Polysulfone — sulfonated poly(ether ether) ketone blend membranes: systematic synthesis and characterisation

The effect of sulfonated poly(ether ether ketone) (SPEEK) in membrane formation and separation properties has been investigated in polysulfone(PSU)/SPEEK/N-methyl-2-pyrrolidinone (NMP) systems. Charged ultrafiltration/nanofiltration membranes were obtained reliably in the range of 0.5–5 wt.% SPEEK in the polymer blend. All PSU/SPEEK blend membranes had substantially higher water flux, salt rejection, porosity and greatly reduced particle adhesion compared to the PSU base membrane. Further, all of these properties varied systematically with variation of SPEEK content. Reproducibility and stability of the membrane properties was excellent. Pore sizes determined from dextran retention data and AFM measurements showed reasonable agreement. Membranes with 5 wt.% SPEEK demonstrated excellent overall properties. Such membranes had very high permeability, 22.6±1.6×10⁻¹¹ m³ s⁻¹ N⁻¹, 0.999 fractional rejection of 4000 Da dextran, 0.65 rejection of 0.001 M NaCl, and only 0.75 mN m⁻¹ adhesion of a 4 μm silica particle. Such membranes are very promising for scale-up of production and testing on real process streams.     

Robust and High-Wettability Pristine Poly(ether ether ketone)Nanofiber Separator for Heat-Resistant and Safe Lithium-Ion Battery

Separator is a pivotal component of lithium-ion batteries(LIBs) and determines the electrochemical performance and safety. However,with the increase in energy density and application scenarios, commercial polyolefin separators are increasingly unable to undertake heavy responsibility of battery safety protection. Herein, a new kind of nanofiber separator based on poly(ether ether ketone)(PEEK) with excellent thermal stability, self-extinguishing, and superior electrochemical properties is report...     

Poly(ether ether ketone) derivative membranes—a review of their preparation, properties and potential

The present paper gives an overview of the properties and performance of membranes of a poly(ether ether ketone) derivative with a cardo group in the chain, known in the literature as PEEKWC or PEK-C. This is one of the typical examples of a new polymer, emerged in the last two decades, with the potential to be applied as a membrane material in a wide range of application fields. Due to the presence of the cardo group in the backbone, the polymer is soluble in several common organic solvents, in contrast to the traditional poly(ether ketone) (PEK) and poly(ether ether ketone) (PEEK). It is therefore more versatile and its solubility allows the use of nonsolvent-induced phase inversion techniques to prepare membranes with a wide range of different morphologies and transport characteristics. The present review will show the current state of the art and will testify that PEEKWC offers interesting perspectives in especially the fields of gas separation, biomedical applications and—in its sulfonated form-in fuel cells. Examples of successful application in microfiltration, ultrafiltration, nanofiltration, pervaporation, membrane contactors, catalytic membranes and some other applications, such as packaging and molecular imprinting will also be shown.     

Sulfonated poly(ether ether ketone)–silica membranes doped with phosphotungstic acid. Morphology and proton conductivity

Sulfonated poly(ether ether ketone) (SPEEK)–silica membranes doped with phosphotungstic acid (PWA) are presented. The silica is generated in situ via the water free sol–gel process of polyethoxysiloxane (PEOS), a liquid hyperbranched inorganic polymer of low viscosity. At 100 °C and 90% RH the membrane prepared with PEOS (silica content = 20 wt%) shows two times higher conductivity than the pure SPEEK. The addition of small amounts of PWA (2 wt% of the total solid content) introduced in the early stage of membrane preparation brings to a further increase in conductivity (more than three times the pure SPEEK). During membrane formation PWA and the sulfonic acid groups of SPEEK act as catalysts in the conversion of PEOS in silica. Once the membranes are formed, PWA is incorporated in the silica network and acts as proton conductivity enhancer. The correlation between morphology and proton conductivity allows establishing the optimal doping level and preparation procedure. The morphology is studied by transmission electron microscopy (TEM) while the proton conductivity is measured by impedance spectroscopy (IS). The direct methanol fuel cell performance is also investigated.     

