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.     

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     

Evolution of Morphology and Properties of Sulfonated Poly（ether ether ketone ketone） Membranes Fabricated via Electrospinning

Sulfonated poly(ether ether ketone ketone)(SPEEKK) membranes with different degrees of sulfonation(DS) were successfully prepared via electrospinning method. The morphology of the resulted membranes varies from nanospheres to nanofibers with increasing the concentration of SPEEKK. The conductivities of the membranes prepared under the same condition increase with the DS increasing. The spherical morphological membranes with a DS of 1.2 show the highest proton conductivity, 0.55 S/cm, which is much higher th...     

Synthesis and Characterization of Poly(ether ether ketone)s with (2,5‐dihydroxy)phenyl Side Group

A new monomer, (2,5‐dimethoxy)phenylhydroquinone (DMPH), was prepared in a two‐step synthetic procedure. One aromatic poly(ether ether ketone)s with 2,5‐dimethoxy phenyl side group (DMP‐PEEK) was synthesized via an aromatic nucleophilic substitution reaction with 4,4′‐difluorobenzophenone (DFB). Poly(ether ether ketone)s with 2,5‐dihydroxy phenyl side group (DHP‐PEEK) was obtained via hydrolysis of methoxy group on the DMP‐PEEK. Both of the high molecular weight polymers could be obtained despite the steric effect of the bulky pendant groups. The two polymers have good solubility at room temperature.     

Sulfonation of Poly(phthalazinone ether sulfone ketone) and Its Application to Isobutene Oligomerization

Ｃｏｎｃｅｎｔｒａｔｅｄｈｏｍｏｇｅｎｅｏｕｓｍｉｎｅｒａｌａｃｉｄｓｈａｖｅｂｅｅｎｗｉｄｅｌｙｕｓｅｄａｓｃａｔａｌｙｓｔｓｉｎｉｎｄｕｓｔｒｉａｌｐｒｏｃｅｓｓｅｓｆｏｒｓｅｖｅｒａｌｄｅｃａｄｅｓ.Ｔｈｅｓｅｃａｔａｌｙｓｔｓａｒｅｃｏｒｒｏｓｉｖｅｔｏｔｈｅａｐｐａｒａｔｕｓ,ａｎｄｔｈｅｒｅａｒｅｌａｒｇｅｖｏｌｕｍｅｓｏｆｃｈｅｍｉ ｃａｌｌｙｒｅａｃｔｉｖｅｗａｓｔｅｓｔｒｅａｍｔｈａｔａｒｅｄｉｆｆｉｃｕｌｔｔｏｄｅａｌｗｉｔｈ[1 ] .Ｉｎｏｒｄｅｒｔｏｓｏｌｖｅｔｈｅｓｅｐｒｏｂ…     

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…     

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.     

Synthesis of Poly(phthalazinone ether ketone) Containing Sodium Sulfonate Groups via Direct Polymerization

Poly (aryl ether ketone)s are a category of high performance engineering plastics which have outstanding thermal, physical and mechanical properties. Poly(aryl ether ketone) with sulfonic groups have received extensive attention for their potential usage as high performance gas dehumidification and ion exchange membrane materials1,2,3. Poly (phthalazinone ether ketone)4, one of poly(aryl ether ketone), shows excellent comprehensive properties and outstanding thermal stability, whose glass tra…     

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.     

Synthesis and Properties of Poly （aryl ether ketone） Copolymers Containing 2,7-Naphthalene Moieties

IntroductionPoly(aryl ether ketone)s are high performance en-gineering plastics with outstanding physical,chemical,thermal and mechanical properties and have been ap-plied to the aerospace industry,the electronic industry,the automobile industry,the petro…     

Fabrication of blend hydrophilic polyamide imide (Torlon®)-sulfonated poly (ether ether ketone) hollow fiber membranes for oily wastewater treatment

Blend hydrophilic polyamide imide (PAI)-sulfonated poly (ether ether keton) (SPEEK) hollow fiber membranes were fabricated for oil-water emulsion separation. The structure and performance of the membranes were examined by FESEM analysis, N₂ permeation, overall porosity, collapsing pressure, water contact angle, pure water flux, molecular weight cutoff (MWCO), and oil rejection tests. By studying ternary phase diagrams of polymer/solvent-additive/water system, the higher phase-inversion rate was confirmed for the solutions prepared at higher PAI/SPEEK ratio. A more open structure with larger finger-likes was observed by increasing PAI/SPEEK ratio. Mean pore size of 81 nm, overall porosity of 79% and water contact angle of 58° were obtained for the improved membrane prepared by PAI/SPEEK ratio of 85/15. Increasing SPEEK ratio resulted in lower mechanical stability in terms of collapsing pressure. Pure water flux of about 2.5 times of the plain PAI membrane was found for the improved membrane. MWCO of 460 kDa was found for the improved blend membrane. From oil rejection test, all the membranes demonstrated an oil rejection of over 95%. The improved membrane showed a lower rate of permeate flux reduction compared to the plain membrane which was related to the smaller fouling possibility. Less fouling resistance of the improved membrane was related to the higher flux recovery ratio (about 92%). For all the membranes, the dominant fouling mechanism was found to be the cake filtration. The improved PAI-SPEEK hollow fiber membranes was found to be practical for ultrafiltration of oily wastewaters.     

