Blends of phenolphthalein poly(ether ether ketone) and a thermotropic liquid crystalline copolyester

Blends of phenolphthalein poly(ether ether ketone) (PEK-C) and a thermotropic liquid crystalline copolyester (LCP), poly[(1-phenylethyl-p-phenylene terephthalate)-co-(1-cumyl-p-phenylene terephthalate)], was prepared via melt mixing. The studies of differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) indicate that the PEK-C/LCP blends display two glass transition temperatures which correspond to those of PEK-C- and LCP-rich phases, respectively. The PEK-C/LCP blends were judged to be partially miscible. Scanning electron microscopy (SEM) was employed to examine the morphology of the blends, and it was observed that all the PEK-C/LCP blends displayed a phase-separated structure. The interface between the PEK-C- and LCP-rich phases is poor. The Young's modulus of the PEK-C/LCP blends was found to increase with LCP content due to the high modulus of the LCP. However, the tensile strength and the elongation at break of the blends greatly decreases with increase of LCP content, owing to the poor interfacial adhesion. From the thermogravity analysis (TGA), it was observed that all the blends exhibited a two-step weight loss mechanism, and the thermal degradation onset temperature of the blends was lowered with the addition of LCP content. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1923–1931, 1998     

环氧树脂/聚芳醚酮共混物的制备研究

用热塑性酚酞型聚芳醚酮树脂(PEK-C)与环氧树脂(EP)熔融共混,并以4,4′-二氨基二苯甲烷(DDM)为固化剂制备新型改性环氧树脂。用SEM观察固化物的微观相结构,用DMA、TG-DTG测试固化物的热性能及2相的相容性。结果表明,PEK-C质量分数小于10%时可以分子或纳米尺度(<100nm)均匀分散于环氧树脂基体中;PEK-C的含量增大,相分离现象明显,固化物的Tg升高,但在300℃以上的高温热稳定性能下降。     

Miscibility and crystallization behavior of poly(ether ether ketone ketone)/poly(ether imide) blends

The miscibility and crystallization behavior of poly(ether ether ketone ketone) (PEEKK)/poly(ether imide) (PEI) blends prepared by melt‐mixing were investigated by differential scanning calorimetry. The blends showed a single glass transition temperature, which increased with increasing PEI content, indicating that PEEKK and PEI are completely miscible in the amorphous phase over the studied composition range (weight ratio: 90/10–60/40). The cold crystallization of PEEKK blended with PEI was retarded by the presence of PEI, as is apparent from the increase of the cold crystallization temperature and decrease of the normalized crystallinity for the samples anealed at 300°C with increasing PEI content. Although the depression of the apparent melting temperature of PEEKK blended with PEI was observed, there was no evidence of depression in the equilibrium melting temperature. The analysis of the isothermal crystallization at 313–321°C from the melt of PEEKK/PEI (100/0, 90/10, and 80/20) blends suggested that the retardation of crystallization of PEEKK is caused by the increase of the crystal surface free energy in addition to the decrease of the mobility by blending PEI with a high glass transition temperature. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 769–775, 2001     

Rheological properties in blends of poly(aryl ether ether ketone) and liquid crystalline poly(aryl ether ketone)

Rheological properties of the blends of poly(aryl ether ether ketone) (PEEK) with liquid crystalline poly(aryl ether ketone) containing substituted 3‐trifluoromethylbenzene side group (F‐PAEK), prepared by solution precipitation, have been investigated by rheometer. Dynamic rheological behaviors of the blends under the oscillatory shear mode are strongly dependent on blend composition. For PEEK‐rich blends, the systems show flow curves similar to those of the pure PEEK, i.e., dynamic storage modulus G′ is larger than dynamic loss modulus G″, showing the feature of elastic fluid. For F‐PAEK‐rich systems, the rheological behavior of the blends has a resemblance to pure F‐PAEK, i.e., G″ is greater than G′, showing the characteristic of viscous fluid. When the PEEK content is in the range of 50–70%, the blends exhibit an unusual rheological behavior, which is the result of phase inversion between the two components. Moreover, as a whole, the complex viscosity values of the blends are between those of two pure polymers and decrease with increasing F‐PAEK content. However, at 50% weight fraction of PEEK, the viscosity‐composition curves exhibit a local maximum, which may be mainly attributed to the phase separation of two components at such a composition. The changes of G′ and G″ with composition show a trend similar to that of complex viscosity. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4040–4044, 2006     

