Synthesis and characterization of novel sodium sulfonate-functionalized poly(ether ether ketone)s containing cyclohexyl side groups

Novel water insoluble sodium sulfonate-functionalized poly(ether ether ketone)s containing cyclohexylidene in the main chain with degree of sulfonation up to 2.0 were synthesized from nucleophilic polycondensation of 5, 5'-carbonylbis (2-fluorobenzenesulfonate), 4, 4'-difluorobenzophenone and 4, 4'-cyclohexylidenebisphenol. The polymers showed excellent thermal stability and good water resistance as well. The DSC diagrams and WAXD patterns indicated an amorphous morphological structure of these polymers. A comprison of some properties between these copolymers and polymers derived from bisphenol A was given.

Synthesis of poly(ether ether ketone)s with high content of sodium sulfonate groups as gas dehumidification membrane materials

Sodium sulfonate-functionalized polyether ether ketone)s derived from Bisphenol A with a degree of sulfonation up to 2.0 were synthesized by aromatic nucleophilic polycondensation of various amounts of 5,5-carbonylbis(2-fluorobenzenesulfonate) (1), 4,4'-diflurobenzophenone (2) and Bisphenol A (2). Copolymers showed excellent thermal stability and good mechanical properties. The selectivity of water vapor over nitrogen of membranes prepared from copolymers 3a and 3h was determined to be 3.43 x 10(6) and 1.05 x 10(7), respectively.

Synthesis and characterization of a series of high sulfonated poly(ether ether ketone)s

A series of high sulfonated poly(ether ether ketone)s were prepared by copolymerization of sodium 5,5 ' -carbonylbis (2-fluorobenzenesulfonate)(2),4,4 ' -difluorobenzophenone (1) and bisphenol A(3) in the presence of potassium carbonate in dimethylsulfoxide. The copolymers were characterized by IR and DSC, The influence of degree of sulfonation on the properties of copolymers, such as component, thermal stability, solubility and filming ability, was studied.

Novel sodium sulfonate-functionalized poly(ether ether ketone)s derived from 4,4 '-thiodiphenol

Novel sodium sulfonate-functionalized poly(ether ether ketone)s derived from 4,4'-thiodiphenol with degree of sulfonation up to 2.0 were synthesized by nucleophilic polycondensation of various amount of 5,5 '-carbonylbis(2-fluorobenzenesulfonate) (1) and 4,4'-difluorobenzophenone (2) with 4,4'-thiodipheno (3). Component and structure of the polymers were confirmed by TR, NMR and elemental analysis. Wide angle X-ray diffraction patterns indicated an amorphous structure of the polymers. All the polymers showed excellent thermal stability and poor solubility in water. (C) 2001 Elsevier Science Ltd. All rights reserved.

Synthesis of cyclic precursors of poly(ether ether ketone)

A novel synthetic route to cyclic PEEK precursors is described. These new cyclic oligomers have been prepared from hydroquinone and N-phenyl(4,4'-difluorodiphenyl) ketimine. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis unambiguously confirmed the cyclic nature.

Crystallization kinetics of poly(ether ether ketone) (PEEK) from its metastable melt

After isothermal crystallization of the amorphous poly(ether ether ketone), double endothermic behaviour can be found through differential scanning calorimetry experiments. During the heating scan of semicrystalline PEEK, a metastable melt, which comes from the melt of the thinner lamellar crystal populations, can be obtained between these two endotherms. The metastable melt can recrystallize immediately just above the lower melting temperature and form slightly thicker lamellae than the original ones. The thickness and the perfection depend upon the crystallization time and the crystallization temperature. By comparing the TEM morphological observations of the samples before and after partial melting, it can be shown that lamellar crystals, having different thermodynamic stability, form during isothermal crystallization. After partial melting, only the type of lamellar crystal exhibiting the higher thermodynamic stability remains. Wide angle X-ray diffraction measurements shows a slightly change in the crystallinity of the samples before and after the partial melting. Small angle X-ray scattering results exhibit a change in the long period of the lamellar crystals before and after the partial melting process. The crystallization kinetics of the metastable melt can be determined by means of differential scanning calorimetry. The kinetic analysis showed that the isothermal crystallization of the metastable PEEK melt proceeds with an Avrami exponent of n = 1.0 similar to 1.4, reflecting that probably one-dimensional or an irregular line growth of the crystal occurred between the existing main lamellae with heterogeneous nucleation. (C) 1998 Elsevier Science Ltd. All rights reserved.

Synthesis of novel cyclic aryl ether thioether ketone (Sulfone) oligomers

Two kinds of macrocyclic oligomers containing aromatic sulfide linkages have been synthesized by the solution polycondensation in high yield. The cyclic compounds were characterized by H-1 and C-13 NMR, by and MALDI - TOF MS.

