Synthesis and properties of novel fluorinated poly(arylene ether)s

Dibromomethylene‐containing monomer with a tetrafluorobenzene central unit was synthesized using 2,3,5,6‐tetrafluoro‐1,4‐bis(4‐methylphenoxy)benzene as a starting material. This approach enabled preparation of several fluorinated poly(arylene ether)s containing isomeric fragments, with or without allyl or acetyl side groups, which were prepared by interaction of the synthesized tetrafluorobenzene‐based monomer with various types of hydroxyl‐substituted diphenyl ethers. The structure of the synthesized compounds was determined using Fourier transform infrared, ¹H NMR and ¹⁹ F NMR spectroscopy techniques. Most of the resulting polyethers were soluble in chlorinated, ether‐type or polar amide solvents. The molecular weight, mechanical and thermal properties of the synthesized fluorinated poly(arylene ether)s were studied depending on the inherent isomery of macromolecular chains and the nature of functional groups. Some ways of functionalization of the prepared fluorinated polyethers with epoxy and triethoxysilyl groups were proposed. © 2015 Society of Chemical Industry     

Novel poly(arylene ether)s containing multi-substituted pentaphenylene moiety

Three novel 2-trifluoromethyl-activated bisfluoro monomers have been synthesized successfully using a Suzuki-coupling reaction of 4-fluoro-3-trifluoromethyl phenyl boronic acid with 4,4′-dibromo-p-terphenyls with varied phenyl substitution on the middle phenylene ring. Three monomers were converted to a series of phenyl substituted poly(arylene ether)s by nucleophilic displacement of the fluorine atoms on the terminal benzene ring with several bisphenols. The polymers obtained by displacement of the fluorine atoms exhibit weight-average molecular weight up to 2.25 × 10⁵ g/mol in GPC. Thermal analysis studies indicated that these polymers did not show melting endotherms but did show ultrahigh T_g values up to 334 °C in DSC and outstanding thermal stability up to 671 °C for 5% weight loss in TGA under nitrogen atmosphere. The polymers are soluble in a wide range of organic solvents: THF, CHCl₃, NMP, DMAc, DMF, toluene, etc., and are insoluble in DMSO and acetone at room temperature. Transparent and flexible films were easily prepared by solution casting from chloroform solution of each of the polymers. The UV absorption spectra of thin films showed no absorption in the visible light region of the spectrum, suggesting a good application to optical transparent materials in the visible light region of the spectrum.     

Synthesis and characterization of low-birefringent crosslinkable fluorinated poly(arylene ether sulfide)s containing pendant phenyl moiety

Fluorinated poly(arylene ether sulfide) (FPAESI) and ethynyl-terminated fluorinated poly(arylene ether sulfide) (E-FPAESI) were synthesized via step-growth polymerization from prepared dihydroxy monomer and pentafluorophenylsulfide, then E-FPAESI was followed by a reaction with 3-ethynylphenol. The number-average molecular weights and polydispersities of FPAESI and E-FPAESI were in the range of 12,000-26,000 and 1.75-3.18, respectively. The glass transition temperatures of the polymers varied from 138 to 178 °C depending on the molecular weight of the polymer used and were changed to the range of 191-245 °C after curing. The FPAESIs and E-FPAESIs exhibited high thermal stability up to 445-450 °C and 457-462 °C, respectively. The refractive index and birefringence of spin-coated polymer films were determined by the prism-coupling method. The refractive indices and birefringences of the films were in the range of 1.5849-1.5880 and 0.0014-0.0035 at a 1550 nm wavelength, respectively. The effect of E-FPAESI structure on the birefringence is compared with various reported poly(arylene ether sulfide)s.     