Cure kinetics and morphology of blends of epoxy resin with poly (ether ether ketone) containing pendant tertiary butyl groups

The cure kinetics and morphology of diglycidyl ether of bisphenol-A (DGEBA) epoxy resin modified with a poly (ether ether ketone) based on tertiary butyl hydroquinone (PEEK-T) cured with diamino diphenyl sulphone (DDS) were investigated using differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and dynamic mechanical thermal analysis (DMTA). The results obtained from DSC were applied to autocatalytic and diffusion controlled kinetic models. The reaction mechanism broadly showed autocatalytic behaviour regardless of the presence of PEEK-T. At higher PEEK-T concentration, more diffusion controlled mechanism was observed. The rate of curing reaction decreased with increase in thermoplastic content and also with the lowering of curing temperature. The activation energies of the blends are higher than that of the neat resin. The blends showed a phase separated morphology. The dispersed phase showed a homogeneous particle size distribution. The T_g of the neat resin decreased with the decrease in cure temperature. Two T_g's corresponding to the epoxy rich and thermoplastic rich phases were observed in the dynamic mechanical spectrum. The storage modulus of 10 and 20 phr PEEK-T blends are found to be greater than the neat resin.     

含氟聚醚醚酮增韧环氧树脂相形貌与性能研究

采用SEM观察了热塑性含氟结构聚醚醚酮(6FPEEK)共混增韧环氧树脂的浇铸体脆断断口相形貌,测试了浇铸体的力学性能及动态机械性能,通过统计和数学分析建立了冲击韧性(αk)、热塑颗粒粒径(d)和粒间距(D)间的半定量关系。结果表明,该体系可得到连续相为环氧树脂而分散相为热塑颗粒的相结构,热塑相颗粒尺寸较为统一,且随热塑性树脂含量的增加而增大;6FPEEK含量增加对拉伸强度的影响不大,环氧树脂和热塑性塑料的结合界面差导致了冲击韧性在6FPEEK质量分数达到9.09%时出现峰值而后下降;该增韧体系的增韧机理可能为刚性粒子增韧。     

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°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 filler particles on the molecular mobility of the polymer matrix should be attributed to the reinforcement. © 1997 John Wiley & Sons, Inc. J Appl Polym 65: 649–653, 1997     

Miscibility and interchange reactions in blends of bisphenol-A-type epoxy resin and poly(ethylene terephthalate)

Blends of diglycidyl ether of bisphenol A (DGEBA) and poly(ethylene terephthalate) (PET) were prepared by solution casting from 1,1,2,2-tetrachloroethane. The miscibility and interchange reactions in DGEBA–PET blends were studied by differential scanning calorimetry (DSC) and optical microscopy. PET was found to be miscible with DGEBA, as revealed by the existence of a single composition-dependence glass transition temperature (T_g). Interchange reactions between DGEBA and PET components in the blends at elevated temperatures were proven by appearance of the enhanced glass transition temperatures and the marked decrease in the crystallinity of PET. These results are attributed to the formation of copolymers based on the blend components due to interchange reactions. The morphological observations confirmed that there existed interchange reactions between DGEBA and PET. There also existed a self-crosslinking reaction among the DGEBA molecules. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 639–647, 1999     

