Part 2. Quantitative interpretation of model compound sulfonation

The mechanism and kinetics of sulfonation of two PEEK model compounds in concentrated sulfuric acid were studied. The first model compound (monomer) is representative of a PEEK repeat unit. The second one is a PEEK dimer. Because both model compounds are fluoroarylketone‐ended, the sulfonation reactions were followed by ¹⁹F NMR. The sulfonation reactions were treated following a first‐order kinetics with respect to the unsulfonated PEEK repeat unit. The comparison between the monomer and dimer results showed two different types of sulfonation behaviour. If only one apparent kinetic constant is considered for monomer sulfonation, two kinetic constants were taken into account to describe the dimer sulfonation process. This is due to a rate slowing effect of a sulfonic acid group on the sulfonation of the adjacent PEEK repeat unit. Furthermore, the results also confirm the rate slowing effect of the fluorine atom on the sulfonation of the neighbouring PEEK repeat unit. © 2001 Society of Chemical Industry     

Sulfonation of poly(ether ether ketone)(PEEK): Kinetic study and characterization

Hydrophobic poly(ether ether ketone) (PEEK) were modified by sulfonation at different temperatures (22, 36, 45, and 55°C) and varying period of time with concentrated sulfuric acid used as solvent. A kinetic study was carried out based on the assumption that sulfonation reaction is a second-order reaction, which takes place preferentially in the aromatic ring between the two ether ( O ) links (the first type substitution), and there is only one substituent attached to each repeat unit of the PEEK before the complete substitution of this preferred aromatic ring. More than 100% substitution was observed in experiment. All the data with substitution degree less than 95% agree fairly well with the kinetic behavior of the second-order reaction. The reaction rate coefficient and activation energy for first type substitution were obtained. The sulfonated PEEK samples were characterized in terms of ion-exchange capacity (IEC), ¹H-NMR, contact angle, and solubility. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2651–2660, 2001     

Part 3. General kinetic model of the sulfonation of PEEK fluoroarylketone chain‐end repeat unit

The sulfonation kinetics of the fluoroarylketone chain‐end repeat unit of PEEK was studied. To achieve this objective, the sulfonation reactions of a trimer, a tetramer and a polymer, each fluoroarylketone ended, were followed by ¹⁹F NMR. A general kinetic model was developed to determine the kinetic constants from ¹⁹F NMR data. The reliability of the kinetic model and of its mathematical expression was ensured. The kinetic constants are then calculated and discussed. In particular, they were compared with the dimer rate constants previously determined. Lastly and as a conclusion of this work, a general kinetic model describing the sulfonation of main chain repeat units of PEEK is proposed. © 2001 Society of Chemical Industry     

Preparation of honeycomb films from nitryl poly(ether ether ketone)s via water‐droplet templating

The fabrication of honeycomb‐patterned films from nitryl poly(ether ether ketone)s (PEEK‐NO₂) in a high‐humidity atmosphere was reported in this article. PEEK‐NO₂ was prepared through acid (nitric acid and sulfuric acid) nitration from poly(ether ether ketone)s (PEEK). The obtained polymer, which was characterized by Fourier transform infrared (FT‐IR), X‐ray diffraction (XRD), and differential scanning calorimetry (DSC) showed excellent solubility and thermal stability. Some influence factors on the pattern formation and the fabrication of the porous structure, such as the solution concentration, the solvent, and the atmosphere humidity, were investigated. The results showed that with the increase of the solution concentration, the aperture of the film diminished gradually; the lower the solvents´ boiling point were, the smaller the films´ apertures were and the more regular the pores´ arrange; only under high‐humidity circumstances could obvious and ordered honeycomb films be formed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

聚醚醚酮表面接枝O-羧甲基壳聚糖及其血液相容性研究

采用紫外自引发光接枝在聚醚醚酮表面接枝聚丙烯酸,并进而以此为反应位点,通过共价键结合引入O羧甲基壳聚糖(O-CMC)。采用接触角测定仪、扫描电子显微镜、X射线光电子能谱和血小板粘附实验等对改性聚醚醚酮进行了表征。结果表明,改性聚醚醚酮表面浸润性得到提高,具有抗凝血性能。     

Structural and mechanical characterization of poly(ether ether ketone) (PEEK) and sulfonated PEEK films: Effects of thermal history,sulfonation, and preparation conditions

