New organosoluble and thermally stable poly(amide‐imide)s with benzoxazole or benzothiazole pendent groups: synthesis and characterization

Two new benzoxazole or benzothiazole‐containing diimide‐dicarboxylic acid monomers, such as 2‐[3,5‐bis(N‐trimellitimidoyl)phenyl]benzoxazole ( 2 _o ) or 2‐[3,5‐bis(N‐trimellitimidoyl)phenyl]benzothiazole ( 2 _s ) were synthesized from the condensation reaction between 3,5‐diaminobenzoic acid and 2‐aminophenol or 2‐aminothiophenol in polyphosphoric acid (PPA) with subsequent reaction of trimellitic anhydride in the presence of glacial acetic acid, respectively, and two new series of modified aromatic poly(amide‐imide)s were prepared. This preparation was done with pendent benzoxazole or benzothiazole units from the newly synthesized diimide‐dicarboxylic acid and various aromatic diamines by triphenyl phosphite‐activated polycondensation. In addition, the corresponding unsubstituted poly(amide‐imide)s were prepared under identical experimental conditions for comparative purposes. Characterization of polymers was accomplished by inherent viscosity measurements, FT‐IR, UV–visible, ¹H‐NMR spectroscopy and thermogravimetry. The polymers were obtained in quantitative yields with inherent viscosities between 0.39 and 0.81 dl g^?1. The solubilities of modified poly(amide‐imide)s in common organic solvents as well as their thermal stability were enhanced compared to those of the corresponding unmodified poly(amide‐imide)s. The glass transition temperature, 10% weight loss temperature, and char yields at 800°C were, respectively, 7–26°C, 17–46°C and 2–5% higher than those of the unmodified polymers. Copyright © 2010 John Wiley & Sons, Ltd.     

New thermally stable and organosoluble heterocyclic poly(naphthaleneimide)s

As majority of polyheteroarylenes based on bis(naphthalic anhydrides), are difficult to process due to their infusiblity and insolubility in common organic solvents and solubility only in strong acids, this study is concerned with the synthesis and properties of new, easily processable polyimides and copolyimides containing naphthalene and oxadiazole rings. These polymers have been synthesized and their properties have been compared with regard to the influence of oxadiazole and naphthalene units on their physical properties. The polyimides were prepared by polycondensation reaction in solution of the aromatic diamines containing preformed oxadiazole ring with two dianhydrides having naphthalene units, at high temperature. Also, copolyimides were prepared by using a mixture of each naphthalene‐containing dianhydride, with hexafluoroisopropylidene‐dianhydride in the polycondensation reaction with the same diamino‐oxadiazoles. Most of the resulting polyimides and copolyimides were soluble in polar amidic solvents and in less polar solvents, and their solutions gave flexible films when spread onto glass plates. The thermal stability and glass transition temperature of these polyimides and copolyimides were measured and compared. The quality and the roughness of the spin‐coated films of these polymers were investigated by atomic force microscopy. The photoluminescence properties of the polymers in solution were studied to determine the color of emission. The UV absorption was also studied to determine the Stokes shift, and hence the possible reabsorption effects. The properties of the present polyimides make them attractive for applications in advanced optoelectronics and other related fields. Copyright © 2009 John Wiley & Sons, Ltd.     

Synthesis and characterization of thianthrene-containing poly(benzoxazole)s

New thioether- and thianthrene-containing poly(benzoxazole)s (PBOs) were synthesized from 4,4′-thiobis[3-chlorobenzoic acid] and thianthrene-2,7- and -2,8-dicarbonyl chlorides with commercially available bis-o-aminophenols. Polymers were prepared via solution polycondensation in poly(phosphoric acid) at 90–200°C. Transparent PBO films were cast directly from polymerization mixtures or m-cresol. The films were flexible and tough. Non-fluorinated PBOs were soluble only in strong acids and AlCl₃/NO₂R systems by forming complexes with the benzoxazole heterocycle Glass transition temperatures ranged from 298–450°C, and thermogravimetric analysis showed good thermal stabilities in both air and nitrogen atmospheres. © 1995 John Wiley & Sons, Inc.     

