Synthesis and characterization of polyazomethine conducting polymers and oligomers

Conjugated polyazomethine polymers were prepared from the polycondensation of terephthalaldehyde with 4,4′-thiodianiline, and 4,4-thiodibenzaldehyde with 4,4′-thiodianiline, 4,4′-phenylenediamine and benzidine. The polymers showed good stability in air and were soluble in many organic solvents. The electrical conductivities of the undoped and doped (H₂SO₄ and I₂) polymers were studied. Doping the polymers markedly increased their conductivities from 10^?8 ? 10^?11 S cm^?1 (dielectric region) to 10^?3 ? 10^?5 S cm^?1 (semiconducting region). The polymers were characterized by IR spectroscopy, elemental analyses, viscosity measurements and X-ray diffraction. Furthermore, polyazomethine oligomers were prepared and a comparative study of the physical properties of the oligomers and their corresponding polymers was performed. The electrical behavior of the oligomers was studied. It was found that oligomers with a minimum of eight aromatic (Ar) rings gave almost the same electrical conductivities as long-chain polymers.     

Synthesis,characterization, optical and electrical properties of thermally stable polyazomethines derived from 4,4′-oxydianiline

Three soluble, thermally stable azomethine polymers were synthesized by the oxidative polycondensation of azomethine bisphenols using NaOCl as an oxidant in aqueous alkaline medium. The azomethine bisphenol monomers, 4,4′-oxybis[N-(2-hydroxy-3-methoxybenzilidine)aniline], 4,4′-oxybis[N-(2-hydroxy-5-bromobenzilidine)aniline] and 4,4′-oxybis[N-(2-hydroxynaphthalidine) aniline] were synthesized by the condensation of 4,4′-oxydianiline with three aromatic aldehydes. The structures of the monomers and polymers were confirmed by Fourier Transform infrared spectroscopy, UV–visible, ¹H-NMR and ¹³C-NMR spectroscopic techniques. Morphology of the synthesized polymers was characterized using scanning electron microscope. The thermal stability of the polymers is evidenced by high carbines residue obtained in TGA. Fluorescence spectra showed that the emission maxima centred in the region 420–460 nm for all the compounds with large stokes shift values (?λ_ST). Electrical conductivity of iodine-doped polymers was measured by four-point probe technique. The synthesized polymers have shown good electrical conductivity on iodine doping, and it increases with the increase in iodine vapour contact time. The self-extinguishing property of the synthesized polymers was studied by the calculation of the limiting oxygen index values with van Krevelen’s equation.     

Synthesis,Characterization, and Conducting Properties of Poly(thiourea azomethines)

Three new polyazomethines having phenylthiourea groups were synthesized through solution polycondensation of terephthalaldehyde with 4,4′-bis(thiourea)biphenyl ether, 4,4′-bis(thiourea)biphenylmethane, and 4,4′-bis(thiourea)biphenyl sulphone. For comparison purposes, simple polyazomethines were prepared by the polycondensation of terephthalaldehyde with 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylmethane, and 4,4′-diaminodiphenyl sulphone. Poly(imine)s having phenylthiourea groups were characterized through IR and ¹H-NMR spectroscopic methods and the thermal stability of the polymers were evaluated through TGA analysis. Conductivity of polyaniline synthesized in aqueous p-toluenesulfonic acid was found to be 3.83 Scm^?1. The conductivity of the polymeric blends with polyaniline dopped with p-toluenesulfonic acid and HCl (20% by weight) were found to be in the range 0.16 × 10^?3 ? 5.7 × 10^?3 Scm^?1.     

Three d10 coordination polymers based on rigid ligands with flexible functional groups: Syntheses,structures and luminescence

Three coordination polymers, namely, {[Zn(L)(BPY)]·DMF·H₂O}_n (1), {[Zn(L)(TPY)]·0.5H₂BDC·H₂O}_n (2), {[Cd(L)(H₂O)₂]·DMF}_n (3), have been synthesized based on a rigid linear carboxylate ligand (H₂L = 2′,5′-dimethoxy-[1,1′:4′,1″-terphenyl]-4,4″-dicarboxylic acid) and different lengths of pyridine ligands (TPY = 4,3′:5′,4″-terpyridine; BPY = 4,4′-bipyridine). These complexes have been characterized by single crystal X-ray diffraction, infrared spectroscopy, thermogravimetry, elemental analysis, and powder X-ray diffraction measurements. Complex 1 is a 6-connected 3-fold interpenetrating pcu net with point symbol {4¹² ∙ 6³}, 2 and 3 can be simplified as 4-connected sql nets with point symbol {4⁴ ∙ 6²}. In addition, their photoluminescent properties are also investigated in detail.     

