition temperatures between 224–302 °C and 10% weight loss temperatures in the range of 501–563 °C in nitrogen atmosphere. The tough polymer films, obtained by casting from DMAc solution, had a tensile strength range of 93–115 MPa and a tensile modulus range of 2.0–2.3 GPa. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 63–70, 2001     

Synthesis and characterization of new soluble cardo polyamide‐imides containing cyclododecyl groups

A new cardo diimide‐dicarboxylic acid, 1,1‐bis[4‐(4‐trimellitimidophenoxy)phenyl]cyclododecane (BTPCD), containing a pendant cyclododecyl group was synthesized by the condensation reaction of 1,1‐bis[4‐(4‐aminophenoxy)phenyl]cyclododecane with trimellitic anhydride in glacial acetic acid. A series of new cardo polyamide‐imides were prepared by the direct polycondensation of BTPCD and various aromatic diamines in N‐methyl‐2‐pyrrolidinone (NMP) with triphenyl phosphite and pyridine as condensing agents. The polymers were produced in high yields and with moderate‐to‐high inherent viscosities of 0.72–1.02 dL g⁻¹. The number‐average and weight‐average molecular weights of the polymers ranged from 21,000 to 49,000 and 58,000 to 92,000, respectively. All the polymers exhibited excellent solubility and could be readily dissolved in various solvents such as NMP, N,N‐dimethylacetamide, N,N‐dimethylformamide, dimethyl sulfoxide, pyridine, cyclohexanone, and tetrahydrofuran. These polyamide‐imides had glass‐transition temperatures between 241 and 262 °C and 10% weight‐loss temperatures ranging from 469 to 511 °C in nitrogen. The polymer films had a tensile strength range of 79–108 MPa, an elongation at break range of 7–14%, and a tensile modulus range of 2.0–2.4 GPa. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2787–2793, 2000