Antisar R. Hlil

Synthesis and thermal properties of poly(arylene ether ketone)s containing phthalazinone moieties

A series of novel poly(arylene ether ketone)s were synthesized from the reaction of hydroquinone and 4-(4-hydroxyphenyl)-2,3-phthalazin-1-one with 4,4′-difluorobenzophenone in N-cyclohexylpyrrolidinone containing anhydrous potassium carbonate. The polymers exhibited high glass transition temperatures together with excellent thermooxidative stability. The chain structure of these polymers was studied by means of differential scanning calorimetry (DSC), wide-angle X-ray diffraction techniques (WAXD), and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS). The experimental results indicated that these “as-made” copoly(aryleneketone)s containing hydroquinone moieties exhibited a block chain structure with segments which mainly consisted of hydroquinone and 4,4′-difluorobenzophenone. These chain segments resulted in crystallites in the polymers although they are thermodynamically unstable. The polymers showed thermal properties comparable to commercial PEEK, but the conditions for synthesis are much milder. The glass transition temperatures and solubilities of the copoly(arylene ketone)s tended to increase with increasing phthalazinone moiety content, while the crystallite melting points and crystallinity appeared to decrease.

New Materials and Procedures to Protect Metallic PEM Fuel Cell Bipolar Plates

High carbon content polymers have been synthesized and pyrolyzed between 600 and 850°C in inert ambient, during various pyrolysis times, to obtain freestanding carbon films with specific resistivities that can be as low as ∼0.01 Ω cm. One of these polymers (M2-48), with a low specific resistivity at low pyrolysis temperature and pyrolysis time, can be easily sprayed on stainless steel 316L, a possible material to be used for bipolar plates in polymer electrolyte membrane (PEM) fuel cells. The layer of M2-48 on SS316L is used as a first layer of a three-layer coating, which is able, after its pyrolysis at 750°C, to protect the stainless steel against corrosion in fuel cell tests. The second and third layers of the 70-100 μm thick protective coating are made of a commercial graphite spray and a top layer of M2-48, respectively.

Synthesis and characterization of a novel AlQ3-containing polymer

In this article, the synthesis of a tris(8-hydroxyquinoline)aluminum (AlQ3)-containing poly(arylene ether) (4) is reported. The presence of AlQ3 pendants in polymer 4 is confirmed by NMR, ultraviolet–visible, photoluminescence, and gel permeation chromatography analyses. This is the first report of the attachment of AlQ3 complexes as side chains to a polymer. Polymer 4 has a glass-transition temperature of 217.8 °C and is thermally stable with a 5% weight-loss temperature greater than 500 °C under nitrogen, as determined by differential scanning calorimetry and thermogravimetric analyses, respectively. Polymer 4 is quite soluble in common organic solvents, such as tetrahydrofuran, N,N-dimethylacetamide, and CHCl3. A composite that is 80 wt % polymer 4 and 20 wt % AlQ3 forms a transparent and tough film when cast from its chloroform solution. The application of this AlQ3-containing polymer in light-emitting diodes is under investigation.

Poly(arylene ether)s, poly(arylene thioether)s, and poly(arylene sulfone)s derived from a dihydroxy(imidoarylene) monomer

Novel poly(arylene ether)s, poly(arylene thioether)s, and poly(arylene sulfone)s were synthesized from the dihydroxy(imidoarylene) monomer 1. The syntheses of poly(arylene ether)s were carried out in DMAc in the presence of anhydrous K2CO3 by a nucleophilic substitution reaction between the bisphenol and activated difluoro compounds. Poly(arylene thioether)s were synthesized according to the recently discovered one-pot polymerization reaction between a bis(N,N′-dimethyl-S-carbamate) and activated difluoro compounds in the presence of a mixture of Cs2CO3 and CaCO3. The bis(N,N′-dimethyl-S-carbamate) 3 was synthesized by the thermal rearrangement reaction of bis(N,N′-dimethylthiocarbamate) 2, which was synthesized from 1 by a phase-transfer catalyzed reaction. The poly(arylene thioether)s were further oxidized to form poly(arylene sulfone)s, which would be very difficult, if not impossible, to synthesize by other methods. All of the polymers described have extremely high Tgs and thermal stability as determined from DSC and TGA analysis. Poly(arylene sulfone)s have the highest Tgs and they are in the range of 298–361°C.

Synthesis of poly(arylene ether)s containing hole-transport moieties from an isocyanate masked bisphenol

The design and synthesis of novel charge (hole- or electron-) transport materials have been the focus of much research in recent years because of their wide variety of applications. In this study, three high molecular weight poly(arylene ether)s, 6a–c, containing naphthyl-substituted benzidine moieties have been synthesized from carbamates derived from bisphenols. After masking with n-propyl isocyanate, the carbamate is stable, can be readily purified by recrystallization from toluene, and can be polymerized directly with difluoro compounds under mild conditions. The resulting polymers possess high glass-transition temperatures, excellent thermal stability, and good film-forming properties. In comparison, the poly(arylene ether)s 6a′–c′, synthesized from unprotected bisphenol, have lower molecular weights and wider polydispersity and contain some brown impurities. Preliminary experiments show that both 6a and 6a′ can function well as hole-transport materials in light-emitting diodes.

