Synthesis,characterization and investigation of proton exchange properties of sulfonated polytriazoles from a new semifluorinated diazide monomer

This work describes the synthesis and characterization of a new series of semifluorinated sulfonated polytriazole copolymers (PTATSH‐XX) with varying degree of sulfonation and higher IEC. The copolymers have been prepared by click reaction using a combination of diazide monomers; a newly synthesized diazide monomer namely 4,4‐bis[3‐trifluoromethyl‐4(4‐azidophenoxy)phenyl]benzene (TAZ) and a commercially available diazide monomer namely 4,4′‐diazido‐2,2′‐stilbenedisulfonic acid disodium salt (DADSDB) with a bis‐alkyne monomer namely 4,4′‐(propane‐2,2‐diyl)bis((prop‐2‐ynyloxy)benzene) (BPEBPA). The copolymers are well characterized by FTIR and NMR spectroscopy and have exhibited good solubility and film forming abilities along with good thermal and chemical stability, low water uptake, good dimensional stability and high mechanical properties. The TEM micrographs of the copolymer membranes show good phase separated morphology with cluster size in the range 10–60 nm. The proton conductivity values of the copolymer membranes are found in the range of 15–90 mS cm^?1 at 80°C and 16–97 mS cm^?1 at 90°C. POLYM. ENG. SCI., 57:312–323, 2017. © 2016 Society of Plastics Engineers     

Hydroquinone Based Sulfonated Copolytriazoles with Enhanced Proton Conductivity

A series of new fluorinated sulfonated copolytriazoles (PTHQSH‐XX) with ion exchange capacity (IEC_w) values ranging from 1.66 to 2.82 meq g⁻¹ are prepared via cuprous ion catalyzed azide‐alkyne click polymerization reaction between 1,4‐bis(prop‐2‐ynyloxy)benzene, 4,4′‐diazido‐2,2′‐stilbene disulfonic acid disodium salt (SA), and 4,4‐bis[3′‐trifluoromethyl‐4′(4‐azidobenzoxy) benzyl] biphenyl (QAZ). The degree of sulfonation of the copolytriazoles is adjusted between 60% and 90% by varying the molar ratio of sulfonated monomer (SA) to the nonsulfonated monomer (QAZ). The structure of the copolytriazoles is characterized by Fourier transform infrared and NMR spectroscopy. The solution‐cast membranes of these copolymers exhibit high thermal, mechanical, oxidative and hydrolytic stability, and high proton conductivity (19–142 mS cm⁻¹ at 80 °C and 22–157 mS cm⁻¹ at 90 °C). Transmission electron microscopy confirms the formation of good phase separated morphology with ionic clusters in the range of 15–145 nm.     

Preparation and characterization of poly(vinyl alcohol)‐poly(vinyl pyrrolidone) blend: A biomaterial with latent medical applications

Aqueous solutions of poly(vinyl alcohol) and poly(vinyl pyrrolidone) are blended and films are produced by casting method with the further intention of being used as bio‐materials with latent medical application. Glutaraldehyde, 4,4′‐diazido‐2,2′‐stilbenedisulfonic acid disodium salt tetra‐hydrate are used as crosslinker agents, whereas lactic acid is the plasticizer in the blend. The obtained films are characterized by differential scanning calorimetry (DSC), mechanical properties, swelling and solubility behavior. DSC measurements show that the blends exhibit a single glass transition temperature indicating that they are miscible, even in the presence of the plasticizer and crosslinker agents. By the combination of all mentioned additives, a relevant enhancement of the swelling is observed, accompanied by a stabilization of the solubility during the tested time. Finally, mechanical properties show an appropriate performance in the studied parameters. As a consequence, the obtained films could be suitable for use as medium or long‐term implants. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Sulfonated poly(ether ether sulfone) copolymers for proton exchange membrane fuel cells

Novel aromatic sulfonated poly(ether ether sulfone)s (SPEESs) with tert‐butyl groups were synthesized by aromatic nucleophilic polycondensation of disodium 3,3′‐disulfonate‐4,4′‐dichlorodiphenylsulfone (SDCDPS), 4,4′‐dichlorodiphenylsulfone (DCDPS), and tert‐butylhydroquinone (TBHQ). The resulting copolymers showed very good thermal stability and could be cast into tough membranes. The morphology of the membranes was investigated with atomic force microscopy. The proton conductivity of SPEES‐40 membranes increased from 0.062 S/cm at 25°C to 0.083 S/cm at 80°C, which was higher than the 0.077 S/cm of Nafion 117 under the same testing conditions. These copolymers are good candidates to be new polymeric electrolyte materials for proton exchange membrane fuel cells. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1443–1450, 2007     