Hyperbranched poly(arylene ether phosphine oxide)s

Summary New AB₂ and A₂B monomers, bis(4-fluorophenyl)-4'-hydroxyphenylphosphine oxide and bis(4-hydroxyphenyl)-4'-fluorophenyl-phosphine oxide were prepared and converted to corresponding hyperbranched poly(arylene ether phosphineoxide)s with hydroxyphenyl and fluorophenyl end functional groups. While the dihydroxy monomer gave a low molecular weight polymer, the difluoro monomer produced a high molecular weight hyperbranched polymer. The glass transition temperature of the obtained polymers was 266°C and 230°C, and 5% weight loss temperature was 491 °C and 391 °C, respectively. The fluorophenyl-terminated hyperbranched polymer was soluble in CHCl₃, but the hydroxyphenyl-terminated polymer was not soluble in CHCl3 even though it has lower molecular weight than the fluorophenyl-terminated polymer, indicating that properties of the hyperbranched polymers markedly depend on end functional groups as well as their molecular weight. Received: 23 August 2000/Revised version: 19 October 2000/Accepted: 31 October 2000     

Synthesis and characterization of sulfonated fluorene-containing poly(arylene ether ketone) for high temperature proton exchange membrane

A novel fluorene-containing poly(arylene ether ketone) were synthesized followed by sulfonating into a series of sulfonated fluorene-containing poly(arylene ether ketone)s using chlorosulfonic acid. The sulfonated polymers were thereafter cast into membranes from their solutions. The properties of the ionic exchange capacity, sulfonation degree, water-uptake, mechanical properties, thermal and oxidative stabilities as well as proton conductivities of the membranes were fully investigated. It was found that their proton conductivities increased continuously with increasing testing temperature up to 130 °C at 100% relative humidity. The membrane exhibited a higher proton conductivity and other comprehensive properties for proton exchange membrane than Nafion-117 at 130 °C under same testing conditions.     

Phosphonated poly(arylene ether)s as potential high temperature proton conducting materials

The preparation and characterization of new phosphonated polymeric ionomers based on a fully aromatic poly(arylene ether) backbone with applications as proton exchange membranes for fuel cell is reported. The high-molecular-weight polymers were obtained by the polycondensation of the phosphonated monomers with decafluorobiphenyl in high yields with inherent viscosities up to 0.58 dL g⁻¹. The hydrolysis of the phosphonated ester into phosphonic acid groups was carried out quantitatively under acidic conditions. The polymers were studied by TGA after hydrolysis and showed10% weight loss above 430 °C. Membranes with total ion-exchange capacities above 6 meq/g showed proton conductivities of approximately92 mS/cm at 25 °C and 100% relative humidity increasing to ca.150 mS/cm at 140 °C. Their conductivity under dry condition showed values over 2 mS/cm at 120 °C which upon doping with phosphoric acid jumped to nearly 100 mS/cm.     

Synthesis and Characterization of New Copoly(arylene ether)s Containing Naphthalene or Naphthalene/1,3,4-Oxadiazole Units

Summary Series of new copoly(arylene ether)s containing naphthalene or naphthalene/1,3,4-oxadiazole units have been obtained by polycondensation in solution starting from the following systems of monomers: 1,5 or 2,6-bis(4-fluorobenzenesulfonyl) naphthalene / 2,6-bis(4-fluorobenzoyl)naphthalene, 1,5 or 2,6-bis(4-fluorobenzen sulfonyl)naphthalene / 2,2-(oxydi-4,1-phenylene)bis[5-(4-fluorophenyl)-1,3,4- oxadiazole] and 2,6 bis-(4 fluorobenzoyl)naphthalene/2,2-(oxydi-4,1-phenylene)bis [5-(4-fluorophenyl)- 1,3,4-0xadiazole]. Hydroquinone and 4,4dihydroxy benzophenone have been used as aromatic dihydroxy compounds. The copolymers, obtained in quantitative yields, possessed inherent viscosities in the range 0.28-0.58 dl g^-1, had good thermal stability (10% weight loss temperatures were above 460°C both in nitrogen and air) and high glass transition temperatures (in the range 190-210°C). They have been characterized by infrared analyses, GPC and wide-angle X-ray diffraction. The copolymer property-structure relationships were studied and the properties have been compared with those of the corresponding homopolymers.     