Highly fluorinated poly(ether‐imide)s derived from 2,2′‐bis(3,4,5‐trifluorophenyl)‐4,4′‐diaminodiphenyl ether and aromatic dianhydrides

A new diamine, 2,2′‐bis(3,4,5‐trifluorophenyl)‐4,4′‐diaminodiphenyl ether (FPAPE) was synthesized through the Suzuki coupling reaction of 2,2′‐diiodo‐4,4′‐dinitrodiphenyl ether with 3,4,5‐trifluorophenylboronic acid to produce 2,2′‐bis(3,4,5‐trifluorophenyl)‐4,4′‐dinitrodiphenyl ether (FPNPE), followed by palladium‐catalyzed hydrazine reduction of FPNPE. FPAPE was then utilized to prepare a novel class of highly fluorinated all‐aromatic poly(ether‐imide)s. The chemical structure of the resulting polymers is well confirmed by infrared and nuclear magnetic resonance spectroscopic methods. Limiting viscosity numbers of the polymer solutions at 25 °C were measured through the extrapolation of the concentrations used to zero. M_n and M_w of these polymers were about 10 000 and 25 000 g mol^?1, respectively. The polymers showed a good film‐forming ability, and some characteristics of their thin films including color and flexibility were investigated qualitatively. An excellent solubility in polar organic solvents was observed. X‐ray diffraction measurements showed that the fluoro‐containing polymers have a nearly amorphous nature. The resulting polymers had T_g values higher than 340 °C and were thermally stable, with 10% weight loss temperatures being recorded above 550 °C. Based on the results obtained, FPAPE can be considered as a promising design to prepare the related high performance polymeric materials. Copyright © 2011 Society of Chemical Industry     

New polymer syntheses: II. Preparation of aromatic poly(ether ketone)s from silylated bisphenols

Bulk condensations of 4,4′-difluorobenzophenone and various silylated bisphenols were carried out at 220°–320°C, with caesium fluoride as catalyst. Silylated bisphenol-A, tetramethylbisphenol-A, 1,1-bis(4-hydroxyphenyl)cyclohexane or 4,4′-dihydroxydiphenylsulphone as monomers and glassy polymers were soluble in several organic solvents. Their glass transitions were determined by differential scanning calorimetry (d.s.c.) and their number molecular weights ($\text{M}\text{?}{}_{\mathrm{<mtext>n</mtext>}}$) determined by means of vapour pressure osmometry. M_n's up to 10 000 were obtained. When silylated hydroquinone, 4,4′-dihydroxydiphenyl, 2,7-dihydroxynaphthalene or 4,4′-dihydroxydiphenylsulphide undergo polycondensation the resulting poly (ether ketone)s form crystals. It is demonstrated that transesterification does not take place and that block copoly(ether ketone-ether sulphone)s are synthesized. Furthermore, the thermostability of the poly(ether ketone)s in air was investigated.     

Arylidene polymers. XVIII. Synthesis and thermal behavior of organometallic arylidene polyesters containing ferrocene derivatives in the main chain

A new interesting category of organometallic polyesters based on diarylidenecycloalkanones containing ferrocene derivatives in the polymer main chain has been prepared by interfacial polycondensation of 1,1′-dichlorocarbonyl ferrocene or 1,1′-dichlorocarbonyl-4,4′-diiodoferrocene with 2,5-bis(p-hydroxybenzylidene)cyclopentanone, 2,5-divanillylidenecyclopentanone, 2,6-bis(p-hydroxybenzylidene)cyclohexanone, 2,6-divanillylidenecyclohexanone, and 2,7-bis(p-hydroxybenzylidene) cycloheptanone. The resulting polyesters were characterized by elemental analyses, infrared spectroscopy, solubility, and viscometry measurements. The thermal behavior of the synthesized polymers was evaluated by thermal gravimetric analysis and correlated with their structures. The crystallinity of all polymers were examined by x-ray diffraction analysis. Moreover, the electrical conductivity of a selected example of polymer was investigated above the temperature range (300–500 K) and showed that it followed an Arrhenius-type equation with activation energy 2.09 eV. © 1993 John Wiley & Sons, Inc.     