Synthesis and characterization of chemically stable sulfonated copoly(triazole imide)s with high proton conductivity

The synthesis and characterization of a series of new sulfonated copoly(triazole imide)s (PTPQSH‐XX) are reported in this work. The PTPQSH‐XX with different degree of sulfonation (DS) were prepared by click polymerization of equimolar amounts of a diimide‐based dialkyne monomer, namely bis‐N,N′‐(prop‐2‐ynyl)pyromellitic diimide (TP) and a mixture of two different diazide monomers (one sulfonated, 4,4‐bis[3′‐trifluoromethyl‐4′{4‐azidobenzoxy} benzyl] biphenyl, and another nonsulfonated, 4,4′‐diazido‐2,2′‐stilbene disulfonic acid disodium salt [SAZ]), in different molar ratios. The copolymers showed high inherent viscosity (1.12–1.28 dL/g) in n‐methyl pyrrolidone (NMP) indicating the formation of high molar masses. Freestanding membranes were prepared from these copolymers by solution casting method. DS of the copolymers was determined from ¹H NMR signal intensities, and the values were in good agreement with the quantity of SAZ monomer used in polymer feed, indicating the successful incorporation of the sulfonated monomer. The copolymers exhibited high thermal and mechanical stabilities. The PTPQSH‐80 membrane showed proton conductivity as high as 178 mS/cm at 90°C with good oxidative and hydrolytic stability. Cross‐sectional transmission electron microscope micrographs of the membranes indicated phase segregated morphology along with interconnected hydrophilic domains with dimension in the range 15–150 nm. POLYM. ENG. SCI., 59:2279–2289, 2019. © 2019 Society of Plastics Engineers     

A positive‐working photosensitive polyimide based on thermal cross‐linking and acidolytic cleavage

A novel positive‐working photosensitive polyimide (PSPI) based on a poly(hydroxyimide) (PHI), a crosslinking agent having vinyl ether groups, and a photoacid generator (PAG) was prepared. The PHI as a base resin of the three‐component PSPI was synthesized from 4,4′‐oxydiphthalic anhydride and 2,2′‐bis(3‐amino‐4‐hydroxyphenyl)hexafluoropropane through ring‐opening polymerization and subsequent thermal cyclization. 2,2′‐bis(4‐(2‐(vinyloxy)ethoxy)phenyl)propane (BPA‐DEVE) was used as a vinylether compound and diphenyliodonium 5‐hydroxynaphthalene‐1‐sulfonate was used as a PAG. The phenolic hydroxyl groups of the PHI and the vinyl ether groups of BPA‐DEVE are thermally crosslinked with acetal structures during prebake step, and the crosslinked PHI becomes completely insoluble in an aqueous basic solution. Upon exposure to UV light (365 nm) and subsequent postexposure bake (PEB), a strong acid generated from the PAG cleaves the crosslinked structures, and the exposed area is effectively solubilized in the alkaline developer. The dissolution behavior of the PSPI containing each 11.5 wt % of BPA‐DEVE and of the PAG was studied after UV exposure (365 nm) and PEB. It was found that the difference in dissolution rates between exposed and unexposed areas was enough to get high resolution. A fine positive pattern with a resolution of 5 μm in a 3.7‐μm‐thick film was obtained from the three‐component PSPI. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Effects of the solvent polarity on the atom transfer radical polymerization of methyl methacrylate initiated by 4‐(chloromethyl)phenyltrimethoxysilane

The controllability of the atom transfer radical polymerization of methyl methacrylate in the polar solvent N,N‐dimethylformamide and the nonpolar solvent xylene with 4‐(chloromethyl)phenyltrimethoxysilane as an initiator and with CuCl/2,2′‐bipyridine and CuCl/4,4′‐di(5‐nonyl)‐2,2′‐bipyridine as catalyst systems was studied. Gel permeation chromatography analysis established that in the nonpolar solvent xylene, much better control of the molecular weight and polydispersity of poly(methyl methacrylate) was achieved with the CuCl/4,4′‐di(5‐nonyl)‐2,2′‐bipyridine catalyst system than with the CuCl/2,2′‐bipyridine as catalyst system. In the polar solvent N,N‐dimethylformamide, unlike in xylene, the polymerization was more controllable with the CuCl/2,2′‐bipyridine catalyst system than with the CuCl/4,4′‐di(5‐nonyl)‐2,2′‐bipyridine catalyst system. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2751–2754, 2007     