Thermal behavior of poly(ether ketone ketone)/thermoplastic polyimide blends

The phase behavior and crystallization of poly(ether ketone ketone)/polyimide blends was investigated by differential scanning calorimetry and dynamic mechanical analysis, and chemical interactions in the blends were probed by Fourier‐transform infrared spectroscopy. Amorphous blends were miscible over the entire range of composition, although mixing was most favorable at higher thermoplastic polyimide concentrations. Blending suppressed crystallization, especially of the minor component, but crystallization of both components, however, did occur in most of the blends. While blends quenched from the melt exhibited only a single amorphous phase, melt crystallized blends appeared to possess two amorphous phases with different compositions. Shifts in the vibration frequencies of the carbonyl and imide bonds were inconsistent with the development of strong, specific intermolecular interactions, but may be explained by a disruption of the packing of the two homopolymers by nature of the mixing. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1227–1235, 2004     

Synthesis and properties of poly(aryl ether ketone ketone)/poly(aryl ether ether ketone ketone) copolymers with pendant cyano groups

2,6‐Diphenoxybenzonitrile (DPOBN) was synthesized by reaction of phenol with 2,6‐difluorobenzonitrile in N‐methyl‐2‐pyrrolidone in the presence of KOH and K₂CO₃. Poly(aryl ether ketone ketone)/poly(aryl ether ether ketone ketone) copolymers with pendant cyano groups were prepared by the Friedel–Crafts electrophilic substitution reaction of terephthaloyl chloride with varying mole proportions of diphenyl ether and DPOBN using 1,2‐dichloroethane as solvent and N‐methyl‐2‐pyrrolidone as Lewis base in the presence of anhydrous AlCl₃. The resulting polymers were characterized by various analytical techniques, such as FT‐IR, differential scanning calorimeter, thermal gravimetric analysis, and wide‐angle X‐ray diffraction. The crystallinity and melting temperature of the polymers were found to decrease with increase in concentration of the DPOBN units in the polymer. Thermogravimetric studies showed that all the polymers were stable up to 514°C in N₂ atmosphere. The glass transition temperature was found to increase with increase in concentration of the DPOBN units in the polymer when the molar ratios of DPOBN to DPE ranged from 10/90 to 30/70. The copolymers containing 30–40 mol % of the DPOBN units exhibit excellent thermostability at (350 ± 10)°C and have good resistance to acidity, alkali, and organic solvents. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3601–3606, 2007     

环氧端基酚酞聚芳醚腈改性环氧树脂胶粘剂性能的研究

通过差示扫描量热 (DSC)、热解重量分析 (TGA)和粘接强度的测定 ,对环氧端基酚酞聚芳醚腈改性的环氧树脂胶粘剂的性能进行了研究     

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     

Compatibility studies of sulfonated poly(ether ether ketone)–poly(ether imide)–polycarbonate ternary blends

Binary blends of the sulfonated poly(ether ether ketone) (SPEEK)–poly(ether imide) (PEI) and SPEEK–polycarbonate (PC), and ternary blends of the SPEEK–PEI–PC, were investigated by differential scanning calorimetry. SPEEK was obtained by sulfonation of poly(ether ether ketone) using 95% sulfuric acid. From the thermal analysis of the SPEEK–PEI blends, single glass transition temperature (T_g) was observed at all the blend composition. For the SPEEK–PC blends, double T_gs were observed. From the results of thermal analysis, it is suggested that the SPEEK–PEI blends are miscible and the SPEEK–PC blends are immiscible. Polymer–polymer interaction parameter (χ₁₂) of the SPEEK–PEI blends was calculated from the modified Lu and Weiss equation, and found to range from −0.011 to −0.825 with the blend composition. For the SPEEK–PC blends, the χ₁₂ values were calculated from the modified Flory–Huggins equation, and found to range from 0.191 to 0.272 with the blend composition. For the SPEEK–PEI–PC ternary blends, phase separation regions that showed two T_gs were found to be consistent with the spinodal curves calculated from the χ₁₂ values of the three binary blends. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 2488–2494, 2000     

Effect of PES on the morphology and properties of proton conducting blends with sulfonated poly(ether ether ketone)