Optically transparent,organosoluble poly(ether-amide)s bearing triptycene unit; synthesis and characterization

Abstract

Aromatic polyamides are famous high performance polymeric materials for their excellent thermal, mechanical, electrical properties, which now a days became a dominant platform for modern polymer chemistry area. Triptycene unit like structures in polymer directly affects the physiochemical properties of polymer, thus polyamides especially with triptycene unit in their backbone with aryl ether linkage imparts combination of properties such as better solubility, melts processing characteristics, and better thermal stability in contrast with those of polymers without an aryl-ether linkageNew triptycene-containing bis(ether amine), 1,4-bis(4-aminophenoxy), 2, 3-benzotriptycene (4a) was synthesized from nucleophilic displacement reactions of P-fluoronitrobenzene with 1,4-dihydroxytriptycene, followed by reduction, and elucidated by FTIR, ^1?H, ^13?C NMR spectroscopy and HRMS. A series of new polyamides containing pendant triptycene group and flexibilizing ether linkages was synthesized by polycondensation of diamine with commercially available aromatic diacischlorides viz., terephthalylchloride (TPC), isophthalylchloride (IPC) and varying molar mixture of TPC and IPC accordingly. Synthesized Poly(ether-amide)s were found soluble in common organic solvents such as chloroform, dichloromethane, tetrahydrofuran, DMF, DMAc, DMSO also could be cast into excellent transperent thin films. Inherent viscosities of polyamides were in the range 0.44–0.57 dL/g. Polyamides exhibited initial decomposition temperature (T_i), glass transition temperatures (T_g) and temperature at 10% wt loss (t₁₀), which was determined by TGA were noted in the range 212?°C–305?°C, 295?°C –309?°C and 587?°C–631?°C respectively with 24%–54% char yeild at 900?°C under nitrogen atmosphere, indicating its better thermal stability and moderate glass transition temperature.     

Preparation and characterization of novel organosoluble and thermally stable poly(benzimidazole-amide)s bearing phthalimide pendent groups

Novel aromatic poly(benzimidazole-amide)s, PBAs, have been synthesized by direct polycondensation of a new dicarboxylic acid, N-[3,5-bis(5-carboxylic acid-2-benzimidazole) phenyl]phthalimide (1), containing performed benzimidazole rings and a phthalimide pendent group with various aromatic diamines. The dicarboxylic acid was synthesized by reaction of 5-(N-phthalimide)isophthalic acid with 4-methyl-1,2-phenylenediamine in polyphosphoric acid, followed by its oxidation into relative dicarboxylic acid. To study the structure-property relationships of 1,3-bis(5-carboxylic acid-2-benzimidazole)benzene (2, as a reference) this compound was also synthesized. The chemical structure of 1 and 2 were confirmed by the spectroscopic methods and elemental analyses. The characterization of the polymers was performed with inherent viscosity measurements, solubility tests, FT-IR, Ultraviolet and ¹H NMR spectroscopy and thermogravimetry. The polymers were obtained in quantitative yields with inherent viscosities between 0.53 and 0.91 dl g⁻¹. The effects of the phthalimide pendent group on the polymer properties such as solubility and thermal behavior were investigated and compared with those of the corresponding unsubstituted poly(benzimidazole-amide)s. The modified poly(benzimidazole-amide)s showed enhanced solubilities in some solvents, such as m-cresol and pyridine, in comparison to the unmodified analogues. In addition, the incorporation of the pendent phthalimide groups in the poly(benzimidazole-amide)s backbone increased remarkably the thermal stability of the polymer. The glass transition temperature and 10% weight loss temperature of the poly(benzimidazole-amide)s were in range of 291-334 °C and 466-540 °C, respectively, in nitrogen.     