Sodium sulfonate-functionalized poly(ether ether ketone)s

A new monomer, sodium 5,5'-carbonylbis(2-fluorobenzenesulfonate) (1), was synthesized by sulfonation of 4,4'-difluorobenzophenone (2) with fuming sulfuric acid. Poly(ether ether ketone)s containing sodium sulfonate groups were synthesized directly via aromatic nucleophilic substitution from the sodium sulfonate-functionalized monomer 1 and Bisphenol A (3) in the presence of potassium carbonate in dimethyl sulfoxide. The polycondensation proceeds without any side reactions. The differential scanning calorimetry measurement indicated that the polymers are amorphous and the glass transition temperatures increase with the content of sodium sulfonate groups in the polymer chain. The degree of substitution with sodium sulfonate groups has strong influence on their thermal stability and solubility.

Studies on poly(ether ether ketone ketone) poly(ether biphenyl ether ketone ketone) copolymers and blends

We synthesized a series of polymers: poly(ether ether ketone ketone)(PEEKK), poly(ether biphenyl ether ketone ketone) (PEBEKK) and their copolymer by polycondensation, We also prepared a series of PEEKK-PEBEKK blends, By using DSC method, we found that T-g of the copolymers and the blends rose with the increasing of biphenyl contents in the polymers, T-c of the copolymers and the blends is higher than the corresponding homopolymer. From the results, we think that PEEKK-PEBEKK copolymer and blends are miscible and the copolymer is random.

Liquid crystalline polymer as a processing agent in blends of poly(ether-ketone)/LCP70

Blends of a liquid crystalline thermotropic copolyester (LCP70) and an amorphous phenolphthalein based poly(ether-ketone)(PEK-C) with two viscosities were prepared by melt blending. The blends' morphology, rheological and mechanical properties were investigated by DSC, SEM, mechanical and rheological tests. It was observed that the optimum composition of the PEK-C/LCP70 blend was 10 wt% LCP for both mechanical and rheological properties. When the LCP content was less than 10%, the LCP phase existed as finely dispersed fibrous domains with a diameter of about 1 mu m in the matrix, and both tensile and flexural properties were improved. In contrast, when the LCP content reached 20% or more, the LCP domains coalesced to ellipsoidal particles with a diameter of about 5 mu m, and the mechanical properties decreased as a result. It is demonstrated that pure PEK-C with a high viscosity which was difficult to process by melt extrusion, could be extruded conveniently when 10% LCP70 was incorporated. It is emphasized that LCP not only can be used as a reinforcing phase but also an effective processing agent for engineering thermoplastics, especially for those with high viscosity and narrow processing window. (C) 1997 Elsevier Science Ltd.

Reinforced effect of wollastonite on phenolphthalein poly(ether ketone)

The mechanical properties of wollastonite-filled phenolphthalein poly(ether ketone) (PEK-C) composites have been studied at room temperature and 200 degrees C. The dispersion of wollastonite particles in PEK-C matrix were investigated by means of scanning electron microscope. The modulus and strength of the composites increased with filler content. The reinforced effect of wollastonite on PEK-C is more marked at elevated temperature. The glass transition temperature of the composites is higher than that of PEK-C and is independent of filler content. The restriction effect of tiller particles on the molecular mobility of the polymer matrix should be attributed to the reinforcement. (C) 1997 John Wiley & Sons, Inc.

The double-melting behavior of poly(ether diphenyl ether ketone)

Poly(ether diphenyl ether ketone) (PEDEK) synthesized by the nucleophilic route has the following chemical structure: [GRAPHICS] At some given temperatures for a given time isothermally crystallized PEDEK sample exhibits two endothermic peaks which are similar to PEEK and PEEKK The melting behavior of PEDEK crystallized from the glassy state is investigated through differential scanning calorimeter (DSC). We consider that the high-melting peak is related to the perfect crystals and the low-melting peak is associated with a few imperfect crystals. (C) 1997 John Wiley & Sons, Inc.

Rheological properties of phenophthalein poly(ether ether ketone)

The rheological properties of the novel engineering thermoplastic phenophthalein poly(ether ether ketone) (PEK-C) have been investigated using both a rotational and a capillary rheometer. The dependence of the viscosity on the shear rate and temperature was obtained. The activation energy was evaluated both from the Arrhenius and the Williams-Landel-Ferry (WLF) equation. An estimate for the proper E(eta) (dependent only on the chemical structure of the polymer) has been found from the WLF equation at temperatures about T-g + 200 degrees C. Measurements of the die swell have been performed. The first normal stress differences were evaluated from the die swell results and compared with the values obtained from the rotational rheometer at low shear rates.

Relationship between viscoelastic transition and yield behavior of phenolphthalein poly(ether ketone)

The viscoelastic behavior of phenolphthalein poly(ether ketone) (PEK-C) and its relationship to yielding was studied. The following phenomena were observed: (1) The relaxation behavior at strain near yield closely approximated that at low strain but near the T-g; (2) the temperature and strain rate dependence of yield stress could be modeled by the one-process Eyring theory and the value of the activation volume was the same as that of the glass transition; and (3) according to the Zhurkov-Bueche equation, the cu transition was related to the yield behavior. All these results indicated that the glass transition was the main factor that controlled the yield behavior. (C) 1996 John Wiley & Sons, Inc.