Functionalization of poly (aryl ether ether ketone): Synthesis of bromomethylated PEEK and its functionalization

Bromomethyl poly (aryl ether ether ketone) has been prepared from methyl poly (aryl ether ether ketone) (MePEEK) and has been used as the precursor to many forms of functionalized PEEK. MePEEK was brominated directly with bromine. Bromination takes place exclusively at the methyl group. The reaction conditions for bromination have been studied. The bromination level can be controlled by the amount of bromine used, up to 90% of the methyl groups can be brominated to mono-bromo and di-bromo methyl PEEK. Modification reactions have been carried out on the brominated methyl PEEK. The bromomethyl group has been converted to different functional groups, such as ? CH₂OH, ? CH₂OCH₃, ? COOCH₃, ? CH₂CN, ? CH₂COOH ? CH₂OCOCH₃, ? CH₂N⁺H (CH₂CH₃)₂Br^?, ? CH₂N (CH₂CH₃)₂, ? CH₂N⁺ (CH₂CH₃)₃ Br^?. Published 1994 John Wiley & Sons, Inc.     

Synthesis of aromatic polymers via palladium-catalyzed cross-coupling reactions with magnesium,zinc, and tin reagents: A comparison

Difunctional magnesium, zinc, and tin reagents M?C₆H₄?O?C₆H₄?M (M = MgBr, ZnCl, SnBu₃) in the presence of palladium or nickel catalysts undergo cross-coupling polymerizations with aromatic, heteroaromatic, benzylic, and allylic dihalides to give oligomeric and polymeric materials. Tin reagents lead to products of higher molecular weight than Mg and Zn reagents. The reaction is sensitive to the solvent and enhanced by magnesium halides. Increased reaction temperatures lead only to moderate increases in the degree of polymerization and are limited by catalyst decomposition above 200°C. The new poly(ether ketone) and poly(ether sulfone) type polymers prepared show high thermal stability. In contrast to conventional poly(ether sulfones)s, the biphenyl-based sulfone polymers reported here are crystalline. © 1992 John Wiley & Sons, Inc.     

Isothermal melt and cold crystallization kinetics of poly(aryl ether ketone ether ketone ketone)

The isothermal melt and cold crystallization kinetics of poly(aryl ether ketone ether ketone ketone) are investigated by differential scanning calorimetry over two temperature regions. The Avrami equation describes the primary stage of isothermal crystallization kinetics with the exponent n ≈ 2 for both melt and cold crystallization. With the Hoffman–Weeks method, the equilibrium melting point is estimated to be 406 °C. From the spherulitic growth equation proposed by Hoffman and Lauritzen, the nucleation parameter (K_g) of the isothermal melt and cold crystallization is estimated. In addition, the K_g value of the isothermal melt crystallization is compared to those of the other poly(aryl ether ketone)s. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 1992–1997, 2000     

Excess enthalpies of ketone+methyl methylthiomethyl sulfoxide or +dimethyl sulfoxide at 298.15 k

Excess enthalpies of sixteen binary mixtures between one each of methyl methylthiomethyl sulfoxide (MMTSO) and dimethyl sulfoxide (DMSO) and one of ketone {CH₃CO(CH₂)_nCH₃, n=0 to 6 and CH₃COC₆H₅} have been determined at 298.15 K. All the mixtures showed positive excess enthalpies over the whole range of mole fractions. Excess enthalpies of ketone+MMTSO or DMSO increased with increasing the number of methylene radicals in the methyl alkyl ketone molecules. Excess enthalpies of MMTSO+ketone are smaller than those of DMSO+ketone for the same ketone mixtures. The limiting excess partial molar enthalpies of the ketone, H ₁ ^E,∞, in all the mixtures with MMTSO were smaller than those of DMSO. Linear relationships were obtained between limiting excess partial molar enthalpies and the number of methylene groups except 2-propanone.     