Thermally stable and organosoluble binaphthylene‐based poly(urea‐ether‐imide)s: one‐pot preparation and characterization

A new family of wholly aromatic poly(urea‐ether‐imide)s ( 4a–4f ) possessing binaphthylene‐twisted rings was prepared by diphenyl azidophosphate (DPAP)‐activated one‐pot polyaddition reaction of a preformed imide heterocyclic ring‐containing dicarboxylic acid, 2,2′‐bis(4‐trimellitimidophenoxy)‐ 1,1′‐binaphthyl ( 1 ) with various kinds of aromatic diamines ( 3a–3f ). At first, with due attention to structural similarity and to compare the characterization data, a model compound 2 was synthesized by the reaction of diimide‐dicarboxylic acid 1 with two mole equivalents of aniline. In this direct method, the polymers were prepared by polyaddition reactions of the in situ‐formed diisocyanate with the aromatic diamines. Molecular weights of the poly(urea‐ether‐imide)s obtained were evaluated viscometrically, and the inherent viscosities (η_inh) measured were in the range 0.10– 0.25 dl/g. All of the polymers were characterized by FT‐IR spectroscopic method and elemental analysis. All of the resulting polymers exhibited an excellent solubility in common polar solvents such as N‐methyl‐2‐pyrrolidone (NMP), dimethyl sulfoxide (DMSO), N,N‐dimethylformamide (DMF), and N,N‐dimethylacetamide (DMAc). Crystallinity of the resulted polymers was evaluated by wide‐angle X‐ray diffraction (WXRD) method, and they exhibited nearly a non‐crystalline nature as evidenced by their diffractograms. The glass transition temperatures (T_g) of the polymers determined by differential scanning calorimetry (DSC) thermograms were in the range of 274–302°C. The temperatures at 10% weight loss (T_d10%) from their thermogravimetric analysis (TGA/DTG) curves were found to be in the range of 389–414°C in nitrogen atmosphere. Copyright © 2008 John Wiley & Sons, Ltd.     

Aromatic poly(benzoxazole)s from multiring diacids containing (phenylenedioxy)diphenylene or (naphthalenedioxy)diphenylene groups: Synthesis and thermal properties

Poly(arylether benzoxazole)s (PAEBOs) were prepared from a series of fully aromatic dicarboxylic acids containing (phenylenedioxy)diphenylene or (naphthalenedioxy) diphenylene groups and 3,3′‐dihydroxy‐4,4′‐diaminobiphenyl (I) or 4‐4′‐(hexafluoroisopropylidene)bis(2‐aminophenol) (II) through high‐temperature direct polycondensation. A phosphorous pentoxide/methanesulfonic acid mixture or trimethylsilylpolyphosphate was used as a condensing agent. All the PAEBOs were amorphous and soluble in strong acids, and those derived from II were also readily soluble in polar organic solvents. Flexible films were cast from their chloroform solutions. The PAEBOs showed inherent viscosity values of 0.68–2.06 dL/g (CH₃SO₃H, T = 30 °C, c = 0.15 g · dL⁻¹). Thermal analysis indicated glass‐transition temperatures ranging from 236 to 270 °C and thermal stability (5% weight loss) in nitrogen up to 526 °C. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1172–1178, 2000     

Novel heat-resistant and organosoluble poly(amide-imide)s containing laterally-attached phenoxy phenylene groups

In this research a new diimide-diacid monomer, 2,2′-bis(4-phenoxyphenyl)-4,4′-bis(N-trimellitoyl)diphenyl ether (BPDPE) containing two laterally-attached phenoxy phenylene groups was prepared by the reaction of 2,2′-bis[(p-phenoxy phenyl)]-4,4′-diaminodiphenyl ether (PPAPE) with trimellitic anhydride in refluxing glacial acetic acid. Ether-hinged wholly aromatic poly(amide-imide)s with limited viscosity number values of 0.61–0.87 dL g⁻¹ were prepared by triphenyl phosphate (TPP)-activated polycondensation of BPDPE with diamines including PPAPE and 4,4′-diaminodiphenyl ether (DADPE). For comparative purposes, reference poly(amide-imide)s were also prepared by reacting diimide-diacid monomer lacking phenoxy phenylene lateral groups namely 4,4′-bis(N-trimellitoyl)diphenyl ether (BTDPE) with the same diamines under similar conditions. A model compound MODEL was also synthesized by the reaction of BTBPE with two mole equivalents of aniline to compare the spectral characteristics results. Number and weight average molecular weights were determined by gel permeation chromatography (GPC) technique. The phenoxy phenylene-containing poly(amide-imide)s (all, except that of resulted from BTDPE and DADPE) had excellent organosolubility in common polar solvents. A low crystallinity extent was only observed using their wide-angle X-ray diffractograms (WAXD). A qualitative study showed the prepared polymers could also be cast into optically-transparent and flexible thin films. The ether-containing lateral groups attached to the ether-hinged macromolecular main chains had no substantial diminishing effect on the thermal stability of these structurally-modified poly(amide-imide)s.     