Synthesis and characterization of thermotropic liquid crystalline poly(azomethine ether)s

Two series of monomers, namely 4,4′-diformyl-α,ω-diphenoxydecane and 4,4′-diformyl-3,3-methoxy-α,ω-diphenoxydecane, were prepared from 1,10-dibromodecane with p-hydroxybenzaldehyde and 4-hydroxy-3-methoxybenzaldehyde (vanillin), respectively. The poly(azomethine ether)s were prepared by solution polycondensation using 4,4′-diformyl-α,ω-diphenoxydecane, 4,4′-diformyl-3,3-methoxy-α,ω-diphenoxydecane with various diamines. The monomers and polymers were characterized by intrinsic viscosity, FT-IR, ¹H, and ¹³C NMR spectroscopy. The thermogravimetric analysis reveals that the polymers are stable up to 320-500 °C and decomposed with good char yield. The thermotropic liquid crystalline properties of the polymers were examined by differential scanning calorimetry (DSC) and their textures observed under hot stage optical polarized microscopy (HOPM). All the polymers were exhibited thermotropic liquid crystalline properties except tetramethylene diamines-based polymers.     

Part 14. Synthesis and properties of new polyketoamine polymers containing cycloalkanone moieties in the main chain

A new interesting class of polyketoamine polymers based on diarylidenecycloalkanone were synthesized by suspension polycondensation. These polymers were synthesized via polymerization of 2,5‐bis(4‐chloroacetylbenzylidene)cyclopentanone and 2,6‐bis(4‐chloroacetylbenzylidene)cyclohexanone with different aliphatic and aromatic diamines including, p‐phenylenediamine, m‐phenylenediamine, o‐phenylenediamine, 4,4′‐diaminodiphenylmethane, 4,4′‐diaminodiphenylether, 4,4′‐diaminodiphenylsulfone, hydrazine hydrate, 1,2‐diaminoethane, 1,3‐diaminopropane and 1,8‐diaminooctane. Model compounds were prepared by condensation of 2,5‐bis(4‐chloroacetylbenzylidene)cyclopentanone and/or 2,6‐bis(4‐chloroacetylbenzylidene)cyclohexanone with aniline in dry benzene, and their structure was confirmed by elemental analysis and spectroscopy. The structure of the polymers obtained was also confirmed by the same methods. Moreover, the identification of the polymers was carried out by other techniques, eg crystallinity from X‐ray spectroscopy, viscosimetry, thermogravimetric analysis; the morphological properties of selected examples were tested by scanning electron microscopy. The electrical conductivity of selected examples is about 10^?12 ohm cm^?1. The results are in accord with the structure. © 2002 Society of Chemical Industry     

Thermal stability,solubility, and fluorescence property of poly(arylene ether ketone)s bearing <Emphasis Type="Italic">N</Emphasis>-arylenebenzimidazole units

A series of novel random poly(arylene ether ketone)s containing N-arylenebenzimidazolyl groups with precise structures in high yields were synthesized from 2-(2′-hydroxyphenyl) benzimidazole and 4,4′-dihydroxybenzophenone with 4,4′-difluorobenzophenone via nucleophilic substitution polycondensation reaction using sulfolane as a solvent. The reaction was carried out at 210 °C in the presence of anhydrous potassium carbonate. The structures of the resulted polymers were characterized by means of FT-IR, ¹H NMR spectroscopy, and elemental analysis, and the results were largely consistent with the proposed structure. X-ray diffraction studies revealed that the incorporation of N-arylenebenzimidazolyl groups decreased the crystallinity of the resulted polymers. As the benzimidazole unit content in the copolymer increased, the solubility and thermal behavior of the prepared polymers improved. The novel poly(arylene ether ketone)s exhibited glass transition temperatures (T _gs) in the range 188–237°C, and there was a good linearity relationship between T _g values and the content of benzimidazolyl groups. The 5% decomposition temperatures were within the range of 512–539 °C in nitrogen and 496–540 °C in air indicating their good thermal stability. Tensile tests of the films showed that these polymers have desirable mechanical properties. Moreover, the resulting polymers showed good fluorescence properties.     

