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     

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     

Kinetics of isothermal and nonisothermal crystallization of nylon 1313

The crystallization process of a new polyamide, nylon 1313, from the melt has been thoroughly investigated under isothermal and nonisothermal conditions. During isothermal crystallization, relative crystallinity develops in accordance with the Avrami equation with the exponent n ≈ 2 based on DSC analysis. Under nonisothermal conditions, several different analysis methods were used to elucidate the crystallization process. The Avrami exponent n is greater in the isothermal crystallization process, indicating that the mode of nucleation and the growth of the nonisothermal crystallization for nylon 1313 are more complicated, and that the nucleation mode might include both homogeneous and heterogeneous nucleation simultaneously. The calculated activation energy is 214.25 kJ/mol for isothermal crystallization by Arrhenius form and 135.1 kJ/mol for nonisothermal crystallization by Kissinger method, respectively. In addition, the crystallization ability of nylon 1313 was assessed by using the kinetic crystallizability parameters G. Based on this parameter, the crystallizability of many different polymers was compared theoretically. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1415–1422, 2007     

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.     

Synthesis and characterization of novel (sulfonated) poly(arylene ether)s with pendent trifluoromethyl groups

This paper reports the synthesis of four different trifluoromethyl-substituted poly(arylene ether)s on the basis of 2,2-bis(4-hydroxyphenyl)hexafluoropropane (bisphenol AF) and various difluoro- or dinitrobiphenyl or terphenyl monomers in the course of a step-growth polycondensation. Besides a comparison between the polymerisability of the different monomer combinations, a main focus of this work lies on the NMR characterization of these poly(arylene ether)s. Poly(arylene ether)s with sufficiently high number average molecular weights were sulfonated by fuming sulfuric acid or chlorosulfonic acid and investigated in terms of membrane properties relevant for fuel cell applications.     

Adhesion property of sulfonated poly(arylene ether sulfone)s

Sulfonated poly(arylene ether sulfone)s (S‐PESs) were synthesized from sulfonated 4,4′‐dichlorodiphenylsulfone (S‐DCDPS), 4,4′‐dichlorodiphenylsulfone (DCDPS), and 4,4′‐biphenol through variations in the molar ratio of S‐DCDPS to DCDPS from 10/90 to 40/60. The S‐PES sodium form was characterized with Fourier transform infrared, ¹H‐NMR, thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis, and the intrinsic viscosity and solubility were also evaluated. The sodium form was then subjected to acidification by immersion in 1.5M HCl for 24 h at room temperature, which was followed by washing with deionized water. The S‐PES adhesive properties were measured with single laboratory shear samples with aluminum alloys, and the failure mode was investigated. The synthesized S‐PESs exhibited increased glass‐transition temperatures with increased S‐DCDPS/DCDPS ratios; their acid forms provided much lower glass‐transition temperatures than their sodium forms. In addition, the S‐PES sodium form exhibited a high intrinsic viscosity, which indicated a high molecular weight. The S‐PES acid form exhibited an adhesion strength similar to that of the sodium form, and the single‐lap‐shear strength increased with 10% S‐PES and then decreased with 20, 30, and 40% S‐PES. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1211–1218, 2004     

Evaluation of nonisothermal crystallization kinetic models for linear poly(phenylene sulfide)

The nonisothermal crystallization kinetics of linear Poly(phenylene sulfide) (PPS) was studied with differential scanning calorimetry. Ozawa theory, Jeziorny model, and Mo equation were applied to describe the crystallization kinetics and to determine the crystallization parameters and mechanism of the linear PPS resin. The crystallization activation energies were also calculated using Kissinger formula and Flynn‐Wall‐Ozawa equation, respectively. According to the Ozawa model, it is found that instantaneous nucleation takes place during crystallization of PPS; the Ozawa exponent m is 3 in initial stage of crystallization; as the crystallization temperature decreases, the value of m reduces, and the growth rate of crystal almost keeps a constant. The Avrami exponent n obtained from Jeziorny model fluctuate around 1.84. Based on the Jeziorny model, the crystallization rate increases with increasing the cooling rate, but it does not change any longer when the cooling rate rise to a certain value. Mo equation also exhibits great advantages in treating the nonisothermal crystallization kinetics of PPS. The activation energy E of nonisothermal crystallization process of PPS is calculated to be −162.73 kJ/mol by the Kissinger formula, and the mean value of E determined by Flynn‐Wall‐Ozawa equation is −152.40 kJ/mol. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis and characterization of flame resistant poly(arylene ether)s

