Xigao Jian

Preparation of UF and NF poly (phthalazine ether sulfone ketone) membranes for high temperature application

Abstract The ultrafiltration (UF) and nanofiltration (NF) membranes have been prepared successfully from poly (phthalazine ether sulfone ketone) (PPESK), a proprietary chemical of excellent thermal, chemical and mechanical stability. The effects of PPESK concentration, the type and concentration of additives in the casting solution on membrane permeation flux and rejection were evaluated by using orthogonal array of the design of experiments in separation of polyethyleneglycol (PEG). It is shown that PPESK concentration and the additive in the casting solution is the dominant factor on the rejection and permeation flux, respectively. The membrane performance is consistent and agrees with the theoretical analysis. The membranes were applied in the dye separation with the effects of evaporation time, heat treatment and the type of dye studied. The separation of a variety of dyes of 600–900xa0Da can be accomplished by the PPESK membranes properly prepared. Over 98% dye rejections were obtained for seven typical dyes. The permeation flux increases greatly by raising operation temperature and pressure without significant change of rejection.

Thin film composite (TFC) membranes with improved thermal stability from sulfonated poly(phthalazinone ether sulfone ketone) (SPPESK)

Sulfonated poly(phthalazinone ether sulfone ketone)s (SPPESK) were used to prepare thin film composite (TFC) membranes having increased thermal stability, hydrophilicity and potentially improved fouling-resistance. TFCs were prepared from SPPESK having a degree of sulfonation (DS) 1.5 as the top selective layer coated onto polysulfone (PSF) or poly(phthalazinone ether sulfone ketone)s (PPESK) asymmetric support membranes. At room temperature and 0.25xa0MPa pressure SPPESK/PSF composite membrane rejections for 1000xa0ppm Na2SO4 and NaCl were 91 and 41%, respectively and solution fluxes were 30 and 35xa0kgxa0m−2xa0h−1. A SPPESK/PPESK, TFC membrane had rejections for Na2SO4 and NaCl of 67 and 30%, respectively with similar solution fluxes. Another SPPESK/PPESK membrane had a rejection 63% for 100xa0ppm Clayton Yellow dye (CY, MW=695) while the solution flux was 62xa0kgxa0m−2xa0h−1. When the feed solution temperature increased from 20 to 120xa0°C, solution flux was increased four-fold and the rejection decreased by 14%. The properties of the membrane were almost unchanged from the original values after the membrane was heated at 130xa0°C for 1xa0h and then decreased to 20xa0°C.

Synthesis of novel poly(phthalazinone ether sulfone ketone)s and improvement of their melt flow properties

A series of novel poly(phthalazinone ether sulfone ketone)s was synthesized from bis(4-fluorophenyl) ketone, bis(4-chlorophenyl)sulfone, and 4-(4-hydroxybenzyl)-2,3-phthalazin-1-one through nucleophilic substitution polycondensation. The synthesized polymers exhibited surprisingly high glass transition temperatures and had excellent thermooxidative properties. The melt viscosities of these synthesized polymers are generally too high to be processed by common processing methods because of their very high glass transition temperatures and amorphous microstructure. An attempt was made to reduce their melt viscosities by solution blending the synthesized polymer with two kinds of oligomers: low molecular weight poly(phthalazinone ether sulfone ketone) and commercial poly(ether sulfone). The results proved that the addition of the oligomers to the polymers led to a marked decrease in melt viscosities. Furthermore, no obvious changes were observed in the thermal and mechanical properties of these blends after oligomer additions.

Application of poly(phthalazinone ether sulfone ketone)s to gas membrane separation