Poly(vinyl alcohol)/poly(vinyl pyrrolidone) interpenetrating polymer network: Synthesis and pervaporation properties

Novel interpenetrating polymer network membranes were made from poly(vinyl alcohol)/poly(vinyl pyrrolidone) blends of different compositions. The two polymer components were independently crosslinked chemically with glutaraldehyde and photochemically with 4,4′‐diazostilbene‐2,2′‐disulfonic acid disodium salt. The membrane performances were studied in pervaporation of tetrahydrofuran (THF)/water and THF/methanol mixtures. It was found that the membranes were excellent in THF dehydration, but much less efficient for the separation of THF/methanol mixtures. The pervaporation results were consistent with the membrane swelling data. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2808–2814, 2003     

Blue‐light‐emitting poly(arylene ethynylenes) containing alternating sequences of biphenylene or fluorenediyl and p‐phenylene moieties linked through triple bonds

Two new poly(arylene ethynylenes) were synthesized by the reaction of 1,4‐diethynyl‐2.5‐dioctylbenzene either with 4,4′‐diiodo‐3,3′‐dimethyl‐1,1′‐biphenyl or 2,7‐diiodo‐9,9‐dioctylfluorene via the Sonogashira reaction, and their photoluminescence (PL) and electroluminescence (EL) properties were studied. The new poly(arylene ethynylenes) were poly[(3,3′‐dimethyl‐1,1′‐biphenyl‐4,4′‐diyl)‐1,2‐ethynediyl‐(2,5‐dioctyl‐1,4‐phenylene)‐1,2‐ethynediyl] (PPEBE) and poly[(9,9‐dioctylfluorene‐2,7‐diyl)‐1,2‐ethynediyl‐(2,5‐dioctyl‐1,4‐phenylene)‐1,2‐ethynediyl] (PPEFE), both of which were blue‐light emitters. PPEBE not only emitted better blue light than PPEFE, but it also performed better in EL than the latter when the light‐emitting diode devices were constructed with the configuration indium–tin oxide/poly(3,4‐ethylenedioxythiophene) doped with poly(styrenesulfonic acid) (50 nm)/polymer (80 nm)/Ca:Al. The device constructed with PPEBE exhibited an external quantum efficiency of 0.29 cd/A and a maximum brightness of about 560 cd/m², with its EL spectrum showing emitting light maxima at λ = 445 and 472 nm. The device with PPEFE exhibited an efficiency of 0.10 cd/A and a maximum brightness of about 270 cd/m², with its EL spectrum showing an emitting light maximum at λ = 473 nm. Hole mobility (μ_h) and electron mobility (μ_e) of the polymers were determined by the time‐of‐flight method. Both polymers showed faster μ_h values. PPEBE revealed a μ_h of 2.0 × 10^?4 cm²/V·s at an electric field of 1.9 × 10⁵ V/cm and a μ_e of 7.0 × 10^?5 cm²/V·s at an electric field of 1.9 × 10⁵ V/cm. In contrast, the mobilities of the both carriers were slower for PPEFE, and its μ_h (8.0 × 10^?6 cm²/V·s at an electric field of 1.7 × 10⁶ V/cm) was 120 times its μ_e (6.5 × 10^?8 cm²/V·s at an electric field of 8.6 × 10⁵ V/cm). The much better balance in the carriers' mobilities appeared to be the major reason for the better device performance of PPEBE than PPEFE. Their highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels were also a little different from each other. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 299–306, 2006     

Synthesis of well‐defined poly(methyl methacrylate) nanoparticles by reverse atom transfer radical polymerization in a microemulsion

Well‐defined poly(methyl methacrylate) (PMMA) with an α‐isobutyronitrile group and an ω‐bromine atom as the end groups was synthesized by the microemulsion polymerization of methyl methacrylate (MMA) at 70°C with a 2,2′‐azobisisobutyronitrile/CuBr₂/2,2′‐bipyridine system. The conversion of the polymerization reached 81.9%. The viscosity‐average molecular weight of PMMA was high (380,000), and the polydispersity index was 1.58. The polymerization of MMA exhibited some controlled radical polymerization characteristics. The mechanism of controlled polymerization was studied. The presence of hydrogen and bromine atoms as end groups of the obtained PMMA was determined by ¹H‐NMR spectroscopy. The shape and size of the final polymer particles were analyzed by scanning probe microscopy, and the diameters of the obtained particles were usually in the range of 60–100 nm. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3670–3676, 2006     