Hydrolytically stable phosphorus-containing monomers, such as 4,4′-bis(fluorophenyl)methylphosphine oxide (BFPMPO), 4,4′-bis(hydroxyphenyl)methylphosphine oxide (BOHPMPO), and 4,4-bis(hydroxyphenyl)phenylphosphine oxide (BOHPPO), were synthesized and used in nucleophilic aromatic substitution poly-condensation to prepare poly(arylene ether phosphine oxide) engineering thermoplastics. The synthesis and characterization of these novel polymers are described. It was determined that by incorporating the phosphine oxide moiety into the polymer backbone, certain properties of the resulting poly(arylene ether) were substantially improved, such as an increase in T_g, thermal stability in air, modulus, and char yield compared with control poly(arylene ether sulfone)s. The high char yields obtained for these polymers in air along with observed intumescence indicates that these materials have improved fire resistance. Preliminary cone calorimetry measurements support this conclusion.     

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.     

Investigation on the crystallization behavior of poly(ether ether ketone)/poly(phenylene sulfide) blends

The morphology of nonisothermally crystallized poly(phenylene sulfide) (PPS) and its blend with poly (ether ether ketone) (PEEK) have been observed by polarized optical microscope (POM) equipped with a hot stage. The nonisothermal crystallization behavior of PPS and PEEK/PPS blend has also been investigated by differential scanning calorimetry (DSC). The maximum crystallization temperature for PEEK/PPS blend is about 15°C higher than that of neat PPS, and the crystallization rate, characterized by half crystallization time, of the PEEK/PPS blend is also higher than that of the neat PPS. These results indicate that the PEEK acts as an effective nucleation agent and greatly accelerates the crystallization rate of PPS. The Ozawa model was used to analyze the nonisothermal crystallization kinetics of PPS and its blends. The Avrami exponent values of neat PPS are higher than that of its blend, which shows that the presence of PEEK changed the nucleation type of PPS from homogeneous nucleation to heterogeneous nucleation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Poly(arylene ether sulfones) and poly(arylene ether ketones) derived from dibenzofuran

Summary New polyarylene ether ketones and polyarylene ether sulfones were prepared by polycondensation of various bisphenols with two new dihalide monomers including dibenzofuran structure, respectively 3,6 bis (4-fluorophenylcarbonyl) dibenzofuran and 3,6 bis (4-fluorophenylsulfonyl) dibenzofuran. Most of these thermoplastic polyethers are soluble in NMP and in chlorinated soluents. They exhibit Tgs up to 234°C for the polyetherketones and up to 262°C for the polysulfones, so over 50°C higher than the Tgs of classical available polyethers.     

Synthesis and characterization of novel soluble cardo poly(arylene ether ketone)s containing xanthene structures

9,9‐Bis(4‐hydroxyphenyl)xanthene (BHPX), a bisphenol monomer, was synthesized in 82% yield from xanthenone in a one‐pot, two‐step synthetic procedure. Four novel aromatic poly(ether ketone)s (PEKs) based on BHPX were prepared via a nucleophilic aromatic substitution polycondensation with four difluorinated aromatic ketones. The polycondensation proceeded in tetramethylene sulfone in the presence of anhydrous potassium carbonate and afforded the new cardo PEKs in nearly quantitative yields with inherent viscosities of 0.77–0.85 dL/g. High molecular weight PEKs having number‐average molecular weights (M_n's) in the range of 38,900–40,600 g/mol with the polydispersity index ranged from 1.97 to 2.06 are all amorphous and show high glass transition temperatures ranging from 210°C to 254°C, excellent thermal stability, and the temperatures at the 5% weight loss are over 538°C with char yields above 60% at 700°C in nitrogen. These new PEKs are all soluble in polar aprotic solvents such as N‐methyl‐2‐pyrrolidone and N, N′‐dimethylacetamide and could also be dissolved in chloroform and tetrahydrofuran. All the polymers formed transparent, strong, and flexible films with tensile strengths of 78–84 MPa, Young's moduli of 2.54–3.10 GPa, and elongations at break of 14–18 %. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and characterization of novel sulfonated poly(arylene ether ketone)s derived from 4,4'-sulfonyldiphenol