Synthesis of copolymers of poly(ether sulfone ether ketone ketone) and poly(ether ketone diphenyl ketone ether ketone ketone) by electrophilic Friedel–Crafts solution polycondensation

A new monomer, 4,4′‐bis(4‐phenoxybenzoyl)diphenyl(BPOBDP), was synthesized via a two‐step synthetic procedure. A series of novel poly(ether sulfone ether ketone ketone)/poly(ether ketone diphenyl ketone ether ketone ketone) copolymers were prepared by electrophilic Friedel–Crafts solution copolycondensation of isophthaloyl chloride (IPC) with a mixture of 4,4′‐diphenoxydiphenylsulfone (DPODPS) and 4,4′‐bis(4‐phenoxybenzoyl)diphenyl (BPOBDP), in the presence of anhydrous aluminum chloride and N‐methylpyrrolidone (NMP) in 1,2‐dichloroethane (DCE). The copolymers with 10–50 mol% DPODPS are semicrystalline and have remarkably increased T_gs over commercially available PEEK and PEKK. The copolymers with 40–50 mol% DPODPS had not only high T_gs of 170–172°C, but also moderate T_ms of 326–333°C, which are extremely suitable for melt processing. These copolymers have tensile strengths of 96.5–108.1 MPa, Young's moduli of 1.98–3.05 GPa, and elongations at break of 13–26% and exhibit excellent thermal stability and good resistance to acidity, alkali, and common organic solvents. Copyright © 2009 John Wiley & Sons, Ltd.     

Synthesis and characterization of the B3-monomer and hyperbranched poly(aryl ether ketone)s

Hyperbranched poly(aryl ether ketone)s were prepared by polymerization of hydroquinone (A₂) and 1,3,5-tris[4-(4-fluorobenzoyl)phenoxy]benzene (B₃). The gelation of hyperbranched poly(aryl ether ketone)s was effectively avoided. Hydroxyl-term inated (HPAEK-OH) and fluoro-terminated (HPAEK-F) hyperbranched poly(aryl ether ketone)s were prepared by using different A₂/B₃ mass ratio. The structure of the B₃ monomer was confirmed by MS, ¹H NMR/IR. The glass transition temperatures of the HPAEK-F and HPAEK-OH are 114°C and 162°C respectively. Thermal stability of HPAEK-F is higher than HPAEK-OH. __________ Translated from Acta Scientianum Naturalium Universitatis Jilinensis, 2005, 5 (in Chinese)     

Sulfonated poly(aryl ether ether ketone ketone)s containing fluorinated moieties as proton exchange membrane materials

A series of sulfonated poly(aryl ether ether ketone ketone)s statistical copolymers with high molecular weights were synthesized via an aromatic nucleophilic substitution polymerization. The sulfonation content (SC), defined as the number of sulfonic acid groups contained in an average repeat unit, could be controlled by the feed ratios of monomers. Flexible and strong membranes in sodium sulfonate form could be prepared by the solution casting method, and readily transformed to their proton forms by treating them in 2 N sulfuric acid. The polymers showed high T_gs, which increased with an increase in SC. Membranes prepared from the present sulfonated poly(ether ether ketone ketone) copolymers containing the hexafluoroisopropylidene moiety (SPEEKK‐6F) and copolymers containing the pendant 3,5‐ditrifluoromethylphenyl moiety (SPEEKK‐6FP) had lower water uptakes and lower swelling ratios in comparison with previously prepared copolymers containing 6F units. All of the polymers possessed proton conductivities higher than 1 × 10^?2 S/cm at room temperature, and proton conductivity values of several polymers were comparable to that of Nafion at high relative humidity. Their thermal stability, oxidative stability, and mechanical properties were also evaluated. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2299–2310, 2006     

Synthesis and characterization of aromatic poly(ether ketone)s containing cyclotriphosphazene units

Bis(4-oxybenzoic acid) tetrakis(phenoxy) cyclotriphosphazene (IUPAC name: 4-[4-(carboxyphenoxy)-2,4,6,6-tetraphenoxy-1,3,5,2λ⁵,4λ⁵,6λ⁵-triazatriphosphinin-2-yl]oxy-benzoic acid) was synthesized and direct polycondensed with diphenylether or 1,4-diphenoxybenzene in Eaton's reagent at the temperature range of 80–120°C for 3 hours to give aromatic poly(ether ketone)s. Polycondensations at 120°C gave polymer of high molecular weight. Incorporation of cyclotriphosphazene groups in the aromatic poly(ether ketone) backbone greatly enhanced the solubility of these polymers in common organic polar solvents. Thermal stabilities by TGA for two polymer samples of polymer series ranged from 390 to 354°C in nitrogen at 10% weight loss and glass transition temperatures (T_g) ranged from 81.4 to 89.6°C by DSC. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1227–1232, 1998     

Structural study on poly(ether ether ketone ketone)-poly(ether biphenyl ether ketone ketone) copolymers

Structures of poly(ether ether ketone ketone)-poly(ether biphenyl ether ketone ketone) copolymers were studied by using small angle X-ray scattering and the one-dimensional electron density correlation function method. The results revealed that structures of the aggregated state of the copolymers depend closely on the biphenyl content (n_b). When n_b = 0.35, invariant Q, long period L, average thickness of crystal lamellae d̄, electron density difference η_c − η_a and degree of crystallinity W_{c, x} assume minimum values.     