Studies of the enthalpy relaxation and the “multiple melting” behavior of semicrystalline poly(arylene ether ether ketone) (PEEk)

We report the results of an investigation by differential scanning calorimetry (DSC) of two mobility controlled processes in the amorphous phas e of semicrystalline PEEK — enthalpy relaxation below the glass transition (T _g) and secondary crystallization aboveT _g. Both result in the observation of an endothermic peak just above the annealing temperature in the DSC scan of the polymer — the enthalpy recovery peak and the low temperature melting peak, respectively. There is a striking similarity in the time and temperature dependence of the endothermic peak for these two processes. These results are reminiscent of those obtained from small strain creep studies of physical aging of semicrystalline PEEK below and aboveT _g.We gratefully acknowledge support of this work by the National Science Foundation, Science and Technology Center for High Performance Polymeric Adhesives and Composites under DMR grant 91-2004 and by an NSF Young Investigator Award (DMR 93-57512).     

Synthesis and Characterization of Fluorine-containing Poly（ether ether ketone）s

<正>Poly(ether ether ketone)s(PEEK) are a class of high performance engineering thermoplastics known for their excellent thermal,mechanical,and electrical properties.This class of advanced materials has currently received considerable attention for potential application in aerospace,electronics,automobile and     

Bis(azobenzocrown ether)s—synthesis and ionophoric properties

Novel biscrowns were successfully synthesized from azobenzocrown ethers containing hydroxyl groups in para position relative to the azo group. The synthesized host molecules, differing in the size of the macrocycles, the length of the linker and their potential to act as sodium or potassium ionophores, were characterized and used as ionophores in classic and miniature (screen-printed) ion-selective electrodes. Metal cation complexation for selected macrocycles was carried out with the use of UV–vis spectroscopy in acetonitrile. The structural features of novel complex have been deduced by X-ray crystallography. X-ray analysis indicated the formation of sandwich structures with two sodium cations encapsulated between two macrocyclic molecules of 13C2.     

Photochemical addition of diethyl ether to β,β,β',β'-tetrakis(trifluoromethyl)divinyl ether

The 1:1 adducts of diethyl and ,,','-tetrakis(trifluoromethyl)divinyl ether (1),i.e., 3,5-(ee)-bis[2,2,2-trifluoro-1-(trifluoromethyl)ethyl]-2,6-dimethyl-1,4-dioxane (2) (3 isomers) and 4-ethoxy-1,1,1-trifluoro-2-trifluoromethyl-3-[3,3,3-trifluoro-2(trifluoromethyl)propenyloxy]pentane (3), have been obtained by UV-irradiation of a solution of divinyl ether1 in diethyl ether. The X-ray structural investigation of the all-(e)-isomer of dioxane (2) has been carried out.Deceased.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 85–88, January, 1994.     

Characterization and modelling of a gasoline containing 1,1-dimethylethyl methyl ether (MTBE), diisopropyl ether (DIPE) or 1,1-dimethylpropyl methyl ether (TAME) as fuel oxygenate based on new isothermal binary vapour–liquid data

Experimental isothermal P–x data at T=313.15 K for seven binary systems (1,1-dimethylethyl methyl ether (MTBE)+2,2,4-trimethylpentane); (1,1-dimethylethyl methyl ether (MTBE)+toluene); (toluene+2,2,4-trimethylpentane); (toluene+1-hexene); (toluene+cyclohexane); (2,2,4-trimethylpentane+1-hexene) and (2,2,4-trimethylpentane+cyclohexane) are reported. Data reduction by Barker’s method provides correlations for G^E using the Margules equation, Wilson, NRTL and UNIQUAC models, which have been applied successfully. We have compared the behaviour in the vapour–liquid equilibrium of the aromatic compounds benzene and toluene and the paraffins heptane and 2,2,4-trimethylpentane. And finally we have modelled a gasoline of five components using the Wilson model, and we have compared the influence of three different ethers used as oxygenated additives in gasolines.     

Synthesis and characterization of trimethoxysilyl-functionalized poly(phthalazinone ether ketone)

A novel alkoxysilyl-functionalized poly(phthalazinone ether ketone)(PPEK)was prepared for the boundary lubricant application in micro-electro-mechanical system(MEMS).The synthesis of functionalized PPEK was started from the hydro- xylation of PPEK,then following with the corresponding ring-opening reaction of 3-glycidoxypropyltrimethoxysilane(GPTMS). The structures of the functional PPEK were confirmed by FTIR,~1H NMR,~(29)Si NMR,and UV-vis spectrum.     