Summary Novel sulfonated poly(arylene ether ketone)s were prepared directly by aromatic nucleophilic polycondensation of 4,4'-sulfonyldiphenol with various ratios of 4,4'-difluorobenzophenone to 5,5'-carbonylbis(2-fluorobenzenesulfonate) in dimethyl sulfoxide. The resulting polyelectrolytes were characterized by IR, NMR, TGA and DSC. The 10% weight loss temperature of the products is higher than 510°C, and their glass transition temperature is above 260°C. The introduction of 4,4'-sulfonyldiphenol with powerful electron-withdrawing group, -SO₂₋, into the main chain of sulfonated poly(arylene ether ketone)s improves the thermal stability against desulfonation. The ion-exchange capacity and swelling of the polyelectrolyte membranes were measured, which are higher than 1.23meq/g and not higher than 20.9%, respectively. The membranes show very good perspectives in polymer electrolyte fuel cell (PEMFC) application. Received: 27 March 2002 / Revised version: 7 May 2002 / Accepted: 13 May 2002     

Effects and properties of poly(arylene ether benzonitrile)s of various molecular weights blended with sulfonated poly(ether ether ketone)

Poly(arylene ether benzonitrile) (PAEBN) was synthesized with 2,6‐dichlorobenzonitrile and biphenol. PAEBNs with various molecular weights (MWs), 1,640,000 and 185,000 g/mol, were synthesized by control of the stoichiometry of the monomers and were blended with sulfonated poly(ether ether ketone) (SPEEK). The effects of MW on the water uptake, swelling, methanol permeability, and proton conductivity of the SPEEK/PAEBN blend membranes were investigated. The molecular mobility of the SPEEK/PAEBN blends was also examined in this study. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Random sulfonated poly(arylene ether sulfone) and sulfonated poly(arylene ether ketone) membranes for fuel cell applications

In this study, sulfonated poly(arylene ether sulfone) (SPAES) and sulfonated poly(arylene ether ketone) (SPAEK) were randomly synthesized, employing a presulfonation process. This presulfonation process resulted in a more controlled and reproducible sulfonation level. The respective polymers were prepared using 2,2-Bis(4-hydroxyphenyl) propane at 50% molar ratio, which also provided some membrane elasticity. The resulting polymers, each had 25% of the block containing the sulfonic domains (SPAES A 25 and SPAEK A 25). Better conductive membranes were achieved for the random sulfone polymers than for the random ketone polymers, with values, respectively, of 0.24 and 0.07 S cm⁻¹ at 80°C. The lower proton conductivity from the ketone-based polymer was compensated with very low methanol permeability (0.25 × 10⁻⁶ cm² s⁻¹) and outstanding oxidative stability. The selectivity of both polymer membranes exceeded the reported values for the state-of-the-art Nafion® 117 and other commercially available options. Both polymer membranes, with their unique combination of ionic domains, elastomeric blocks, and resulting morphology, could be viable candidates for fuel cell applications.     

Polymer electrolyte membranes derived from novel fluorine-containing poly(arylene ether ketone)s by controlled post-sulfonation

Precise assignment with ¹H, ¹³C and some two dimensional NMR measurements showed that sulfonation reaction by concentrated sulfuric acid at 30 °C of fluorine-containing poly(arylene ether ketone) copolymers derived from 4,4′-bis(2,4,5,6-pentafluorobenzoyl)diphenyl ether (BPDE) and 9,9-bis(4-hydroxypehnyl)fluorene (HF) and 2,2-bis(4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane (6FBA) yielded quantitative introduction of sulfonic groups onto 2- and 7-positions of fluorene ring in HF unit. A series of sulfonated poly(arylene ether ketone)s with different ion exchange capacity was prepared by using this method with different compositions of HF and 6FBA, and membranes obtained from these polymers were characterized by TGA, moisture and water uptake, proton conductivity, methanol permeability, and Fenton testing. These membranes showed sufficient thermal stability, high proton conductivity at high humidified condition for PEFC and good balance in proton conductivity in water and methanol permeability for DMFC. On the other hand, they showed relatively high swelling by water probably due to weak intermolecular interaction caused by the existence of fluorine atoms in the polymer structure.     