A series of poly(phthalazinone ether sulfone ketone) (PPESK) copolymers containing different component ratios of bis(4-fluorodiphenyl) ketone and bis(4-chlorodiphenyl)sulfone with respect to a certain amount of 4-(4-hydroxyphenyl)-2,3-phthalazin-1-one were synthesized by polycondensation. Glass transition temperatures ofthese polymers were adjusted from 263°C to 305°C by changing the ratios of reactants. Gas permeability and selectivity of the dense membranes of the polymers for three kinds of gases (CO 2 , O 2 , and N 2 ) were determined at different temperatures. The result indicated that the membrane of PPESK (S/K = 1/1, mol ratio) had an excellent gas separation property. Permeability of the polymer membranes for CO 2 , O 2 , and N 2 was P CO2 = 4.121 barrier, P O2 = 0.674 barrier, and P N2 = 0.0891 barrier, respectively. Separation factors of α O2 /N and α CO2 /N 2 were 7.6 and 46, respectively. New material was made into a composite membrane with silicone rubber for blocking up leaks and defects on the surface of its nonsymmetrical membrane. As a result of the test, permeability of the composite membrane was J O2 = 7.2 × 10 -6 cm 3 (STP) cm -2 S -1 cm-1 Hg and J N2 = 0.99 × 10 -6 cm 3 (STP) cm -2 S -1 cm -1 Hg, whereas the α O2 /N 2 was still higher than 7. These showed that PPESKs had a bright prospect as the potential membrane material for high-temperature gas separation.

Thermostable ultrafiltration and nanofiltration membranes from sulfonated poly(phthalazinone ether sulfone ketone)

Abstract Modification of poly(phthalazinone ether sulfone ketone) (PPESK) by sulfonation with concentrated or fuming sulfuric acid was carried out in order to prepare thermally stable polymers as membrane materials having increased hydrophilicity and potentially improved fouling-resistance. The sulfonated poly(phthalazinone ether sulfone ketone)s (SPPESK) were fabricated into ultrafiltration (UF) and nanofiltration (NF) asymmetric membranes. The effects of SPPESK concentration and the type and concentration of additives in the casting solution on membrane permeation flux and rejection were evaluated by using an orthogonal array experimental design in the separation of polyethyleneglycol (PEG12000 and PEG2000) and Clayton Yellow (CY, MW 695). One UF membrane formulation type had a 98% rejection rate for PEG12000 and a high pure water flux of 867xa0kgxa0m −2 xa0h −1 . All the NF membranes made in the present study had rejections of ≥96%, and one had a high water flux of 160xa0kgxa0m −2 xa0h −1 . Several of the NF membrane formulation types had ∼90% rejection for CY. When the membranes were operated at higher temperatures (80°C), the rejection rates declined slightly and pure water flux was increased more than two-fold. Rejection and flux values returned to previous values when the membranes were operated at room temperature again. Mono- and divalent salt rejections and fluxes were studied on an additional NF membrane set.

Synthesis and properties of poly(aryl ether sulfone)s containing the phthalazinone moiety

Three series of poly(aryl ether sulfone)s (PAESs) containing the phthalazinone moiety in the polymer backbone were synthesized by solution polycondensation of bis(4-chlorophenyl) sulfone with three commercial bisphenols and 4-(4-hydroxyphenyl)-2,3-phthalazin-1-one. Bisphenol-A, hydroquinone, and bis(4-hydroxyphenyl) sulfone, or bisphenol-S, were selected as the commercial bisphenols for copolymerization. The synthesized polymers exhibited very high glass transition temperatures and excellent thermooxidative properties. They also showed superior mechanical properties and fair rheological properties. The introduction of relatively flexible moieties, such as benzene rings, onto the poly(phthalazinone ether sulfone) (PPES) chain led to a decrease in glass transition temperature with respect to the phthalazinone homopolymer. However, the processability of PPES was improved dramatically by the addition of these commercial bisphenols. The properties of synthesized PAESs can be tailored by changing the molar ratios of bisphenols to phthalazinone monomer.

Synthesis and characterization of sulfonated poly(phthalazinone ether sulfone ketone) for ultrafiltration and nanofiltration membranes

Modification of poly(phthalazinone ether sulfone ketone) (PPESK) by sulfonation with concentrated or fuming sulfuric acid as sulfonation agents was carried out to prepare membrane materials with increased hydrophilicity and potentially increased fouling resistance. Sulfonated PPESK (SPPESK) copolymers, with a degree of sulfonation ranging from 10–300%, were prepared and characterized. Factors affecting the sulfonation reaction were studied, and reaction conditions for the preparation of SPPESK with different degrees of sulfonation were determined. Compared with the properties of PPESK, the hydrophilicity of SPPESK was increased, as shown by a reduced contact angle with water. The glass transition temperature was increased from 278°C (PPESK) to a maximum of 323°C for the highly sulfonated derivative, due to the strong polarity of SO3H and hydrogen bonding. Ultrafiltration membranes prepared with PPESK and SPPESK were compared. For a SPPESK asymmetric membrane, the PEG12000 rejection was 98% and the water flux was 876 kg · m−2 · h−1. SPPESK/PPESK composite nanofiltration membranes were also prepared and were shown to have short-term operational stability up to 120°C.