Poly(imino imino ether ether ketone ketone) as novel soluble heat-resistant polymer

In this paper, we introduce a novel high-performance polymer, poly(imino imino ether ether ketone ketone), which has been synthesized by the palladium-catalyzed C-N cross coupling reaction of 1,4-bis-(4-bromobenzoyl) benzene and 1,3-bis-(4-aminophenoxy) benzene. The structure of the polymer is characterized by means of ¹H NMR spectroscopy and elemental analysis, and the results show a good agreement with the proposed structure. Compared with traditional poly(ether ether ketone)s, the solubility of the synthesized polymer in common organic solvents was higher; it also exhibited high glass transition temperature (T _g = 176°C) and good thermal stability with high decomposition temperature (T ₅ = 400°C).     

Living cationic polymerization of vinyl ethers with carboxylic acid/tin tetrahalide initiating systems. II. Effects of steric hindrance of carboxylate counteranions

Effects of steric crowding of the substituent of carboxylate counteranions on living cationic polymerization of isobutyl vinyl ether (IBVE) were investigated with the use of two series of carboxylic acids with various carbonyl substituents [RCOOH; R = (aliphatic series) CH₃CH₂, (CH₃)₂CH, (CH₃)₃C; (aromatic series) C₆H₅CH₂, (C₆H₅)₂CH, (C₆H₅)₃C] in conjunction with tin tetrabromide (SnBr₄) and 1,4-dioxane (DO) in toluene at 0°C. The overall polymerization rate increased with increasing the bulkiness of the substituents R in both the series: R = CH₃ (1) ≃ CH₃CH₂ (1) < (CH₃)₂CH (1.76) < (CH₃)₃C (2.31); C₆H₅CH₂ (0.84) < (C₆H₅)₂CH (0.98) < (C₆H₅)₃C (1.74); the values in the parentheses show the relative polymerization rate. In all the polymerizations, the number-average molecular weight (M_n) of the polymers was directly proportional to monomer conversion and in good agreement with the calculated values, assuming that one RCOOH molecule forms one polymer chain. The living nature of these polymerizations was further confirmed by a linear increase in M_n of the polymers upon sequential addition of a fresh monomer feed to the almost completely polymerized reaction mixtures. In the polymerizations with sterically less hindered carboxylic acids [R = CH₃CH₂, (CH₃)₂CH, C₆H₅CH₂, (C₆H₅)₂CH], the molecular weight distribution (MWD) of the polymers was very narrow (M_w/M_n < 1.1) throughout the polymerizations. In contrast, with bulkier substituent-containing counterparts [R = (CH₃)₃C, (C₆H₅)₃C], the polymerizations led to the polymers of relatively broad MWD (M_w/M_n ≅ 1.5 at ca. 100% monomer conversion). The bulky substituents such as (CH₃)₃C and (C₆H₅)₃C may decrease the interconversion rate between a dormant and an active species and increase the time-average concentration of the active growing species. The stereoregularity of the obtained polymers was not changed much with the steric environment of the counteranion (meso: 66–69%). © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2923–2932, 1999     

Synthesis of aromatic poly(ether amide amide ether ketone ketone)s by electrophilic Friedel–Crafts solution polycondensation

A new monomer, N,N′‐bis(4‐phenoxybenzoyl)‐p‐phenylenediamine (BPBPPD), was prepared by the condensation of p‐phenylenediamine with 4‐phenoxybenzoyl chloride in N,N‐dimethylacetamide (DMAc). Novel aromatic poly(ether amide amide ether ketone ketone)s (PEAAEKKs) were synthesized by electrophilic Friedel–Crafts solution copolycondensation of BPBPPD with a mixture of terephthaloyl chloride (TPC) and isophthaloyl chloride (IPC), over a wide range of TPC/IPC molar ratios, in the presence of anhydrous aluminum chloride and N‐methylpyrrolidone (NMP) in 1,2‐dichloroethane (DCE). The influences of reaction conditions on the preparation of polymers were examined. The polymers obtained were characterized by different physico–chemical techniques such as FT‐IR, Differential scanning calorimetry (DSC), Thermogravimetric analysis (TGA), and wide angle X‐ray diffraction (WAXD). The polymers with 70–100 mol% IPC are semicrystalline and have remarkably increased T_gs over commercially available poly(ether ether ketone) (PEEK) and poly(ether ketone ketone) (PEKK) due to the incorporation of amide groups in the main chain. The polymers with 70–80 mol% IPC had not only high T_gs of 209–213°C, but also moderate T_ms of 339–348°C, which are suitable for melt processing. The polymers with 70–80 mol% IPC had tensile strengths of 107.5–109.8 MPa, Young's moduli of 2.53–2.69 GPa, and elongations at break of 9–11% and exhibited high thermal stability and good resistance to organic solvents. Copyright © 2009 John Wiley & Sons, Ltd.     