Synthesis and properties of polymeric complexes containing bithiazole rings and carbazole units

A novel polymer (poly[2,2'‐(4,4'‐bithiazolylene)][N‐(2‐ethylhexyl)‐3,6‐carbazylene] (PBTCA) was first synthesized from 2,2′‐diamino‐4,4′‐bithiazole and N‐(2‐ethylhexyl)‐3,6‐diformylcarbazole. The structure of the polymer was determined with IR and ¹H‐NMR spectroscopy. The PBTCA–Nd³⁺ complex was prepared via the mixing of neodymium trichloride hexahydrate and PBTCA in dimethyl sulfoxide under a nitrogen atmosphere. The magnetic behaviors of the Nd³⁺ complex of a poly(Schiff base) were measured as a function of the magnetic field strength (0–50 kOe) at 4 K and as a function of the temperature (4–300 K). The results show that PBTCA–Nd³⁺ is a ferromagnet when the temperature is below 15 K, and above that, it is a diamagnet. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 443–446, 2006     

Synthesis of a novel hexaarylbiimidazole with ether groups and characterization of its photoinitiation properties for acrylate derivatives

A novel photoinitiator 2,2′‐bis‐(2‐chlorophenyl)‐4,4′,5,5′‐tetra‐[3‐(2‐hydroxylmethyl‐2‐triethylene glycol monoethylene ether‐ethane‐1‐oxy)‐phenyl]‐1,2′‐biimidazole (BCTE‐HABI) was synthesized from 3,3′‐dimethoxy benzoin. Ultraviolet spectra, fluorescence spectra, ESR, photodilatometer, and photo‐DSC measurements indicate that its photoinitiating activity for acrylate derivatives is better than 2,2′‐bis‐(2‐chlorophenyl)‐4,4′,5,5′‐tetraphenyl‐1,2′‐biimidazole (o‐Cl‐HABI), which is one of the most widely studied and used derivatives of HABI. POLYM. ENG. SCI., 46:474–479, 2006. © 2006 Society of Plastics Engineers.     

Novel sulfonated poly(arylene biphenylsulfone ether) copolymers containing bisphenylsulfonyl biphenyl moiety: structural,thermal, electrochemical and morphological characteristics

A series of sulfonated poly(arylene biphenylsulfone ether) polymers containing up to two pendant sulfonic acid groups per repeat unit were successfully synthesized from 4,4′‐bis[(4‐chlorophenyl)sulfonyl]‐1,1′‐biphenyl (BCPSBP), disodium 3,3′‐disulfonate‐4,4′‐dichlorodiphenylsulfone (SDCDPS) and bisphenol A via aromatic nucleophilic displacement polycondensation. The resulting polymers were characterized by means of Fourier transform infrared and ¹H NMR spectroscopy, gel permeation chromatography, differential scanning calorimetry and thermogravimetric analysis (TGA). The number‐average molecular weight (M_n) of the synthesized polymers was in the range 15 300–22 900 g mol^?1, and the polydispersity indices (M_w/M_n) varied from 2.5 to 4.4. Tough membranes with SDCDPS/BCPSBP mole ratio up to 50:50 were successfully cast using N‐methyl‐2‐pyrrolidone (NMP). An increase of sulfonic acid groups in the polymer backbone resulted in increased solubility in aprotic polar solvents and glass transition temperature. The TGA curves of all the copolymers in acid form exhibited two distinct weight‐loss profiles. The influential characteristics of the polymer electrolyte membranes, such as tensile strength, water uptake, ion‐exchange capacity and proton conductivity, were characterized with respect to the pendant sulfonic acid groups. Atomic force microscopy phase images of the acid‐form membranes clearly showed the hydrophilic domains, with sizes increasing as a function of the degree of sulfonation. Copyright © 2010 Society of Chemical Industry     

Synthesis of liquid crystalline epoxy and its mechanical and electrical characteristics—curing reaction of LCE with diamines by DSC analysis