How Much Can We Coarse‐Grain while Retaining the Chemical Specificity? A Study of Sulfonated Poly(ether ether ketone)

For mesoscale structural studies of polymers, obtaining maximum level of coarse‐graining that maintains the chemical specificity is highly desirable. Here we present a systematic coarse‐graining study of sulfonated poly(ether ether ketone), sPEEK, and show that a 71:3 coarse‐grained (CG) mapping is the maximum possible map within a CG bead‐spring model. We perform single chain atomistic simulation on the system to collect various structural distributions, against which the CG potentials are optimized using iterative Boltzmann inversion technique. The potentials thus extracted are shown to reproduce the target distributions for larger single chains as well as for multiple chains. The structure at the atomistic level is shown to be preserved when we back‐map the CG system to re‐introduce the atomistic details. By using the same CG mapping for another repeat unit sequence of sPEEK, we show that the nature of the effective interaction at the CG level depends strongly on the polymer sequence and cannot be assumed based on the nature of the corresponding atomistic unit. These CG potentials will be the key to future mesoscopic simulations to study the structure of sPEEK based polymer electrolyte membranes.

     

Inclusion Compounds Formation of Poly(azomethine ether)s and β‐Cyclodextrin

In this study, two poly(azomethine ether)s were synthesized and they can form inclusion compounds (ICs) with β‐cyclodextrin (β‐CD). Fourier transform infrared (FTIR) spectroscopy, ¹H nuclear magnetic resonance spectroscopy (¹H‐NMR), thermogravimetric analysis (TGA), X‐ray diffraction (XRD) have been utilized to observe the formation of polymer‐CD‐ICs. The differentiation in their FTIR spectra may indicate the formation of the inclusion compounds between poly(azomethine ether)s and β‐CD. Compared the ¹H‐NMR of polymer‐CD‐ICs with β‐CD, proton signals belonging to both β‐CD and poly(azomethine ether)s can be found in the spectrum. The chemical shift of the protons H‐3, H‐5 has changed after the formation of inclusion compounds, which is perhaps due to the interaction of these protons with polymers. TGA scans showed the much higher decomposition temperatures observed for two polymer‐CD‐ICs may imply that polymer chains included inside the β‐CD's cavity can greatly improve β‐CD's stabilities. The X‐ray diffraction patterns were confirmed to be the new crystal structures.     

Synthesis of novel polyaryl(ether–ketones) with tert-butyl pendent groups

Linear polyaryl(ether ketones) containing tert-butyl pendent groups were prepared from aromatic hydrocarbons and aromatic diacid chlorides, both classes of monomers containing tert-butyl pendent groups. The polymers were prepared in high yield and high molecular weight by low-temperature precipitation polycondensation in 1,2-dichloroethane. The presence of meta-oriented moieties and bulky pendent groups played a beneficial role with regard to solubility, while the thermal transitions and thermal resistance were not greatly impaired relative to conventional all para-oriented polyaryl(ether–ketones). The current polyaryl(ether–ketones) showed glass transition temperatures in the range 170–240°C and decomposition temperatures, as measured by TGA, of about 500°C. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1251–1256, 1998     

Stereoselective construction of an anti-β-alkoxy ether by Ireland-Claisen rearrangement for medium-ring ether synthesis

The asymmetric synthesis of an acyclic anti-β-alkoxy ether was achieved by the Ireland-Claisen rearrangement of Z-3-alkoxy-2-propenyl glycolate ester, prepared from Garner’s aldehyde, a glycolic acid derivative, and ethynyl N,N-diisopropylcarbamate. The resulting acyclic ether was facilely converted to seven- and eight-membered cyclic ethers via processes involving ring-closing olefin metatheses.     