Glass transition and miscibility in blends of two semicrystalline polymers: Poly(aryl ether ketone) and poly(ether ether ketone)

Binary melt‐blended mixtures of two aryl ether ketone polymers (i.e., a new poly(aryl ether ketone) (code name PK99) and poly(ether ether ketone) (PEEK), have been studied. Polymer miscibility in glassy amorphous (or melt) domains has been demonstrated for the binary blend comprising of two aryl‐ether‐ketone‐type semicrystalline polymers. Composition‐dependent, single T_g was observed within full composition range in the PK99/PEEK blends, and the narrow T_g breadth also suggests that the scale of mixing was fine and uniform. To better resolve any possible overlapping T_g's, physical aging was imposed on a comparison set of blend samples for the purpose of improving detectability of overlapped multiple transitions if existing. The result still showed one single T_g. The relative sharp T_g and lack of cloud point transition suggest that the scale of molecular intermixing is good. Phase homogeneity was further confirmed using optical and scanning electron microscopy. The X‐ray diffractograms suggest that isomorphism does not exist in the PK99/PEEK blends and that the crystal forms of the respective polymers remain distinct and unchanged by the miscibility in the amorphous region. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 1485–1494, 1999     

Synthesis of tert-butyl-substituted poly (ether ketone) by nickel-catalyzed coupling polymerization of aromatic dichloride

tert-Butyl substituted poly (aryl ether ketone)s with relatively high molecular weights were prepared by the Ni-catalyzed polymerization of tert-butyl substituted aromatic dichlorides containing ether ketone unit. These polymers were amorphous and soluble in common organic solvents, such as THF, dichloromethane, and chloroform. De-tert-butylation of the polymer by the treatment of trifluoromethanesulfonic acid in the presence of toluene proceeded smoothly and produced crystalline poly (aryl ether ketone). © 1994 John Wiley & Sons, Inc.     

Preparation of sulfonated poly(phthalazinone ether sulfone ketone) composite nanofiltration membrane

Thin film composite (TFC) membranes were prepared from sulfonated poly(phthalazinone ether sulfone ketone) (SPPESK) as a top layer coated onto poly(phthalazinone ether sulfone ketone) (PPESK) ultrafiltration (UF) support membranes. The effects of different preparation conditions such as the SPPESK concentration, organic additives, solvent, degree of substitution (DS) of SPPEK and curing treatment temperature and time on the membrane performance were studied. The SPPESK concentration in the coating solution was the dominant factor for the rejection and permeation flux. The TFC membranes prepared from glycerol as an organic additive show better performance then those prepared from other additives. The rejection increased and the flux decreased with increasing curing treatment temperatures. The salt rejections of the TFC nanofiltration (NF) membranes increased in the order MgCl₂ < MgSO₄ < NaCl < Na₂SO₄. TFC membranes showed high water flux at low pressure. SPPESK composite membranes rejections for a 1000 mg L⁻¹ Na₂SO₄ feed solution was 82%, and solution flux was 68 L m⁻² h⁻¹ at 0.25 MPa pressure.     

Crystal structure and crystallinity of poly(aryl ether biphenyl ether ketone ketone)

The crystal structure of poly(aryl ether biphenyl ether ketone ketone) (PEDEKK) was determined to comprise a two-chain orthorhombic unit cell with dimensions a = 0.778 nm, b = 0.606 nm and c = 2.375 nm by using wide-angle X-ray diffraction (WAXD). According to the orthorhombic system, the 12 reflections of this polymer were indexed. The crystallite size increases with increasing the crystallization temperature. The results of the degree of crystallinity (W_c,x) calculated from WAXD were compatible with those from density (W_c,d) and calorimetry (W_c,h) measurements.     