Novel poly(fluorinated imide)s containing naphthalene pendant group: synthesis and characterization

A new fluorinated diamine monomer containing naphthalene pendant group, bis(4-amino-3,5-difluorophenyl)naphthylmethane (monomer 1), was synthesized from 1-naphthaldehyde and 2,6-difluoroaniline with trifluoromethanesulfonic acid at reflux. The novel poly(fluorinated imide)s (PFIs) were prepared via one-step polycondensation by monomer 1 and three aromatic dianhydrides including 4,4′-oxydiphthalic dianhydride, 3,3′,4,4′-benzophenonetetracarboxylic dianhydride, and 3,3′,4,4′-biphenyltetracarboxylic dianhydride in m-cresol, respectively. The obtained PFIs could be dissolved in a variety of organic solvents such as N-methyl-2-pyrrolidinone, N,N-dimetahylacetamide (DMAC), N,N-dimethylformamide, chloroform, and tetrahydrofuran at room temperature. The highest solubility of PFIs could even reach to 250 mg/mL in chloroform. The PFIs could be easily processed into flexible and tough films by casting onto glass from DMAC solution. The PFI films had a tensile strength, elongation at break, and tensile modulus in the range of 84–102 MPa, 8.7–12.8%, and 2.2–2.8 GPa, respectively. These polymers also showed excellent thermal stability with glass transition temperatures in the range of 326–352 °C, 10% weight loss temperatures in the range of 538–574 °C, and the weight residue more than 57% at 800 °C in nitrogen. Moreover, as for the optical properties, these PFIs exhibited a strong optical absorption in the ultraviolet region (290–370 nm) and photoluminescence in dilute chloroform solution or solid state.     

Synthesis and characterization of novel aromatic poly(imide–benzoxazole) copolymers

New poly(imide–benzoxazole) copolymers were prepared directly from a dianhydride, a diacid chloride, and a bis(o‐diaminophenol) monomer in a two‐step method. In the first step, poly(amic acid–hydroxyamide) precursors were synthesized by low‐temperature solution polymerization in an organic solvent. Subsequently, the thermal cyclodehydration of the poly(amic acid–hydroxyamide) precursors at 350 °C produced the corresponding poly(imide–benzoxazole) copolymers. The inherent viscosities of the precursor polymers were around 0.19–0.33 dL/g. The cyclized poly(imide–benzoxazole) copolymers had glass‐transition temperatures in the range of 331–377 °C. The 5% weight loss temperatures ranged from 524 to 535 °C in nitrogen and from 500 to 514 °C in air. The poly(imide–benzoxazole) copolymers were amorphous, as evidenced by the wide‐angle X‐ray diffraction measurements. The structures of the precursor copolymers and the fully cyclized copolymers were characterized by Fourier transform infrared, ¹H NMR, and elemental analysis. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6020–6027, 2005     

Palladium-catalyzed synthesis of poly(bromoalkoxy- and bromoalkanoyloxymethylsiloxane)s from poly(hydromethylsiloxane)s

Palladium-catalyzed synthesis of poly(bromoalkoxymethyl- and bromoalkanoyloxymethylsiloxane)s from poly(hydromethylsiloxane)s was studied. Treatment of poly(hydromethylsiloxane)s with mixtures of allyl bromide and cyclic ethers in the presence of a catalytic amount of PdCl₂ gave the corresponding poly[(bromoalkoxy)methylsiloxane]s in good yield. A similar reaction with γ-butyrolactone produced poly[(bromobutanoyloxy)methylsiloxane], although the polymer was highly moisture-sensitive and could not be separated from the reaction mixture. Transformation of the bromoalkoxy unit in the resulting siloxane polymer into an aminoalkoxy group was also examined.     