Synthesis of polyfluoroalkylated glycerol and crown ether

Perfluoroalkylated glycerol (5, 9) and crown ethers (22, 23, 24) were synthesized starting from glycerol. 5 was synthesized by allylation of glycerol 1,2-acetonide followed by perflu-oroalkylation initiated with sodium dithionite, reduction of iodide and hydrolysis in good overall yield and was shown to poccess good surface activities. Glycerol bis-ether (9) was synthesized in a similar way. Allyloxymethyl crown ethers (15, 16, 18) were prepared as key intermediates through multi-step reactions, which were then perfluoroalkylated to give the title crown ethers 22, 23 ,24.     

Poly (ether amide) and silica nanocomposites derived from sol–gel process

The sol–gel derived chemically combined organic–inorganic nanocomposites were synthesized from poly(etheramide) and tetraethoxysilane. Reaction of a mixture of 4-aminophenyl ether and 1,3-phenyldiamine with terephthaloyl chloride (TPC) in dimethylacetamide (DMAc) produced the amide chains. These chains were modified with carbonyl chloride end groups using a slight excess of diacid chloride and were then reacted with aminophenyl trimethoxysilane (APTMOS), where the amine group reacted with carbonyl chloride end groups. Hydrolysis/condensation of tetraethoxysilane (TEOS) and alkoxy groups present in APTMOS developed bonding between the polyamide chains and inorganic silica network generated in situ. By changing the relative proportions of the polymer solution and the amount of TEOS, the composition of hybrid films was varied. Thin hybrid films with various concentrations of silica network obtained after evaporation of the solvent were subjected to mechanical, dynamic mechanical thermal and morphological measurements. The results indicate a gradual increase in the modulus (3.84 GPa) and tensile strength (121 MPa) up to 15-wt.% silica relative to the pure polyamide. The elongation at break point and toughness gradually decrease with addition of silica content. These hybrids were found to be thermally stable up to a temperature of 500 °C. The weight retained above 800 °C was roughly proportional to amount of silica in the matrix. The glass transition temperature and the storage moduli increased with increasing silica concentration. The maximum increase in the T _g value (358 °C) was observed with 15-wt.% silica. Scanning electron micrographs indicated the uniform distribution of silica in the composites with an average particle size ranging from 9 to 47 nm.     

Synthesis of Long-Chain SpirobenzopyransBearing a Monoazacrown ether

Thephotochromicpigmentsinthechloroplastandinthephotoreceptorcellofthevisionsystemhaveamonolayerorganization'.Itisknownthatthemonolayerassembliesfavourtheenergetictransformations.Forthevisionprocess,light-inducedisomerizationofretinallinkedtoopsintrig...     

Synthesis and Crystal Structure of 3,3-Di(acetic ether)-2,4-pentanedione

合成和表征了３，３－二乙酸乙酯基－２，４－戊二酮。得出其为单斜晶系，空间群为Ｃ２／ｃ，ａ＝１４．８６４（２），ｂ＝１０．５６７４（７），ｃ＝９．５０５３（６），β＝１０１．８２５（６）°，υ＝１４６１．１３（２）３，Ｚ＝４，Ｄｘ＝１．２３８ｍｇ／ｍ３，μ＝０．０９８ｍｍ－１，ｆｉｎａｌＲ＝０．０３１４，Ｒｗ２＝０．０８９１     

Dynamic Rheological Characterization of A Thermotropic Liquid Crystalline Poly (aryl ether ketone)

Poly(aryl ether ketone)s (PAEKs) have been widely used as advanced materials in applications because of their excellent thermal stabilities and good chemical resistance1. The high melt viscosity is one of the major drawbacks in processing them. The synthesis of thermotropic liquid crystalline PAEKs has shed light on the solving of this problem2 because they have been proved to have melt viscosities significantly lower in nematic state than those of the isotropic PAEKs and can be melt proce…     

Studies on macrocyclic diterpenoids Ⅴ.Synthesis of(±)-sarcophytol-A benzyl ether

The title compound,sarcophytol-A benzyl ether has been synthesized through 13 stepsby employing acetone and geraniol as starting materials.The key steps in the synthesis weredouble bond migration reaction of allylic alcohols 5 and 6,phase transfer catalytic coupling(PTC)reaction of Ⅱ with 7 and the cyclization reaction of dicarbonyl acyclic precursor inducedby TiCl_3-AlCl_3(3:1)/Zn-Cu system.