Synthesis of pyrrones based on the reduction and cyclization of their o-nitrosubstituted polyimides precursors

Pyrrones derived from 1,2,4,5-tetraaminobenzene and pyromellitic dianhydride or 3,3′,4,4′-benzophenonetetracarboxylic dianhydride were prepared by catalytic reduction and cyclization of the poly(o-nitro)imides, obtained by polycondensation of 1,3-dichloro-4,6-dinitrobenzene with the dipotassium salt of pyromellitic diimide or 3,3′,4,4′-benzophenonetetracarboxylic diimide. These polymers were characterized by slightly better thermal stability as compared with the polymers of the same structure obtained by conventional methods. The model compound for these polymers has been also synthesized by catalytic reduction and cyclization of 1,3-bis(phthalimido)-4,6-dinitrobenzene.     

Synthesis and characterization of polyphenylene vinylenes having <Emphasis Type="Italic">m</Emphasis>-terphenyl group: comparison of their optical properties

A series of alternate block copolymers of polyphenylene vinylenes that have 1,3-dioctyloxy phenylene in the center of kinked m-terphenyl group as one of the building blocks with either one of the aromatic groups, viz., 1,4-dioctyloxy benzene, 4,6-dioctyloxy benzene and 4,4′-dioctyloxy biphenyl, was synthesized through Heck polymerization. These alternate block copolymers, viz., poly(2,5-bis(octyloxy)phenylene vinylene alt 4′,6′-bis(octyloxy)-1,1′:3′,1″-terphenylene) (P1), poly(2,4-bis(octyloxy)phenylene vinylene alt 4′,6′-bis(octyloxy)-1,1′:3′,1″-terphenylene) (P2) and poly(4,4′-bis(octyloxy-3,3′-biphenylene vinylene alt 4′,6′-bis(octyloxy)-1,1′:3′,1″-terphenylene) (P3), were characterized for their thermal and optical properties. The synthesized polymers had good solubility in organic solvents and were stable up to 350 °C. The molecular weights of the synthesized polymers were in the range 4370–10,900 Da with polydispersity range 1.52–1.65, which were measured by the gel permeation chromatography technique. The optical properties of these polymers showed absorptions in solution at around 400, 329, and 345 nm for P1, P2, and P3 polymers, respectively. The photoluminescence emission maxima of the polymers were at around 461 nm with a shoulder 439 and 424 nm for P1, P2, and P3, respectively. Photoluminescence emission of films of these polymers showed minimum redshift (20 nm) when compared with spectra of their solutions. The optical and photoluminescence emission properties of these polymers were found to vary on the backbone structure.     

Synthesis and memory characteristics of polyimides containing noncoplanar aryl pendant groups

A series of soluble aromatic polyimides were prepared from 2,2′-diphenyl-4,4′-biphenyl diamine (DPBD), 2,2′-bis(biphenyl)-4,4′-biphenyl diamine (BBPBD), 2,2′-bis[4-(naphthalen-1-yl)phenyl]-4,4′-biphenyl diamine (BNPBD) and 2,2′-bis(3,5-dimethoxyphenyl)-4,4′-biphenyl diamine (BMPBD) by polycondensation with 2,2′-bis[4′-(3′′,4′′,5′′-trifluorophenyl)phenyl]-4,4′,5,5′-biphenyl tetracarboxylic dianhydride via a two-step procedure. The resulting polymers were fully characterized and they exhibited excellent organosolubility, high thermal and dimensional stability. Resistive switching devices with the configuration of Al/polymer/ITO were constructed from these polyimides by using conventional solution coating process. Devices with the active layer based on DPBD, BBPBD and BNPBD exhibited nonvolatile and rewritable flash type memory characteristics with the turn-on voltage at ?2.0 to ?3.0 V and the turn-off voltage at 2.0–3.0 V. Whereas, device based on BMPBD demonstrated a bipolar write-once read-many times (WORM) memory capability with the writing voltage around ±3.0 V. The ON/OFF current ratio of these devices was of about 10⁶ and the retention times can be as long as 10⁴ s.     