An aromatic liquid crystalline epoxy monomer based on biphenyl mesogen was synthesized and cured with three different aromatic diamines. The curing reaction characteristics were analyzed by DSC, and the data were introduced to the Kissinger equation to attain the kinetic parameters. Diglycidyl ether of 4,4′‐biphenyl (DGEBP)/4,4′‐diaminobiphenyl (DABP), and DGEBP/4,4′‐methylenediamine (MDA) systems showed an exotherm curing reaction after comelting of the monomers; the DGEBP/p‐phenylenediamine (PDA) system's curing reaction took place in the solid state without melting of monomers. The activation energy and preexponential factor for the DGEBP/DABP system were 55.6 kJ/mol and 4.0 × 10⁶ min^?1, respectively. Those values for DGEBP/MDA and DGEBP/PDA systems were 55.1 kJ/mol and 1.0 × 10⁶ min^?1 and 148.8 kJ/mol and 7.7 × 10¹⁹ min^?1, respectively. The rate constant at 100°C for DGEBP/PDA is 2 times higher than those for DGEBP/DABP and DGEBP/MDA, which have almost the same values. Strictly speaking, the rate constant of DGEBP/DABP is a little higher than that of DGEBP/MDA, and these results are in good agreement with the DSC curves. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2419–2425, 2002     

Changes of fluorescence color in novel poly(azomethine) by the acidity variation

A novel polymer, poly(4,4′‐oxydiphenylenemethylidynenitrilo‐2,5‐dihexyloxy‐1,4‐phenylenenitrilomethyli‐ dyne) (POPNM), with a azomethine structure, containing long alkoxy side chains, was synthesized by the polycondensation of 2,5‐bis(hexyloxy)terephthalaldehyde with 4,4′‐oxydianiline. It displayed acid‐sensory properties as colorimetric and fluorescent transducers to the strong acid analytes because of the protonation of an imine group in the compound. To examine the sensitivity to the acid, the effect of absorption and fluorescence of the polymer was investigated by simply adding trifluoroacetic acid into a chloroform solution of the polymer, and as a result, the multiple colors of fluorescence were sharply changed. Increasing the amount of the acid, the maximum absorption bands of fluorescence spectra were bathochromically shifted from 470 to 570 nm and, then, treating the pyridine as a base, they were recovered. A polymer film containing both the polymer and a photoacid generator (PAG) was prepared by semi‐interpenetrating network polymerization method. When the polymer film was exposed to UV in the presence of PAG through a photomask, well‐resolved fluorescent image patterns were readily obtained. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1228–1233, 2006     

Preparation and properties of bisphenol A‐based sulfonated poly(arylene ether sulfone) proton exchange membranes for direct methanol fuel cell

Novel bisphenol A‐based sulfonated poly(arylene ether sulfone) (bi A‐SPAES) copolymers were successfully synthesized via direct copolymerization of disodium 3,3′‐disulfonate‐4,4′‐dichlorodiphenylsulfone, 4,4′‐dichlorodiphenylsulfone, and bisphenol A. The copolymer structure was confirmed by Fourier transform infrared spectra and ¹H NMR analysis. The series of sulfonated copolymers based membranes were prepared and evaluated for proton exchange membranes (PEM). The membranes showed good thermal stability and mechanical property. Transmission electron microscopy was used to obtain the microstructures of the synthesized polymers. The membranes exhibit increased water uptake from 8% to 66%, ion exchange capacities from 0.41 to 2.18 meq/g and proton conductivities (25°C) from 0.012 to 0.102 S/cm with the degree of sulfonation increasing. The proton conductivities of bi A‐SPAES‐6 membrane (0.10–0.15 S/cm) with high‐sulfonated degree are higher than that of Nafion 117 membrane (0.095–0.117 S/cm) at all temperatures (20–100°C). Especially, the methanol diffusion coefficients of membranes (1.7 × 10^?8 cm²/s–8.5 × 10^?7 cm²/s) are much lower than that of Nafion 117 membrane (2.1 × 10^?6 cm²/s). The new synthesized copolymer was therefore proposed as a candidate of material for PEM in direct methanol fuel cell. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Bis-azobenzene crosslinkers for photocontrol of peptide structure

Crosslinkers that undergo large changes in length upon photoisomerization can produce large conformational changes, and thereby functional changes, in biomolecules. We have designed and synthesized extended and rigid bis‐azobenzene crosslinkers: 4,4′‐bis(4‐(2‐chloroacetamido)phenyl)diazenylbiphenyl (BPDB) and the water‐soluble sulfonated analogue 4,4′‐bis(4‐(2‐chloroacetamido)phenyl)diazenylbiphenyl‐2,2′‐disulfonate (BPDBS). These photoswitches can produce end‐to‐end distance changes of a minimum of ≈5 Å and a maximum of ≈23 Å upon trans/cis isomerization. They have high absorption coefficients (45–60 000 M ^?1 cm^?1) and can produce up to ≈80 % cis isomers under favorable conditions. The photoswitching behavior of BPDBS‐crosslinked peptides was found to be highly dependent on the crosslinker attachment site. Upon UV irradiation (365 nm), significant decreases in α‐helix content were observed for peptides that were crosslinked with BPDBS through Cys residues at i,i+19, and i,i+21 positions. In contrast, large increases in α‐helix content were exhibited by i,i+11 crosslinked peptides. BPDBS thus constitutes a particularly bright and effective photoswitch for biomolecule photocontrol.     