Fluorinated poly(arylene ether sulfone)s for polymeric optical waveguide devices

Pentafluorophenyl sulfone was prepared by oxidation of pentafluorophenyl sulfide. Ethynyl terminated fluorinated poly(arylene ether sulfone) (EFPAESO) was synthesized via nucleophilic aromatic substitution from 4,4′-(hexafluoroisopropylidene) diphenol or 4,4′-(trifluoromethylphenylisopropylidene) diphenol with an excess of pentafluorophenyl sulfone, followed by reaction with 3-ethylnylphenol. The molecular weights (M_ns) of the polymers determined by GPC with polystyrene standard were in the range of 6,400-17,200 and polydispersities (M_w/M_ns) were in the range of 2.25-3.19. This EFPAESO showed very high thermal stability up to 479 °C for 5% weight loss in TGA in air. T_g of the polymer was changed from 148 to 196 °C after curing. The cured films showed good chemical resistance and high thermal-stability. At 1550 nm wavelength, the refractive indices of the copolymer films were in the range of 1.5037-1.5504 and birefringences were in the range of 0.0021-0.0025. The optical loss for EFPAESO was less than 0.37 dB/cm at 1550 nm wavelength.     

Poly(arylene ether sulfone) multi-block copolymers bearing perfluoroalkylsulfonic acid groups

Poly(arylene ether sulfone) (PAES) multi-block copolymers bearing perfluoroalkylsulfonic acid moieties were prepared from hydrophilic and hydrophobic prepolymers. The latter were synthesized by reaction of N,N-diisopropylethylammonium 2,2-bis(p-hydroxyphenyl)pentafluoropropanesulfonate (HPPS) with bis-(4-fluorophenyl) sulfone (FPS), and biphenol (BP) with FPS, respectively. Prepolymers and multi-block copolymers were prepared at 180 °C in N,N-dimethylacetamide in the presence of K₂CO₃. The prepolymers were reacted overnight; the multi-block copolymers were reacted only 80 min to minimize transetherification. Prepolymers and multi-block copolymers were characterized using ¹H and ¹³C NMR. ¹⁹F NMR provided molecular weight of hydrophilic prepolymers bearing aryl fluoride end groups. GPC was used to characterize the multi-block copolymers. Copolymer block lengths were determined by quantifying ¹³C NMR peak areas of quaternary carbon atoms adjacent to sulfur in FPS moieties. Hydrophilic and hydrophobic block lengths were in the range 9.4-23.4 and 4.4-11.8 repeating units, respectively. AFM showed phase separation for all block lengths. Conductivity at 80 °C and 100% relative humidity ranged from 6.2 to 34.3 mS/cm, with the best value obtained for hydrophilic/hydrophobic block lengths of 13.3/6.0.     

Thermal analysis of disulfonated poly(arylene ether sulfone) plasticized with poly(ethylene glycol) for membrane formation

One route to melt processing of high glass transition temperature polyelectrolytes, such as disulfonated poly(arylene ether sulfone) (BPS), involves mixing a plasticizer with the polymer. In this study, poly(ethylene glycol) (PEG) was used as a plasticizer for BPS. BPS and PEG are miscible, and the effect of PEG molecular weight (in the range of 200–600 g/mol) and concentration on the T_g of BPS/PEG blends was investigated. As PEG molecular weight decreases and concentration increases, the blend T_g is depressed significantly. Based on isothermal holds in a rheometer at various temperatures and times, the PEG materials considered were thermally stable up to 220 °C for 10 min in air or 250 °C for at least 10 min under a nitrogen atmosphere, which is long enough to permit melt extrusion of such materials.     

Synthesis of dendritic poly(arylene ether)s from a linear polymer core

Three generations of dendritic poly(arylene ether)s with terminal 4-fluorophenylthio- or 4-fluorophenylsulfonyl groups have been synthesized. A new relatively high molecular weight bisphenol containing two pendent 4-fluorophenylthio groups was converted to a poly(arylene ether sulfone) to act as the dendritic core. A divergent approach with an activation/condensation sequence was used. The pendent 4-fluorophenylthio groups in the base polymer were oxidized with H₂O₂ in formic acid to give 4-fluorophenylsulfonyl groups in which the fluoride groups are then activated toward nucleophilic displacement reactions. The condensation step involved the reaction of a phenol containing two pendent 4-fluorophenylthio groups with the activated core polymer in the presence of Cs₂CO₃. Reiteration of these steps gave the subsequent generations. The polymers have high thermal stabilities by TGA analysis (5% weight loss>500 °C).     