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.     

Biodegradability of Poly(ester‐ether) and Poly(ester) Obtained from a Radical Ring‐Opening Polymerization of Cyclic Ketene Acetals

2‐Methylene‐1,3,6‐trioxocane (MTC) and 2‐methylene‐1,3‐dioxepane (MD) were synthesized and polymerized via ring‐opening in the presence of a radical initiator. The obtained poly(ester‐ether) (PMTC) and poly(ester) (PMD) were found to be enzymatically degradable by total organic carbon (TOC) analysis using lipase. The enzymatic degradability of PMTC was higher than that of PMD. PMTC and PMD were also found to be biodegradable with a biological oxygen demand (BOD)‐tester using soil. The degradability of PMTC using soil was also higher than that of PMD. The higher degradability of PMTC by enzyme and soil are thought to be due to its higher hydrophilicity.     

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).     

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.     

Preparation and Properties of Poly（ether ether ketone）/Carbon Nanotube Modified Polypropylene Janus Composite Separator北大核心CSCD

Lithium-ion batteries （LIBs）have attracted wide attention because of their broad prospects in electric vehicles. However,the safety problems and low multiplier performance of the commercial polyolefin separator limit their further development,due to the poor dimensional thermal stability and low electrolyte absorption rate. Poly（ether ether ketone）（PEEK）and carbon nanotube（CNT）are compounded to coat on polypropylene （PP） to prepare Janus composite separator （PP@C） through the phase inversion method. PP@C composite separator does not deform at 180 ℃ for 0. 5 h（only slight deformation）,illustrating excellent thermal stability. The electrolyte absorption rate of PP@C2 is 193. 8%. The electrolyte uptake rate of the PP@C2 composite membrane was 193. 8%,which was 64. 5% higher than the PP membrane,showing a superduper electrolyte permeability. As a result,the specific discharge capacity of LIBs assembled with PP@C2 composite separator is 157. 6 mA·h/g at 0. 2 C and 129. 8 mA·h/g at 2 C,showing good rate performance with the capacity recovery rate of more than 99%. This might be attributed to the ultra-high thermal stability of PEEK,the good affinity of the electrolyte,the high conductivity of CNT,as well as the uniform dispersion of Li+ ,so that the separator can have excellent electrochemical performance while improving safety. © 2022, Science Press (China). All rights reserved.     

Synthesis and Characterization of Poly(ether imide)s Containing m-Methyl and Phthalazinone Moieties

Aromatic polyimides are distinguished for their excellent mechanical and thermal properties in many engineering fields1. However, aromatic polyimides are normally insoluble in common organic solvents, which restricts their applications in some fields. Many efforts have been taken to improve their solubility. Introducing bulky side groups and non-coplanar structure into polymers bone chains is a good way to obtain the polymers with excellent mechanical and thermal properties2. In this paper…     

Synthesis and Thermal Crosslinking Behavior of Poly（aryl ether ketone）s Containing 1,4-Naphthalene Moieties

A new monomer, 1,4-bis(4-fluorobenzoyl) naphthalene (compound 2) was synthesized via a two-step reaction. 1,4-Naphthalenedicarboxylic acid chloride (compound 1) was prepared by using the acyl chlorization reaction of 1,4-naphthalenedicarboxylic acid with thionyl chloride. The Friedel-Crafts acylation of compound 1 with fluorobenzene afforded compound 2 in a 80% yield. The polycondensation of compound 2 with various bisphenols in tetramethylene sulfone(TMS) in the presence of excess potassium carbonate as a condensation reagent was carried out at 210℃ to quantitatively afford the corresponding poly(aryl ether ketone)s (compounds 3-8) containing 1,4-naphthalene moieties. Thermal analyses showed that the polymers have Tg values ranging from 496 to 500 K and are thermally stable in air with initial mass loss above 500℃. These novel polymers exhibited an excellent solubility in organic solvents including NMP, DMAc, and chloroform, etc. In addition, the glass transition temperatures of these polymers increased and the polymers became insoluble in chloroform after treated at 260℃, indicating the occurrence of a thermal crosslinking reaction.     

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.