In this work, virgin and sulfonated poly(ether ether ketone) films (PEEK and SPEEK, respectively) have been studied by dynamic mechanical analysis, modulated differential scanning calorimetry, wide‐angle X‐ray diffraction, birefringence, and optical microscopy. The properties of the unmodified polymer have been addressed to assess the original morphological characteristics and the changes induced by sulfonation. In general, the introduction of ionic groups in the polymer backbone alters dramatically the intrinsic properties of the parent material. The particular thermomechanical response exhibited by PEEK and SPEEK samples, characterized by a hysteresis loop, can be explained by the reversible and irreversible relaxation–orientation of the microstructure, even in the sub‐T_g region. The results showed that the preparation conditions largely determine the nonequilibrium morphological features of both compression‐molded PEEK films and solvent‐cast SPEEK membranes. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 756–774, 2006     

缩水甘油β-萘基醚、正丁基醚共聚物磺酸钠的合成及表征

以硫酸为磺化剂合成了一系列不同组成的缩水甘油 β-萘基醚 -缩水甘油正丁基醚共聚物磺酸钠 ,通过控制聚醚预聚体的组成和聚醚预聚体侧链上芳基的磺化度可控制磺酸聚醚的组成 ,并用 VPO、1HNMR、IR等测定了聚醚预聚体的数均分子量与组成、磺酸聚醚的磺化度。     

Post sulfonation of bisphenol A poly(arylene ethers)

In this study, bisphenol A polyetherimide (PEI) was sulfonated by a novel postsulfonation route using trimethylsilylchlorosulfonate. Different degrees of sulfonation were achieved by varying the mole ratio of the sulfonating agent to the PEI repeat unit and the reaction time. Comparison was made with respect to bisphenol A polysulfone (PSU) to study the influence of electron withdrawing group in the sulfonated poly(arylene ethers) (SPAE) backbone on sulfonation. Structural characterization of SPAE was conducted by ¹H‐NMR and FTIR spectroscopy. The enhanced reaction rate with PSU compared to PEI was attributed to the deactivation of bisphenol A unit due to the stronger electron withdrawing effect of imide group. The sulfonation of PEI was also carried out with chlorosulfonic acid for comparative study. The effects of degree of sulfonation on thermal and mechanical properties of SPAE‐s were studied by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and a tensile testing machine. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Performance of the sulfonated poly ether ether ketone proton exchange membrane modified with sulfonated polystyrene and phosphotungstic acid for microbial fuel cell applications

In this research, the preparation of low cost proton exchange membranes (PEMs) based on sulfonated poly ether ether ketone (SPEEK) for application in the microbial fuel cells (MFCs) is studied. Sulfonated polystyrene (SPS) and phosphotungstic acid (PWA) were employed to improve the performance of PEM through the creation of more proton pathways. At first, the sulfonation of PEEK and polystyrene were performed through two modified methods to obtain uniform and high degree of sulfonation (DS) of the polymers and then, the PEMs were prepared through the solution casting method. Accordingly, the formation of uniform skin layer was confirmed by the SEM micrographs. Blending the aforementioned additives to the SPEEK polymer solution significantly enhanced the proton conductivity, water uptake and durability of the modified membranes. The proton conductivities of SPEEK/SPS and SPEEK/PWA membranes at additive/SPEEK weight ratio of 0.15 were 45.3% and 26.2% higher than that of the commercial Nafion117 membrane, respectively. Moreover, the degradation times for the abovementioned modified membranes were 140 and 350 min which indicated satisfactory oxidation stability. Besides, the aforementioned membranes exhibited two times more water uptake compared to the neat SPEEK membrane. Finally, SPEEK/SPS and SPEEK/PWA membranes produced 68% and 36% higher maximum power in the MFC, compared to the commercial Nafion117 membrane. Therefore, the fabricated PEMs are potentially suitable alternatives to be used in the fuel cell applications.     