Cross-linkable highly halogenated poly(arylene ether ketone/sulfone)s with tunable refractive index: Synthesis, characterization and optical properties

A series of novel cross-linkable, highly halogenated poly(arylene ether ketone)s (HPAEKs) and poly(arylene ether sulfone)s (HPAESs) with different bromine contents have been designed and prepared by polycondensation reactions for use as optical waveguide materials. The method used for their preparation involved reacting decafluorodiphenyl ketone/sulfone (DFPK/DFPS) with a mixture of 4,4′-isopropylidene bis(2,6-dibromophenol) (4Br-BPA), 4,4′-(hexafluoroisopropylidene)diphenol (6F-BPA), and 1,1-bis(4-hydroxyphenyl)ethyl-1-phenyl-2,3,5,6-tetrafluorostyrol ether (BHPFS). The feed ratio of 4Br-BPA to the total bisphenols varied from 0 to 80 mol.%, while that of BHPFS remained at 20% for all polymers. The resulting polymers have excellent solubility in most common organic solvents such as tetrahydrofuran, cyclohexanone and N,N-dimethylacetamide (DMAc) and can be easily cast into optical-quality thin films. A high glass transition temperature in the range of 164-206 °C was found for these polymers, which could be further increased by about 20 °C upon thermal or photochemical cross-linking. Slab and channel waveguides have been prepared from these polymers. All of them exhibited low optical loss (0.4-0.6 dB/cm) at the telecommunication wavelength of 1550 nm. Due to the relatively higher polarizability of the C-Br bond than that of the C-H bond, an increase in the refractive index was observed as the bromine content in the polymers increased. Consequently, the refractive index of HPAEKs and HPAESs can be readily adjusted within a wide range from 1.51 to 1.57 by simply changing the ratio of the bromine-containing bisphenol in the feed. This variability, along with the excellent cross-linking capability, allows these polymers to be used as both the core and the cladding materials for the waveguide device fabrication and provides a greater flexibility in the design of device structures.     

Synthesis of highly sulfonated poly(arylene ether sulfone)s with sulfonated triptycene pendants for proton exchange membranes

A series of poly(aryl ether sulfone)s containing triptycene groups PES-x-TPD (x refers to molar percentage of TPD) were firstly synthesized through nucleophilic aromatic substitution polycondensation by using 2,5-triptycenediol (TPD), bis(4-hydroxyphenyl) sulfone (BHPS) and 4,4′-difluorodiphenyl sulfone (DFDPS). The sulfonation of copolymers was conducted at room temperature by using a mild sulfonating reagent (98% H₂SO₄), and the degree of sulfonation was readily and accurately controlled by adjusting the ratio of TPD and BHPS. The structures of PES-x-TPD and SPES-x-TPD were characterized by IR, ¹H NMR and ¹³C NMR spectra. These ionomers generally showed high thermal stability and mechanical strength at low humidity regardless of high IEC value. Meanwhile, it is noteworthy that these novel SPES-x-TPD membranes with high IEC value achieved high proton conductivity in a wide range of humidity at 80 °C. For example, SPES-60-TPD with the highest IEC value 2.86 mmol/g displays the conductivity of 2.5 × 10⁻¹ S/cm which is much higher than that of the perfluorinated Nafion membrane (1.1 × 10⁻¹ S/cm) at 80 °C and 94% RH. At 80 °C and 34% RH, SPES-60-TPD displays the conductivity of 4.5 × 10⁻³ S/cm which is also higher than that of the Nafion membrane (3.0 × 10⁻³ S/cm). Microscopic analyses revealed that well-de?ned phase separated structures and uniform ionic pathway was formed for SPES-45-TPD membrane with the IEC of 2.29 mmol/g. Moreover, a H₂/O₂ fuel cell using the SPES-55-TPD (IEC = 2.68 mmol/g) also showed better performance than that of Nafion 117 at 40 °C and 30% RH.     