Interfacial Polymerization of Linear Aromatic Poly(ester amide)s

Linear aromatic poly(ester amide)s (PEAs) have been synthesized by interfacial polycondensation (IPC) of aromatic diamidoacid chloride: 2-{[4-({[2-(chlorocarbonyl) phenyl]amino} carbonyl) benzoyl]amino} benzoyl chloride (2CCBC), with ethylene glycol, bisphenol A, resorcinol, 4,4′-bis(4-hydroxybenzilidine)diaminobenzanilide and 4,4′-bis(4-hydroxy benzilidine)-m-phenylenediamine in chloroform/water system employing phase-transfer-catalyst. The aromatic diamidoacid chloride has been prepared by condensation of terephthaloyl chloride with anthranilic acid. These polymers were characterized by elemental analysis, FTIR, ¹H-NMR, solubility studies, intrinsic viscosity and TGA analysis. The polyester-amides so obtained show good thermal stability.     

Synthesis,characterization, and comparison of properties of novel fluorinated poly(imide siloxane) copolymers

Four new poly(imide siloxane) copolymers were prepared by a one‐pot solution imidization method at a reaction temperature of 180°C in ortho‐dichlorobenzene as a solvent. The polymers were made through the reaction of o‐diphthaleic anhydride with four different diamines—4,4′‐bis(p‐aminophenoxy‐3,3″‐trifluoromethyl) terphenyl, 4,4′‐bis(3″‐trifluoromethyl‐p‐aminobiphenyl ether)biphenyl, 2,6‐bis(3′‐trifluoromethyl‐p‐aminobiphenyl ether)pyridine, and 2,5‐bis(3′‐trifluoromethyl‐p‐aminobiphenylether)thiopene—and aminopropyl‐terminated poly dimethylsiloxane as a comonomer. The polymers were named 1a , 1b , 1c , and 1d , respectively. The synthesized polymers showed good solubility in different organic solvents. The resulting polymers were well characterized with gel permeation chromatography, IR, and NMR techniques. ¹H‐NMR indicated that the siloxane loading was about 36%, although 40 wt % was attempted. ²⁹Si‐NMR confirmed that the low siloxane incorporation was due to a disproportionation reaction of the siloxane chain that resulted in a lowering of the siloxane block length. The films of these polymers showed low water absorption of 0.02% and a low dielectric constant of 2.38 at 1 MHz. These polyimides showed good thermal stability with decomposition temperatures (5% weight loss) up to 460°C in nitrogen. Transparent, thin films of these poly(imide siloxane)s exhibited tensile strengths up to 30 MPa and elongations at break up to 103%, which depended on the structure of the repeating unit. The rheological properties showed ease of processability for these polymers with no change in the melt viscosity with the temperature. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Two new luminescent Cd(II)/Zn(II) metal–organic frameworks for exceptionally selective detection of picric acid explosives

Two new coordination polymers, {[Cd(BIDPT)(oba)]·0.5H₂O}_n (1) and {[Zn(BIDPT)(4,4′-sdb)]·2.25H₂O}_n (2) (BIDPT = 4,4′-bis(imidazol-l-yl)diphenyl thioether, H₂oba = 4,4′-oxydibenzoic acid, 4,4′-H₂sdb = 4,4′-sulfonyldibenzoic acid), have been solvothermally synthesized and characterized. Both 1 and 2 show 2-fold interpenetrating 3D frameworks with {6⁵ ∙ 8} cds and {6⁶} dia topology, respectively. These two coordination polymers show strong luminescence and their luminescence could be quenched by a series of nitro explosives. Importantly, they exhibit very highly sensitive and selective detection of picric acid compared to other nitro explosives.     