Anion exchange membranes from brominated poly(aryl ether ketone) containing 3,5-dimethyl phthalazinone moieties for vanadium redox flow batteries

A series of heterocyclic poly(aryl ether ketone)s containing 3,5-dimethyl phthalazinone moieties were synthesized via the copolymerization of 4-(3,5-dimethyl-4-hydroxyphenyl)(2H)-phthalazin-1-one, 4-(4-hydroxyphenyl)(2H)-phthalazin-1-one and 4,4′-difluorobenzophenone. The resulting polymers were brominated with N-bromosuccinimide as the bromination reagent. Brominated poly(phthalazinone ether ketone) (BPPEK) with a degree of substitution in the range of 0.48–0.82 was obtained. Quaternized poly(phthalazinone ether ketone) anion exchange membranes (QBPPEK) were prepared from BPPEK membranes with trimethylamine as the amination reagent. Ion exchange capacity (IEC) values of the QBPPEK membranes were in the range of 0.82–1.53 mmol g−1. Compared with Nafion117 membrane, QBPPEK membranes showed much lower vanadium permeability. Coulombic efficiencies of the vanadium redox flow battery (VRB) with QBPPEK membranes were higher than that with the Nafion117 membrane. The energy efficiency of the VRB increased with an increase in the IEC of the QBPPEK membrane. The energy efficiency of the VRB cell with the QBPPEK membrane having an IEC of 1.53 mmol g−1 was 88%, which was higher than that of the cell with the Nafion117 membrane. During 100 charge–discharge cycles, the QBPPEK anion exchange membrane showed a stable performance.

Poly(phthalazinone ether ketone ketone) anion exchange membranes with pyridinium as ion exchange groups for vanadium redox flow battery applications

Poly(phthalazinone ether ketone ketone) anion exchange membranes with pyridinium as anion exchange groups (PyPPEKK) were prepared by reacting chloromethylated poly(phthalazinone ether ketone ketone) membranes with pyridine in solution. The reaction conditions including diluent solvents, pyridine concentration, reaction time and temperature were investigated. Under the optimized reaction condition, PyPPEKK anion exchange membranes with IEC values in the range of 0.96–1.55 mmol g−1 and water uptake in the range of 10.2–16.5% were obtained. The swelling ratio of PyPPEKK membranes in deionized water and VOSO4 solution were in the range of 3.2–10.6% and 2.5–7.8%, respectively. PyPPEKK membranes showed good chemical stability in VO2+ solution. Notably, PyPPEKK membranes had higher coulombic efficiencies of VRB and much lower vanadium permeability compared with Nafion117 membrane. The energy efficiency of VRB with PyPPEKK membrane reached 83.6% at 80 mA cm−2 while the energy efficiency of VRB with Nafion117 membrane was 80.7% at the same charge–discharge current density. Furthermore, PyPPEKK membrane exhibited good performance in the 100-cycle charge–discharge VRB test.

Preparation and characterization of functionalized carbon nanotubes/poly(phthalazinone ether sulfone ketone)s composites

Multiwalled carbon nanotubes/poly(phthalazinone ether sulfone ketone)s composites have been prepared by in situ polymerization and solution mixing method.The morphology and structure of composites were characterized by scanning electron microscopy and the properties have been investigated.Comparatively,MWNT/PPESK composites prepared by in situ polymerization have more sufficient dispersion and better properties than the solution mixing composites with the same MWNT content.The tensile strength and the Youngs modulus are 107.6MPa and 2.4GPa for the composite with 3wt% MWNT,respectively.And the volume resistivity reaches 106Ω·cm,5% weight loss is improved by about 20℃ from 484-504℃.