Synthesis, characterization, and crosslinking of soluble cyano-containing poly(arylene ether)s bearing phthalazinone moiety

A novel series of phthalazinone-based poly(arylene ether nitrile)s bearing terminal cyano groups via N-C linkages (PPEN-DCs) were synthesized by a simple solution polycondensation of 4-(4-hydroxylphenyl)(2H)-phthalazin-1-one (HPPZ) with calculated 2,6-difluorobenzonitrile (DFBN), followed by the termination of 4-chlorobenzonitrile (CBN). The M_ns of oligomeric PPEN-DCs, which are in the range of 1600-6200, can be well-controlled by adjusting reactant ratio. The incorporation of phthalazinone into the polymer chain results in an improvement in the solubility and glass transition temperatures (T_gs). The amorphous PPEN-DCs were thermally crosslinked to afford insoluble products in the presence of terephthalonitrile and zinc chloride. The pendant cyano groups in the polymer chain hardly undergo any crosslinking or cyclization, while the terminal cyano groups with nitrogen-bridged phthalazinone in the para-substitution are much more reactive in s-triazine forming reaction and effectively promote certain crosslinking under normal pressure. T_gs of the oligomers, which range from 245 to 269 °C, could be further increased at least by 94 °C upon thermal curing. The crosslinked samples exhibit excellent thermal stability and absorb less than 2.7 wt% water after exposure to an aqueous environment for extended periods. This kind of cyano-terminated poly(arylene ether nitrile)s may be a good candidate as matrix resins for high-performance polymeric materials.     

New poly(arylene ether)s containing phthalimidine group in the main chain

Five new poly(arylene ether)s containing phthalimidine group in the main chain and pendent trifluoromethyl group have been prepared by the reaction of 4,4′‐(bis‐4‐fluoro‐3‐trifluoromethylphenyl)benzene (BTF) with bisphenols. Different molar ratios of N‐phenyl‐3,3‐bis(4‐hydroxyphenyl)phthalimidine (PA) and 4,4′‐isopropylidenediphenol (BPA) have been used to generate different copolymers. The polymers obtained by step growth polymerization exhibited weight‐average molecular weight upto 134,000 g/mol with a polydispersity index of 2.1–2.4. The homopolymer from BTF and PA showed very high glass transition temperature of 258°C and outstanding thermal stability upto 536°C for 5% weight loss under nitrogen. The polymers were soluble in a wide range of organic solvents. Transparent thin films of these polymers exhibited tensile strengths upto 65 MPa and elongation at break upto 45% depending on the exact repeat unit structures. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Zirconium phosphate sulfonated poly (fluorinated arylene ether)s composite membranes for PEMFCs at 100-140 °C

Organic-inorganic hybrid composite membranes have been prepared and evaluated for polymer electrolyte membrane fuel cells (PEMFCs) at 100-140 °C. A series of synthesized poly (fluorinated arylene ether)s was sulfonated by fuming sulfuric acid (20% SO₃). The zirconium phosphate composite membrane was prepared by soaking the sulfonated poly (fluorinated arylene ether)s stepwise in 1 M zirconyl chloride solution and 1 M phosphoric acid solution. The chemical, thermal, and electrochemical properties of the composite membrane were investigated by thermogravimetric analysis (TGA), field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV), and unit cell test. The cell performance of the zirconium phosphate sulfonated poly (fluorinated arylene ether)s composite membrane was superior to that of the starting membrane at intermediate temperature, 100-140 °C. And the cell performance with composite membrane indicated stable behavior during experimentation when operating temperature maintained at 120 °C, whereas sulfonated poly (fluorinated arylene ether)s membrane was irreversible degradation under the same condition.     