Poly(ether ether ketone)/poly(aryl ether sulfone) blends: Relationships between morphology and mechanical properties

Mechanical properties such as the tensile modulus, yield (break) strength, and elongation to break (or yield) are measured for multiphase poly(ether ether ketone) (PEEK)/poly(aryl ether sulfone) (PES) blends. Specimens with three different levels of thermal histories (quenched, as‐molded, and annealed) are prepared in order to study their effects on the mechanical properties of PEEK/PES blends. Synergistic behavior is observed in the tensile modulus and tensile strength of the blends in almost the whole range of compositions. The ductility of quenched blends measured as the elongation to break (yield) shows an unexpected synergistic behavior in the blend containing 90 wt % PEEK, although a negative deviation from additive behavior is observed in the rest of the compositions. A ductile–brittle transition is observed between 50 and 75 wt % PEEK in the blend. The ductile–brittle transition in as‐molded blends shifts to 75–90 wt % PEEK. Annealed blends show predominantly brittle behavior in the whole composition range. The experimental data are further correlated with the theoretically predicted results based on various composite models. Although the prediction based on these equations fails to fit the experimental data in the whole composition range, the simplex equations that are normally used for blends showing synergistic behavior produced a reasonable fit to the experimental data. The mechanical properties obtained for different blend compositions are further correlated with their morphology as observed by scanning electron microscopy. Morphological observation shows a two‐phase morphology in PES‐rich blends, which is an interlocked morphology in which the disperse phase is not clearly visible in PEEK‐rich blends, and a cocontinuous type of morphology for a 50/50 composition. Considerable permanent deformation of both the disperse and matrix phase, especially in the case of quenched tensile specimens, demonstrates the remarkable adhesion present between the two phases. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2887–2905, 2003     

Synthesis and properties of thio‐containing poly(ether ether ketone)s

A series of thio‐containing poly(ether ether ketone) (PEESK) polymers was synthesized by the introduction of thio groups from 4,4′ thiodiphenol (TDP) into the poly(ether ether ketone) (PEEK) structure via reaction between the phenol and aromatic fluoride groups. The effect of the thio groups on the properties of the PEESK materials was investigated. Differential scanning calorimetry (DSC) analysis and X‐ray diffraction (XRD) patterns show a depression in the crystallinity of the PEESKs with incorporation of the content of thio groups in the backbones. The crystalline structure was identified as an orthorhombic structure with lattice constants of a = 7.52 Å, b = 5.86 Å and c = 10.24 Å for all crystallizable PEESKs. The crystalline structures of the thio‐containing PEEK polymers were the same as that of the neat PEEK, which means the thio‐containing block in the whole thio‐containing PEEK molecule is almost excluded from the crystalline structure and the crystals are completely formed by ‘non‐thio’ blocks only. Due to the glass transition temperature (T_g) and melting temperature (T_m) depression with increase in the TDP content in the reaction system, the processability of the resultant thio‐containing PEEKs could be effectively improved. Copyright © 2004 Society of Chemical Industry     

Permeation resistance of poly(ether ether ketone) to hydrogen,nitrogen, and oxygen gases

We studied the gas permeation properties of poly(ether ether ketone) (PEEK) and compared it with two other polymers commonly used in the construction of semiconductor microenvironments, polycarbonate (PC), and poly(ether imide) (PEI). The PEEK specimens consisted of extruded films as well as compression‐ and injection‐molded specimens. The compression‐molded specimens were prepared to achieve the highest crystallinity. Injection‐molded disks, representing products, were milled to a prescribed thickness. Permeation, diffusion, and solubility coefficients were measured on these various PEEK specimens for hydrogen, nitrogen, and oxygen gases. It was found that PEEK generally has better permeation resistance than PC or PEI; showing up to five times lower permeation rates than PC or PEI, depending on grade, crystallinity, and gas. The superior permeation resistance of injection‐molded or extruded PEEK, when compared with similarly processed PC or PEI, comes from its crystallinity. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Crystallization and melting behavior of poly(ether ether ketone)/poly(aryl ether sulfone) blends