Crosslinking of poly(arylene disulfide)s and poly(arylene sulfane)s derived from cyclic(arylene disulfide) oligomers

Cyclic(arylene disulfide) and polycyclic(arylene sulfide) oligomers were synthesized by catalytic oxidation of arylenedithiols or arylenetrithiols with oxygen in the presence of a copper‐amine catalyst. These cyclic(arylene sulfide) oligomers can undergo free radical ring‐opening polymerization at an elevated temperature in the melt or solution. Polycyclic(arylene sulfide) oligomers can be used to crosslink poly(arylene disulfide)s and poly(arylene sulfane)s derived from cyclic(arylene disulfide) oligomers and elemental sulfur. The crosslinking reactions were investigated by differential scanning calorimetry and by solubility of the cured products. The minimum concentrations of polycyclic(arylene sulfide) oligomers for producing a well crosslinked poly(arylene disulfide) and poly(arylene sulfane) are 7 wt % and 10 wt %, respectively. The crosslinking reactions between poly(arylene disulfide)s, poly(arylene sulfane)s, and triallyl‐1,3,5‐triazine‐2,4,6(1H,3H,5H)‐trione (TTT) were also investigated. TTT is more efficient for crosslinking than the synthesized polycyclic(arylene disulfide) oligomers. The crosslinkable poly(arylene disulfide)s and poly(arylene sulfane)s could be potentially used as high temperature coatings, sealants, adhesives, and as matrices for high performance thermoset composites. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3069–3077, 1999     

Characterization of chloro-fluorinated poly(arylene ether)s for optical waveguide application

Summary Optical polymers which exhibit good thermal stability, controllable refractive index, and low optical loss in the optical communication wavelengths of 1.3 and 1.55 μm were synthesized from 4,4'-(hexafluoroisopropylidene)diphenol (bisphenol AF) and decafluorobiphenyl. The copolymers were prepared by the appropriate molar ratio of 4,6-dichlororesorcinol and bisphenol AF with decafluorobiphenyl. Optical properties such as refractive index and absorption behavior in the near IR region of the resulting polymers were characterized. As the content of chlorine was increased, the refractive indices of polymer were increased without causing further optical loss. Embedded optical waveguides were fabricated by using fluorinated and chloro-fluorinated poly(arylene ether)s. Received: 2 June 1998/Revised version: 27 July 1998/Accepted: 4 August 1998     

Preparation and performance of crosslinked poly(arylene ether)s containing azobenzene chromophores

A series of novel poly(arylene ether)s with crosslinked groups and different azobenzene chromophores contents (azo-CPAEs: PAE-allyl20%-azo20%, PAE-allyl20%-azo40%, PAE-allyl20%-azo60%) were synthesized from a new bisfluoro monomer, (2,6-difluorophenyl)-(4-hydroxyphenyl)methanone. Their chemical structures were characterized by means of UV-vis and FI-IR. The thermal properties of the polymers were investigated by TGA and DSC, indicating the polymers had high glass transition temperatures (T_g > 147 °C) and good thermal stability (T_d5 > 360 °C) even when the contents of azobenzene chromophores was high to 60%. And the influence of thermal crosslinking on the performance of PAE-allyl20%-azo20%, a typical one of the series, was investigated. T_g of PAE-allyl20%-azo20% increased with the increase of heating time when heat-treated at 250 °C for 20, 40 and 60 min, indicating the crosslink degree of the polymer increased. After heat-treated for 60 min, T_g of PAE-allyl20%-azo20% increased to 175 °C from 147 °C before thermal crosslinking. Upon irradiation with a 532 nm neodymium doped yttrium aluminum garnet (Nd:YAG) laser beam, the remnant value of the polymer PAE-allyl20%-azo20% before and after the thermal crosslinking were 81 and 96%, respectively, meaning that the PAE-allyl20%-azo20% after thermal crosslink showed more stable photoinduced alignment than that before thermal crosslinking.