Comparison of the water uptake and swelling between sulfonated poly(phthalazinone ether ketone ketone)s and sulfonated poly(arylene ether ketone ketone)s

Summary Sulfonated poly(phthalazinone ether ketone ketone)s (sPPEKK) and sulfonated poly(arylene ether ketone ketone sulfone)s (sPAEKK) were successfully synthesized by direct polycondensation. The water uptake and swelling of sPPEKK are much less compared with those of sPAEKK, especially in high temperature, which result from the powerful intermolecular hydrogen bonds of sPAEKK, confirmed by variable temperature IR spectra. The maximum operation temperature of proton exchange membranes made of sPPEKK is higher than 80 °C, improving the property of resistance to swelling.     

Synthesis and characterization of organo‐soluble poly(ether ether ketone)s and poly(ether ether ketone ketone)s containing pendant pentadecyl chains

Poly(ether ether ketone)s and poly(ether ether ketone ketone)s containing pendant pentadecyl chains were synthesized by polycondensation of each of the two bisphenol monomers viz, 1,1,1‐[bis(4‐hydroxyphenyl)‐4′‐pentadecylphenyl]ethane and 1,1‐bis(4‐hydroxyphenyl)‐3‐pentadecyl cyclohexane with activated aromatic dihalides namely, 4,4′‐difluorobenzophenone, and 1,3‐bis(4‐fluorobenzoyl)benzene in a solvent mixture of N,N‐dimethylacetamide and toluene, in the presence of anhydrous potassium carbonate. Polymers were isolated as white fibrous materials with inherent viscosities and number average molecular weights in the range 0.70–1.27 dL g^?1 and 76,620–1,36,720, respectively. Poly(ether ether ketone)s and poly(ether ether ketone ketone)s were found to be soluble at room temperature in organic solvents such as chloroform, dichloromethane, tetrahydrofuran, and pyridine and could be cast into tough, transparent, and flexible films from their solutions in chloroform. Wide angle X‐ray diffraction patterns exhibited a broad halo at around 2θ = ～ 19° indicating that the polymers containing pentadecyl chains were amorphous in nature. In the small‐angle region, diffuse reflections of a typically layered structures resulting from the packing of pentadecyl side chains were observed. The temperature at 10% weight loss, obtained from TG curves, for poly(ether ether ketone)s and poly(ether ether ketone ketone)s were in the range 416–459°C, indicating their good thermal stability. A substantial drop in glass transition temperatures (68–78°C) was observed for poly(ether ether ketone)s and poly(ether ether ketone ketone)s due to “internal plasticization” effect of flexible pendant pentadecyl chains. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Poly(aryl ether sulfide)s by sulfide-activated nucleophilic aromatic substitution polymerization

Poly(aryl ether sulfide)s have been produced by nucleophilic aromatic substitution with phenoxide nucleophiles bisphenol A and bisphenol AF, and the activated arylfluorides bis(4-fluorophenyl)sulfide and 2,7-difluorothianthrene. The resulting polymers are thermally stable, amorphous materials that have been characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and gel permeation chromatography (GPC). Moderate molecular weights have been achieved, representative of greater than 98% conversion of arylfluorides. The poly(aryl ether thianthrene)s are flame resistant and self extinguish within 0.2 s upon removal from a flame source. TGA of the poly(aryl ether thianthrene)s in an inert atmosphere result in a char yield greater than 50% at 750 °C. The flame resistant properties are more effectively modeled by TGA in an inert atmosphere as compared to TGA in an air atmosphere. The poly(aryl ether thianthrene)s are found to have high refractive index values, 1.61-1.70, depending on wavelength and bisphenol composition.     

2,2 bis (4-ethynylphenyl) hexafluoropropane

Summary The 2,2 bis(4-ethynylphenyl)hexafluoropropane is prepared via an original synthesis's process using a substitution of 2,2 bis(4-triflatephenyl) hexafluoropropane by trimethylsilyl acetylene. In this process ZnO is used to remove the triflate anion formed during the reaction.This diacetylenic compound melts at 37–38°C, exhibits an onset of polymerization at 120°C. After thermal treatment at 250°C, the obtained network shows a softening point at 300°C. This network remains stable in air up to 435°C.