The crystallization and melting behavior of poly(ether ether ketone) (PEEK) in blends with poly(aryl ether sulfone) (PES) prepared by melt mixing are investigated by differential scanning calorimetry (DSC) and wide‐angle X‐ray scattering (WAXS). The presence of PES is found to have a notable influence on the crystallization behavior of PEEK, especially when present in low concentrations in the PEEK/PES blends. The PEEK crystallization kinetics is retarded in the presence of PES from the melt and in the rubbery state. An analysis of the melt crystallization exotherm shows a slower rate of nucleation and a wider crystallite size distribution of PEEK in the presence of PES, except at low concentrations of PES, where, because of higher miscibility and the tendency of PES to form ordered structures under suitable conditions, a significantly opposite result is observed. The cold crystallization temperature of the blends at low PES concentration is higher then that of pure PEEK, whereas at a higher PES concentration little change is observed. In addition, the decrease in heat of cold crystallization and melting, which is more prevalent in PEEK‐rich compositions than in pure PEEK, shows the reduction in the degree of crystallinity because of the dilution effect of PES. Isothermal cold crystallization studies show that the cold crystallization from the amorphous glass occurs in two stages, corresponding to the mobilization of the PEEK‐rich and PES‐rich phases. The slower rate of crystallization of the PEEK‐rich phase, even in compositions where a pure PEEK phase is observed, indicates that the presence of the immobile PES‐rich phase has a constraining influence on the crystallization of the PEEK‐rich phase, possibly because of the distribution of individual PEEK chains across the two phases. The various crystallization parameters obtained from WAXS analysis show that the basic crystal structure of PEEK remains unaffected in the blend. Further, the slight melting point depression of PEEK at low concentrations of PES, apart from several other morphological reasons, may be due to some specific interactions between the component homopolymers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2906–2918, 2003     

The sulfonation of poly(ether ether ketone) as investigated by two‐dimensional FTIR correlation spectroscopy

Fourier transform infrared and two‐dimensional correlation (2D‐COS) spectroscopies were used to follow the structural alteration occurring upon sulfonation of poly(ether ether ketone), in concentrated sulfuric acid at room temperature. With the help of high resolution and high sensitivity 2D‐COS, it was possible to locate the aromatic ring in which the substitution has taken place. Two new IR bands at 1288 and 1320 cm^?1 were attributed to substitution occurring on the aromatic ring flanked with two ether groups. Limited oxidation effects of concentrated sulfuric acid manifested itself by the production of new carbonyl species absorbing in the IR at 1720 and 1750 cm^?1 that were attributed to a fluorenone‐type structure and to ester groups. The 2D‐COS analysis showed that the band at 1470 cm^?1 is not only due to the new substitution by sulfone groups and can not be used in the determination of sulfonation degree. Instead, the intensity of the 1490 cm^?1 band, which can be attributed to skeletal ring vibration, was found to correlate well with the degree of sulfonation calculated from ¹H NMR spectroscopy. The infrared spectroscopy combined with 2D‐COS provides a fast and powerful method for qualitative polymer structure verification and help to establish the quantitative analysis. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41242.     

A New Route to Perfluoro(Propyl Vinyl Ether) Monomer: Synthesis of Perfluoro(2‐propoxypropionyl) Fluoride from Non‐Fluorinated Compounds

Perfluoro(2‐propoxypropionyl) fluoride ( 1a ), which is the precursor of the perfluorinated propyl vinyl ether (PPVE) monomer of an industrially important perfluoroalkoxy copolymer (PFA), was synthesized by utilizing direct fluorination of the non‐fluorinated counterpart for the first time. The partially‐fluorinated ester 7 synthesized from the desired perfluorinated acid fluoride 1a itself and the non‐fluorinated alcohol 5 , which has a carbon skeleton corresponding to the desired compound 1a , was perfluorinated by liquid‐phase direct fluorination with elemental fluorine. Degradation of the resulting perfluorinated ester 8 gave 2 mols of the desired acid fluoride 1a . In a sense, this process can be called self‐multiplication of a perfluorinated acid fluoride from a non‐fluorinated alcohol.     

复合成盐剂对聚醚醚酮合成与性能的影响

采用4,4′-二氟二苯甲酮、对苯二酚为原料,以不同比例的碳酸钾和碳酸钠为复合成盐剂,二甲苯为脱水剂,二苯砜为溶剂成功制备了一系列聚醚醚酮(PEEK)树脂。通过傅里叶红外光谱和X射线衍射对PEEK树脂结构进行了表征,证明合成的样品是对苯二酚型PEEK树脂。其次,对所制样品分别进行力学性能、特性黏度、热性能测试,详细地探讨不同钾/钠比例的复合成盐剂对PEEK性能的影响。结果表明,所有样品均展示了优异的力学性能和热性能,其熔点和初始分解温度分别大于330℃和520℃,拉伸强度介于77~101 MPa。此外,当碳酸钾和碳酸钠的物质的量比为7∶3时,PEEK树脂的综合性能达到最优。     