Synthesis and characterization of optically active and organosoluble poly(amide-imide)s containing imidazole rings as pendent groups by direct polycondensation

Six new optically active poly(amide-imide)s(PAIs) 6a-f were prepared by direct polycondensation reaction of N-trimelli-tylimido-L-histidine 4 as a chiral diacid with various aromatic diamines 5a-f.Triphenyl phosphite(TPP)/pyridine(Py) in the presence of calcium chloride(CaCl2) and N-methyl-2-pyrrolidone(NMP) were successfully applied to direct polycondensation reaction.The resulting new polymers were in good yields,and had inherent viscosities ranging between 0.29 and 0.41 dL g-1 and were detected with elem...     

Synthesis and properties of novel cardo aromatic poly(ether‐benzoxazole)s

Three new bis(ether‐acyl chloride) monomers, 1,1‐bis[4‐(4‐chloroformylphenoxy)phenyl]cyclohexane ( 1a ), 5,5‐bis[4‐(4‐chloroformylphenoxy)phenyl]‐4,7‐methanohexahydroindan ( 1b ), and 9,9‐bis[4‐(4‐chloroformylphenoxy)phenyl]fluorene ( 1c ), were synthesized from readily available compounds. Aromatic polybenzoxazoles bearing ether and cardo groups were obtained by the low‐temperature solution polycondensation of the bis(ether‐acyl chloride)s with three bis(aminophenol)s and the subsequent thermal cyclodehydration of the resultant poly(o‐hydroxy amide)s. The intermediate poly(o‐hydroxy amide)s exhibited inherent viscosities in the range of 0.35–0.71 dL/g. All of the poly(o‐hydroxy amide)s were amorphous and soluble in many organic polar solvents, and most of them could afford flexible and tough films by solvent casting. The poly(o‐hydroxy amide)s exhibited glass‐transition temperatures (T_g's) in the range of 141–169 °C and could be thermally converted into the corresponding polybenzoxazoles approximately in the region of 240–350 °C, as indicated by the DSC thermograms. Flexible and tough films of polybenzoxazoles could be obtained by thermal cyclodehydration of the poly(o‐hydroxy amide) films. All the polybenzoxazoles were amorphous and showed an enhanced T_g but a dramatically decreased solubility as compared with their poly(o‐hydroxy amide) precursors. They exhibited T_g's of 215–272 °C by DSC and showed insignificant weight loss before 500 °C in nitrogen or air. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 4014–4021, 2001     

Synthesis and characterization of sulfonated poly(benzoxazole ether ketone)s by direct copolymerization as novel polymers for proton-exchange membranes

A new series of sulfonated poly(benzoxazole ether ketone)s (SPAEKBO-X) were prepared by the aromatic nucleophilic polycondensation of 4,4′-(hexafluoroisopropylidene)-diphenol with 2,2′-bis[2-(4-fluorophenyl)benzoxazol-6-yl]hexafluoropropane and sodium 5,5′-carbonylbis-2-fluorobenzenesulfonate in various ratios. Fourier transform infrared and ¹H NMR were used to characterize the structures and sulfonic acid contents of the copolymers. The copolymers were soluble in N-methyl-2-pyrrolidinone, N,N-dimethylacetamide, and N,N-dimethylformamide and could form tough and flexible membranes. The protonated membranes were thermally stable up to 320 °C in air. The water uptake, hydrolytic and oxidative stability, and mechanical properties were evaluated. At 30–90 °C and 95% relative humidity, the proton conductivities of the membranes increased with the sulfonic acid content and temperature and almost reached that of Nafion 112. At 90–130 °C, without external humidification, the conductivities increased with the temperature and benzoxazole content and reached above 10⁻² S/cm. The SPAEKBO-X membranes, especially those with high benzoxazole compositions, possessed a large amount of strongly bound water (>50%). The experimental results indicate that SPAEKBO-X copolymers are promising for proton-exchange membranes in fuel cells, and their properties might be tailored by the adjustment of the copolymer composition for low temperatures and high humidity or for high temperatures and low humidity; they are especially promising for high-temperature applications. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2273–2286, 2007     

From poly(dialkylstannane)s to poly(diarylstannane)s: comparison of synthesis methods and resulting polymers