Control of molecular weight distribution in polycondensation polymers 2. Poly(ether ketone) synthesis

Synthesis of aromatic poly(ether ketone) (3) with a narrow molecular weight distribution (M_w/M_n) was investigated via polycondensation. M_ns of 3 could be controlled varying the feed ratio of monomer (1) and initiator (2) maintaining relatively narrow M_w/M_ns (<1.3). The kinetics of polycondensation obeyed a first-order relationship between polycondensation time and -(1/[2]₀) ln([1]/[1]₀), and the rate of polycondensation was estimated as 2.57 mol⁻¹ L h⁻¹. MALDI-TOF mass analysis of 3 indicated that polycondensation should proceed via chain growth manner to give 3 having an initiator unit in each chain end.     

Darstellung und stabilität von n,n-disubstituierten β-aminoethyl-magnesiumbromiden; die ersten β-heteroatomsubstituierten grignardverbindungen des typs R2NCH2CH2MgX

R₂NCH₂,CH₂BR (R₂ = Ph₂; Ph, Me; (C₆H₁₁)₂)reacts with highly activated magnesium between ?75 and ?100°c in THF and ether to give the Grignard compounds R₂NCH₂CH₂MgBr, which already decompose between ?90 and?20°c by elimination of ethylene. The thermal stability increases in the sequence R₂ = Ph, Me < Ph₂ < (C₆H₁₁).     

1,5-Migrations of silicon between oxygen centers in silyl β-diketones

A series of acyclic silyl diketonates, (CH₃)₃Si(dik), where dik = dipivaloyl-methanate, diisobutyrylmethanate and hexafluoroacetylacetonate, along with a new series of cyclic acetylacetonates of the type CH₃(-CH₂(CH₂)_xCH₂-)Si(acac), where x = 1, 2, and 3, have been shown to possess enol ether structures in which the acyl group is positioned cis or trans to the silyl group. The ratios of cis to trans configurations in the (CH₃)₃Si(dik) series increase from <0.02 to >50.0 in the order of diketonate substituents CF₃ < CH₃ <i-C₃H₇ < t-C₄H₉. The ratios for the CH₃(-CH₂(CH₂)xCH₂-)Si(acac) compounds increases in the order χ = 1 > 2 > 3. These data are interpreted in terms of incipient pentacoordination of silicon by the carbonyl oxygen atom in the cis isomer. Rates of 1,5-migration of silicon between oxygen centers in the cis isomers have been determined by NMR spectroscopy. The dependence of the rearrangement rates on diketonate substituent and angle strain at silicon indicate that the migration process is better viewed as an internal nucleophilic displacement, rather than a sigmatropic shift. 1,5-Migration in the chiral (C₆H₅CH₂)(CH₃)(C₆H₅)Si derivative of dipivaloylmethanate occurs exclusively with retention of configuration at silicon. The large difference in activation energy for migration and inversion (>18 kcal/mol) precludes the possibility of distinguishing between a stepwise and concerted displacement mechanism.     

Rate constants for the reactions of methylvinyl ketone,methacrolein, methacrylic acid,and acrylic acid with ozone

Rate constants for the reaction of ozone with methylvinyl ketone (H₂C(DOUBLEBOND)CHC(O)CH₃), methacrolein (H₂C(DOUBLEBOND)C(CH₃)CHO), methacrylic acid (H₂C(DOUBLEBOND)C(CH₃)C(O)OH), and acrylic acid (H₂C(DOUBLEBOND)CHC(O)OH) were measured at room temperature (296±2 K) in the presence of a sufficient amount of cyclohexane to scavenge OH-radicals. Results from pseudo-first-order experiments in the presence of excess ozone were found not to be consistent with relative rate measurements. It appeared that the formation of the so-called Criegee-intermediates leads to an enhanced decrease in the concentration of the two organic acids investigated. It is shown that the presence of formic acid, which is known to react efficiently with Criegee-intermediates, diminishes the observed removal rate of the organic acids. The rate constant for the reaction of ozone with the unsaturated carbonyl compounds methylvinyl ketone and methacrolein was found not to be influenced by the addition of formic acid. Rate constants for the reaction of ozone determined in the presence of excess formic acid are (in cm³ molecule⁻¹ s⁻¹): methylvinyl ketone (5.4±0.6)×10⁻¹⁸; methacrolein (1.3±0.14)×10⁻¹⁸; methacrylic acid (4.1±0.4)×10⁻¹⁸; and acrylic acid (0.65±0.13)×10⁻¹⁸. Results are found to be consistent with the Criegee mechanism of the gas-phase ozonolysis. © 1998 John Wiley & Sons, Inc. Int J Chem Kinet 30: 769–776, 1998