Action of transfer film in improving friction and wear behaviors of iron‐ and copper‐filled poly(ether ether ketone) composites

The composites of poly(ether ether ketone) (PEEK) filled with micrometer‐sized Cu and Fe particles were prepared by compression molding. The friction and wear behaviors of the composites were examined on a pin‐on‐disc friction‐and‐wear tester by sliding PEEK‐based composites against tool steel at a sliding speed of 1.0 m s⁻¹ and a normal load of 19.6N. Optical microscopic analysis of the transfer film and of the worn pin surfaces and wear debris was performed to investigate the wear mechanisms of the composites. It was found that Cu and Fe used as filler considerably decreased the wear rate of PEEK. A thin, uniform, and tenacious transfer film was formed when Cu was used as the filler, and a nonuniform and thick transfer film was formed when Fe was used as the filler. The transfer film played a key role in increasing the wear resistance of the PEEK composites. Plastic deformation was dominant for wear of PEEK–Cu, while abrasion and adhesion were dominant for wear of PEEK–Fe. Because of the strong affinity between Fe as filler and its identical counterpart in the counterface tool steel surface, the adhesion between the PEEK–Fe composite surface and the counterface tool steel surface was thus severe. This contributed to the generation of a thicker transfer film for PEEK–Fe. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 179–184, 2000     

A methanesulfonic acid/sulfuric acid‐based route for easily‐controllable chloromethylation of poly(ether ether ketone)

A mixed methanesulfonic acid/sulfuric acid solvent based chlromethylation of poly(ether ether ketone) (PEEK) is described. Methanesulfonic acid is the solvent, sulfuric acid is the catalyst, and chloromethyl octyl ether (CMOE) is the chloromethylating reagent. ¹H‐NMR spectra confirmed the successful synthesis of chloromethylated PEEK (CMPEEK). The effects of polymer concentration, catalyst/polymer ratio, and reaction temperature on the rate of PEEK chloromethylation were investigated. In order to minimize crosslinking, the PEEK concentration must be kept very low (< 2%). The reaction rate increases with increased catalyst/polymer ratio and reaction temperature. The activation energy of PEEK chloromethylation is 30.9 kJ mol^?1. The extent of reaction for the new route is more easily controllable as compared with the previous sulfuric acid based route. The reaction rate constant at 25°C for the new route is 1.29 h^?1 which is lower than that for chloromethylation by concentrated sulfuric acid at ?10°C (rate constant 1.88 h^?1). As a result, the degree of chloromethylation of CMPEEK can be easily controlled at room temperature using this mixed solvent. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41404.     

磺化聚醚醚酮的合成及其性能表征

采用浓硫酸作为磺化剂,利用两种不同分子量的聚醚醚酮(PEEK)制备了具有不同磺化度的磺化聚醚醚酮(SPEEK)膜,用FTIR 和DSC对SPEEK进行了表征,通过质子交换容量(IEC)对磺化度进行了测定,并对SPEEK膜的质子导电性能进行了研究.结果表明,质子交换容量(IEC)与磺化度均随着反应时间的延长而增大,吸水率也随磺化度的增加而增大.     

Effect of dihydroxydiphenyl ether on poly(ether ether ketone)

A series of modified poly(ether ether ketone) (PEEK) polymers were synthesized by introduction of addition ether groups from dihydroxydiphenyl ether (DHDE) into the PEEK structure. The inherent viscosity of the DHDE-modified PEEK increased with reaction time at 320 °C. DSC thermograms showed the melting points of the obtained PEEK decreased with the increase of the DHDE content in the backbone. The degradation temperature (T_d) was slightly decreased by the introduction of DHDE. The crystallinity as measured via the X-ray diffraction (XRD) increases with the introduction of DHDE into the modified PEEK. The crystalline structure was identified as an orthorhombic structure with lattice constants a = 7.72 Å, b = 5.86 Å, and c = 10.24 Å. Due to the glass transition temperature (T_g) and the melting temperature (T_m) decreasing with the increase of the DHDE content in the reaction system. the processability of the resultant PEEK could be improved through this DHDE modification.