Reverse atom transfer radical polymerization of methyl methacrylate in different solvents

The reverse atom transfer radical polymerization of methyl methacrylate was investigated in different solvents: xylene, N,N‐dimethylformamide, and pyridine. The polymerizations were uncontrolled, using 2,2′‐bipyridine as a ligand in xylene and pyridine because the catalyst (CuBr₂/2,2′‐bipyridine complex) had poor solubility in the xylene system. In the pyridine system, the solubility of the catalyst increased, but the solvent could complex with CuBr₂, which influenced the control of the polymerization. In the N,N‐dimethylformamide system, the catalyst could be dissolved in the solvent completely, but the ? N(CH₃)₂ group in N,N‐dimethylformamide could also complex with CuBr₂, so the polymerization could not be well controlled. The ligand of 4,4′‐di(5‐nonyl)‐2,2′‐bipyridine was also investigated in xylene; the introduction of the ? CH(C₄H₉)₂ group enabled the CuBr₂/4,4′‐di(5‐nonyl)‐2,2′‐bipyridine complex to easily dissolve in xylene, and the polymerizations were well controlled. The number‐average molecular weight increased linearly with the monomer conversion from 4280 to 14,700. During the whole polymerization, the polydispersities were quite low (1.07–1.10). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Synthesis of novel bipyridyl ligands and application in preparation of polyketone

In this article, novel 2,2′‐bipyridyl derivatives were synthesized and the excellent bipyridyl ligands were chosen as catalyst to apply in the copolymerization of carbon monoxide (CO) and styrene (ST) to prepare polyketone. 4,4′‐Dicarboxyl‐2,2′‐bipyridine(4,4′‐dcpy) was synthesized by use of synthesized 4,4′‐dimethyl‐2,2′‐bipyridine(4,4′‐dmpy). The products (4,4′‐dmpy and 4,4′‐dcpy) were characterized by melting point, NMR, IR, GC‐MS, and elemental analysis. The effects of different ligands and various reaction conditions incuding the usage of ligand, p‐toluenesulfonic acid, solvent, p‐benzoquinone, the CO pressure, and reaction temperature on catalytic activity of the copolymerization were investigated. The catalytic activity of 4,4′‐dmpy, 4,4′‐dcpy and 2,2′‐bipyridine were compared. The results showed that the addition of the electron‐donating substituent can enhance catalytic activity, with the sequence as follows: 4,4′‐ dimethyl‐2,2′‐bipyridine > 2,2′‐bipyridine > 4, 4′‐carboxy 2,2′‐ bipyridine. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci 000: 000–000, 2012     

Synthesis and luminescence properties of new blue‐light‐emitting polyconjugated poly{1,1′‐biphenyl‐4,4′‐diyl‐[1‐(4‐t‐butylphenyl)]vinylene} polymers and copolymers

Three new soluble polyconjugated polymers, all of which emitted blue light in photoluminescence and electroluminescence, were synthesized, and their luminescence properties were studied. The polymers were poly{1,1′‐biphenyl‐4,4′‐diyl‐[1‐(4‐t‐butylphenyl)]vinylene}, poly((9,9‐dioctylfluorene‐2,7‐diyl)‐alt‐{1,4‐phenylene‐[1‐(4‐t‐butylphenyl)vinylene‐1,4‐phenylene]}) [P(DOF‐PVP)], and poly([N‐(2‐ethyl) hexylcarbazole‐3,6‐diyl]‐alt‐{1,4‐phenylene‐[1‐(4‐t‐butylphenyl)]vinylene‐1,4‐phenylene}). The last two polymers had alternating sequences of the two structural units. Among the three polymers, P(DOF‐PVP) performed best in the light‐emitting diode devices of indium–tin oxide/poly(ethylenedioxythiophene) doped with poly(styrene sulfonate) (30 nm)/polymer (150 nm)/Li:Al (100 nm). This might have been correlated with the balance in and magnitude of the mobility of the charge carriers, that is, positive holes and electrons, and also the electronic structure, that is, highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels, of the polymers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 307–317, 2006