Polymerization of N,N′-bismaleimido-4,4′-diphenylmethane with arenedithiols. Synthesis of some new polyimidosulphides

Two new polyimidosulphides were prepared in 94% yield or higher and with inherent viscosities as high as 1.45 dl g^?1 (0.5 g polymer/100 ml dimethyl sulphoxide; 25°C) by the addition of 4,4′-dimercaptodiphenylether or 4,4′-dimercaptobiphenyl to N,N′-bismeleimido-4,4′-diphenylmethane. Formation of soluble species requires a solvent that is or contains a proton source, since crosslinked products results otherwise. The polymers are amorphous thermoplastics with rigid backbones, reflected by their high glass transition temperatures (T_g = 185°–212°C) as well as by their insolubility in all but highly polar media, such as dimethyl sulphoxide of N,N-dimethylformamide. Both polyimidosulphides, when heated under nitrogen or air (thermogravimetric analysis), show no weight loss up to about 350°C, but the polymers degrade catastrophically (apparently via base-catalysed thiol elimination) within minutes at room temperature when dissolved in aprotic solvents containing secondary or tertiary amines.     

Synthesis and characterization of novel aromatic-aliphatic poly(amide-imide-imide)s (PAII)

Novel poly(amide-imide-imide)s (PAII) were prepared by polycondensation of a new monomer synthesized from trimellitic anhydride and glutamic acid, followed by reflux condensing with thionyl chloride and several diamines. Polymers and monomers were characterized by ¹H NMR and FT-IR spectroscopy, elemental analysis and mass spectrometry. Inherent viscosities of the resulting polymers were in the range of 17–26 mL g^–1 (M_w 13 400–29 160, polydispersity (M_w/M_n) ca. 1.3–1.7), representing rather low molecular weights. The glass transition temperatures of the polymers were in the range of 210–285°C depending on the structure of diamines, and the thermal stability of the polymers was up to 400°C, comparable with that of polyimides and poly(amide imide)s. All the polymers synthesized are well soluble in aprotic polar solvents such as dimethylformamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone and dimethylacetamide. Particularly, polymers containing oxydianiline and 4,4′-diaminodiphenyl sulfone were quite soluble in m-cresol, pyridine, nitrobenzene and tetrahydrofuran.     

Synthesis and characterization of novel copolymers of poly(ether ketone ketone) and poly(ether ketone sulfone imide)

A new monomer containing sulfone and imide linkages, bis{4-[4-(p-phenoxyphenylsulfonylphenoxy)benzoyl]-1,2-benzenedioyl}-N,N,N′,N′-4,4′-diaminodiphenyl ether (BPSPBDADPE), was prepared by the Friedel–Crafts reaction of bis(4-chloroformyl-1,2-benzenedioyl)-N,N,N′,N′-4,4′-diaminodiphenyl ether with 4,4′-diphenoxydiphenyl sulfone. Novel copolymers of poly(ether ketone ketone) and poly(ether ketone sulfone imide) were synthesized by electrophilic Friedel–Crafts solution copolycondensation of terephthaloyl chloride with a mixture of DPE and BPSPBDADPE. The polymers were characterized by different physico-chemical techniques. The polymers with 10–25?mol% BPSPBDADPE are semicrystalline and had increased T _gs over commercially available PEEK and PEKK (70/30) due to the incorporation of sulfone and imide linkages in the main chains. The polymer IV with 25?mol% BPSPBDADPE had not only high T _g of 194?°C but also moderate T _m of 338?°C, having good potential for melt processing and exhibited high thermal stability and good resistance to common organic solvents.     

Poly(P-benzoquinono)diimidazoles from two-ring aromatic dicarboxylic acids

New poly(p-benzoquinono)diimidazoles have been synthesized by one-stage polycondensation in polyphosphoric acid of 2,3,5,6-tetraamino-p-benzoquinone with diphenyl-4,4′-dicarboxylic acid, diphenylmethane-4,4′-dicarboxylic acid, 4,4′-oxydibenzoic acid, and 4,4′-sulfonyldibenzoic acid. The polymers were characterized by infrared and ultraviolet spectral study, viscometric measurements, and thermal analysis. The effects of introducing flexibilizing links such as ? CH₂? ,? O? , and ? SO₂? in the backbone of the polymers, on their thermal stability and solubility were studied.