The efficiency and applicability of three different methods to synthesize polystannanes with different side chains are described. By means of dehydrogenative coupling utilizing the transition metal catalyst RhCl(PPh₃)₃ (Wilkinson's catalyst), n‐Bu₂SnH₂ reached the highest molar masses. Dehydrogenetive coupling in the presence of tetramethylethylenediamine could be best employed for (4‐n‐BuPh)₂SnH₂. Wurtz coupling using sodium in liquid ammonia was best suited for Ph₂SnCl₂. Next to the above‐mentioned educts, n‐Bu(Ph)SnX₂ (X = H or Cl (as appropriate for the particular route) was used for polymerization resulting in one of so far rare example of asymmetric polystannanes with high molecular masses. Copyright © 2011 John Wiley & Sons, Ltd.     

A novel type of Si-containing poly(urethane-imide)s: synthesis, characterization and electrical properties

A novel type of a Si-containing poly(urethane-imide) (PUI) was prepared by two different methods. In the first method, Si-containing polyurethane (PU) prepolymer having isocyanate end groups was prepared by the reaction of diphenylsilanediol (DSiD) and toluene diisocyanate (TDI). Subsequently the PU prepolymer was reacted with pyromellitic dianhydride (PMDA) or benzophenonetetracarboxylic dianhydride (BTDA) in N-methyl pyrolidone (NMP) to form Si-containing modified polyimide directly. In the second method, PU prepolymer was reacted with diaminodiphenylether (DDE) or diaminodiphenylsulfone (DDS) in order to prepare an amine telechelic PU prepolymer. Finally, the PU prepolymer having diamine end groups was reacted with PMDA or BTDA to form a Si-containing modified polyimide. Cast films prepared by second method were thermally treated at 160 °C to give a series of clear, transparent PUI films. Thermogravimetric analysis indicated that the thermal degradation of PUI starts at 265 °C which is higher than degradation temperature of conventional PU, confirming that the introduction of imide groups improved the thermal stability of PU.To characterize the modified polyimides and their films, TGA, FTIR, SEM and inherent viscosity analyses were carried out. The dielectrical properties were investigated by the frequency-capacitance method. Dielectric constant, dielectric breakdown strength, moisture uptake and solubility properties of the films were also investigated.     

Aminosalicylate-based biodegradable polymers: Syntheses and in vitro characterization of poly(anhydride-ester)s and poly(anhydride-amide)s

Poly(anhydride-ester)s and poly(anhydride-amide)s derived from both 4- and 5-aminosalicylate acids (4- and 5-ASA) were synthesized and characterized by physicochemical methods. Thermal and solubility characteristics directly correlated to the polymer backbone composition; polymers based on 5-ASA had greater solubilities in organic solvents than polymers based on 4-ASA, and the poly(anhydride-ester)s thermally decomposed at temperatures nearly 100 °C higher than the corresponding poly(anhydride-amide)s. The polymers were self-contained, controlled-release systems that combine the drug and controlled-release mechanism into the polymer backbone. The erosion and degradation characteristics of the polymers were measured in physiologically relevant media. All polymer matrices fully degraded in media buffered to pH 7.4, whereas in acidic media (pH 1.2), all polymer matrices maintained greater than 50% mass over a 90-day time period. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3667–3679, 2003     

Soluble poly (aryl ether)s containing naphthalene pendant group: synthesis, characterization and electrospinning

Two soluble poly(aryl ether)s were prepared conveniently from bis(4-hydroxy-3,5-dimethylphenyl)naphthylmethane (1) and two activated dihalide monomers including 4,4′-difluorobenzophenone and bis(4-chlorophenyl)sulfone by an aromatic nucleophilic substitution. The bulky naphthyl and tetramethyl pendant groups in the polymer backbone could decrease the packing density and intermolecular interaction of macromolecular chain and make these poly(aryl ether)s show a good solubility. They all could be dissolved in CHCl₃, CH₂Cl₂ and tetrahydrofuran at room temperature with a dissolvability of more than 10 wt%. Furthermore, the poly(aryl ether)s could be electrospun into microfiber (10–15 μm) with nanopores (200–350 nm). The morphologies of these fibers were characterized by scanning electron microscopy. The porous morphology on the fiber surface was also investigated using scanning probe microscope.