Poly(arylene ether)s from new biphenols containing imidoarylene and dicyanoarylene moieties

Novel poly(arylene ether)s were synthesized from new biphenol monomers 14–161 containing imido- or dicyanoarylene groups. The syntheses of these polymers were carried out in tetramethylene sulfone in the presence of anhydrous K2CO3, by a nucleophilic substitution condensation between the biphenol and activated difluoro compounds to give high molecular weight polymers. All the polymers have high Tg s and good thermal stability as determined from DSC and TGA analysis. Inherent viscosities of these polymers are in the range of 0.33–0.63 dL/g. They are amorphous and readily soluble in NMP, DMF, and DMSO. The glass-transition temperatures of the polymers range from 248–295 °C.

Blue double layer devices obtained by spin-coating

Abstract Double spin-coated electroluminescent (EL) devices have been prepared by combining a blue EL arylamine-based hole transport polymer (STPD-QP) in the first spin-coated layer with a blue EL oxadiazole-based electron transport polymer (SP-OX) in the second layer. The luminance and efficiency of these devices are improved by adding PBD, a low molecular weight electron transport oxadiazole derivative, as a solute in the SP-OX layer. Doing so, maximum luminance of ∼1500 cd/m 2 and quantum efficiencies up to 0.5% are obtained. Similar luminances cannot be reached by using only solid solutions of PBD in A435, a rather insulating host polymer.

Synthesis and Properties of Carbazole-containing Copolymers from Bis[3-(4-fluorobenzoyl)carbazole] Methane

A novel difluoride containing carbazole groups was designed. Two series of polycarbazoles based on the novel monomer were synthesized via C-N coupling reactions with either 4,4′-biphenol or bisphenol A. Copolymers were obtained with 4,4′-difluorobenzophenone or bis(4-fluorophenyl) sulfone as comonomer. The solubilities of the poly(carbazole ketones)s were poor, but the poly(carbazaole sulfones)s all dissolved in NMP, DMSO and DMAC. Tough films of poly(carbazole sulfones)s could be easily cast from NMP solutions. The viscosities of poly(carbazole sulfones)s were 0.72 ∼ 0.90 dL/g. The Tgs of polymers ranged from 162.4°C to 258.9°C. The temperatures of 5% wt loss ranged from 460°C to 509°C. UV-Vis absorptions and blue light emissions properties are also presented.

Polycarbazole Copolymers from 3-(4-Fluorobenzoyl)carbazole and 4,4′-Biphenol via Combined C-N and C-O Coupling Reactions with Activated Difluorides

3-(4-Fluorobenzoyl)carbazole was synthesized by a Friedel-Crafts reaction of carbazole with 4-fluorobenzoylchloride. 1H-NMR and MALDI-TOF MS confirmed the structure and the purity. Copolymers of these NH/OH-containing monomers were prepared with 4, 4′-biphenol and bis(4-fluorophenyl)sulfone as comonomers by combined C-O and C-N coupling reactions with activated difluorides. These copolymers were soluble in N-methylpyrrolidinone (NMP), dimethylsulfoxide (DMSO), N,N-dimethylacetamide (DMAc) and dimethylformamide (DMF). The inherent viscosities of the copolymers in NMP solutions at 30°C were all around 0.8 dL/g. They could be easily cast into tough films from NMP solutions. The copolymers exhibited Tgs ranging from 238°C to 282°C. Thermal stabilities by TGA showed no weight loss below 400°C and the temperatures of 5% weight loss ranged from 535°C to 558°C. The homopolymer of 3-(4-fluorobenzoyl)carbazole was insoluble in common solvents and had a Tg of 332°C, and temperature of 5% weight loss of 560°C. UV-VIS absorption and fluorescence of the polymers are also presented.

BLUE LIGHT EMITTING COPOLY-(ARYLENE ETHER)S CONTAINING A 3,6- DIALKOXYPHTHALIMIDE GROUP

ABSTRACT Four new bisphenols containing 3,6-dialkoxyphthalimide moieties were prepared in high yields. They were copolymerized with BPA or 2,5-bis(4-hydroxyphenyl)oxadiazole by reaction with decafluorobiphenyl and with NaH as base to give novel copoly(arylene ether)s. The resulting copolymers have glass-transition temperatures (Tg) ranging from 153 to 235°C and very good thermal stabilities with 5% wt loss temperatures (TGA) ranging from 378 to 499°C. These polymers show strong blue light emission in wavelengths ranging from 420 to 430 nm, while their UV absorption peaks vary from 368 to 383 nm. They have excellent solubility in common organic solvents.