Development of alternate materials to Nafion, based on ionically conducting polymers and their blends is important for the wider applications of proton exchange membrane fuel cells. In this work, blends of sulfonated poly(ether ether ketone) (SPEEK) with poly(ether sulfone) (PES) are investigated. SPEEK with various ion exchange capacity (IEC) was prepared and blended with PES, which is nonionic and hydrophobic in nature. A comparative study of the water uptake, proton conductivity, and thermo‐mechanical characteristics of SPEEK and the blend membranes as a function of the IEC is presented. Addition of PES decreases the water uptake and conductivity of SPEEK. Chemical and thermal stability and mechanical properties of the membrane improve with the addition of PES. The effect of water content on the thermo‐mechanical properties of membranes was also studied. The morphology of blend membranes was studied using SEM to understand the microstructure and miscibility of the components. On the basis of the results, a plausible microstructure of the blends is presented, and is shown to be useful in understanding the variation of different properties with blending. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and properties of copolymers of poly(ether ketone ketone) and poly(ether amide ether amide ether ketone ketone)

Poly(aryl ether ketone)s (PAEKs) are a class of high‐performance engineering thermoplastics known for their excellent combination of chemical, physical and mechanical properties, and the synthesis of semicrystalline PAEKs with increased glass transition temperatures (T_g) is of much interest. In the work reported, a series of novel copolymers of poly(ether ketone ketone) (PEKK) and poly(ether amide ether amide ether ketone ketone) were synthesized by electrophilic solution polycondensation of terephthaloyl chloride with a mixture of diphenyl ether and N,N′‐bis(4‐phenoxybenzoyl)‐4,4′‐diaminodiphenyl ether (BPBDAE) under mild conditions. The copolymers obtained were characterized using various physicochemical techniques. The copolymers with 10–35 mol% BPBDAE are semicrystalline and have markedly increased T_g over commercially available poly(ether ether ketone) and PEKK due to the incorporation of amide linkages in the main chain. The copolymers with 30–35 mol% BPBDAE not only have high T_g of 178–186 °C, but also moderate melting temperatures of 335–339 °C, having good potential for melt processing. The copolymers with 30–35 mol% BPBDAE have tensile strengths of 102.4–103.8 MPa, Young's moduli of 2.33–2.45 GPa and elongations at break of 11.7–13.2%, and exhibit high thermal stability and good resistance to organic solvents. Copyright © 2010 Society of Chemical Industry     

Fine poly(ether ether ketone) powders

The physical form of polymers is often important for carrying out subsequent processing operations. For example, fine powders are desirable for molding and sintering compounds because they consolidate to produce void free components. The objective of this work is to prepare fine polymeric particulates suitable for processing into fiber reinforced polymer matrix composites. Micron size particles of poly(ether ether ketone) (PEEK) were prepared by rapidly quenching solutions of these materials. PEEK pellets were dissolved at temperatures near the PEEK melting point in a mixture of terphenyls and quaterphenyls; then the solution was quenched to a temperature between the T_g and T_m (≈ 225°C) by adding a room temperature eutectic mixture of diphenyl ether and biphenyl. A supersaturated, metastable solution of PEEK resulted, causing rapid nucleation. Fine PEEK particles rapidly crystallized from this solution. The average particle size was measured using transmission electron microscopy, atomic force microscopy, and by light scattering of aqueous suspensions which had been fractionated by centrifugation. The average particle diameter was about 0.6 μm. Three dimensional photomicrographs obtained via atomic force microscopy showed some aggregates in the suspensions. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1571–1578, 1997     

Effects of heat treatment on the properties of heterogeneous cation permeable membranes from blends of poly(ether sulfone)/sulfonated poly(phenylene sulfide) and phenolphthalein poly(ether ether ketone)/sulfonated poly(phenylene sulfide)

The effects of heat treatment on the properties of membranes prepared from blends of poly(ether sulfone)/sulfonated poly(phenylene sulfide) (SPPS) and phenolphthalein poly(ether ether ketone)/SPPS were studied in detail. The membranes' fundamental properties, including water content, transport number, diffusion coefficient of electrolytes, flux, and so on, changed with both treated temperature and time, whereas the ion‐exchange capacity and electrical resistance remained approximately unchanged. The trends may have been due to the possible structural change resulted from the shrinking of the polymers forming the membranes. Furthermore, the membranes also retained a good physical appearance at temperatures below 220°C. Therefore, a series of heterogeneous membranes with desired conductivities and selectivities as well as proper water contents, which could satisfy different industrial purposes, such as electrodialysis, diffusional dialysis, and proton exchange, were achieved by simple heat treatment for a proper time and at a proper temperature. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 494–499, 2005     

Synthesis and characterization of poly(ether ketone ether ketone ketone)/poly(ether ether ketone ketone) copolymers containing naphthalene and pendant cyano groups

2,6‐Bis(β‐naphthoxy)benzonitrile (BNOBN) was synthesized by reaction of β‐naphthol with 2,6‐difluorobenzonitrile in N‐methyl‐2‐pyrrolidone (NMP) in the presence of KOH and K₂CO₃. Poly(ether ketone ether ketone ketone)(PEKEKK) /poly(ether ether ketone ketone) (PEEKK) copolymers containing naphthalene and pendant cyano groups were obtained by electrophilic Friedel‐Crafts polycondensation of terephthaloyl chloride (TPC) with varying mole proportions of 4,4′‐diphenoxybenzophenone (DPOBP) and 2,6‐bis(β‐naphthoxy)benzonitrile (BNOBN) using 1,2‐dichloroethane (DCE) as solvent and NMP as Lewis base in the presence of anhydrous AlCl₃. The resulting polymers were characterized by various analytical techniques, such as FTIR, DSC, TG, and WAXD. The results indicated that the crystallinity and melting temperature of the polymers decreased with increase in concentration of the BNOBN units in the polymer, the glass transition temperature of the polymers increased with increase in concentration of the BNOBN units in the polymer. Thermogravimetric studies showed that all the polymers were stable up to 536°C in N₂ atmosphere. The copolymers have good resistance to acidity, alkali, and organic solvents. Because of the melting temperature (T_m) depression with increase in the BNOBN content in the reaction system, the processability of the resultant coplymers could be effectively improved. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

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     

Curing of diglycidyl ether of bisphenol‐A epoxy resin using a poly(aryl ether ketone) bearing pendant carboxyl groups as macromolecular curing agent

BACKGROUND: Reactive thermoplastics have received increasing attention in the field of epoxy resin toughening. This paper presents the first report of using a novel polyaryletherketone bearing one pendant carboxyl group per repeat unit to cure the diglycidyl ether of bisphenol‐A epoxy resin (DGEBA). The curing reactions of DGEBA/PEK‐L mixtures of various molar ratios and with different catalysts were investigated by means of dynamic differential scanning calorimetry and Fourier transform infrared (FTIR) spectroscopy methods. RESULTS: FTIR results for the DGEBA/PEK‐L system before curing and after curing at 135 °C for different times demonstrated that the carboxyl groups of PEK‐L were indeed involved in the curing reaction to form a crosslinked network, as evidenced by the marked decreased peak intensities of the carboxyl group at 1705 cm^?1 and the epoxy group at 915 cm^?1 as well as the newly emerged strong absorptions of ester bonds at 1721 cm^?1 and hydroxyl groups at 3447 cm^?1. Curing kinetic analysis showed that the value of the activation energy (E_a) was the highest at the beginning of curing, followed by a decrease with increasing conversion (α), which was attributed to the autocatalytic effect of hydroxyls generated in the curing reaction. CONCLUSION: The pendant carboxyl groups in PEK‐L can react with epoxy groups of DGEBA during thermal curing, and covalently participate in the crosslinking network. PEK‐L is thus expected to significantly improve the fracture toughness of DGEBA epoxy resin. Copyright © 2009 Society of Chemical Industry