Photochemically Cross-linked Poly(aryl ether ketone) Rings

Journal of Polymer Science Part A: Polymer Chemistry, 1997

Isopropyl substituted poly(phenylene ether ether ketone) with a high molecular weight was prepared by nucleophilic substitution reaction of isopropyl-substituted difluoro diaryl ether with hydroquinone. This polymer was amorphous and soluble in common organic solvents, such as THF, chloroform, and cyclohexanone. Thermogravimetry of the polymer showed good thermal stability, indicating that a 10% weight loss of the polymer was observed at 470°C in nitrogen. The glass transition temperature of the polymer was 145"C. The polymer had a broad LJ\Tabsorption band over 250-380 nm. The polymer acted as a photosensitive resist of negative type for tJV radiation. The resist had a sensitivity of 40 mJ/cmz and a contrast of 2.8, when it was developed with DMF at room temperature.

Journal of Photochemistry and Photobiology A: Chemistry, 1990

The new monomers 1-(4-benzylphenyl)-2-propen-lone (4) and l-(4-benzoylphenyl)-2-propen-lone (6) and their homopolymers P4 and P6 and copolymers with styrene P4/S and P6/S were prepared. The polymers exhibit an n-n* band in their UV spectra and vibrationally well-resolved lowtemperature phosphorescence. Both properties are characteristic of photoreactive polyketones. Polymers containing structure 6 show greater near-UV absorption and lower triplet energy in films at 77 K than the photoreactive polyvinylketones. The absorption and emission spectra of the transients, their lifetimes and their quenching by triplet quenchers in benzene at 300 K were determined by laser flash photolysis. Lamp photolysis of the title polymers at 366 nm in benzene results in a decrease in the molecular mass due to the Norrish type II reaction. The quantum yields of main-chain scission are comparable with those of other reactive polyvinylketones (around 0.2). The Stern-Volmer constants based on photolysis and transient quenching indicate the involvement of the long-lived triplet state in the chain scission process. tIssued as NRCC-29468. Presented in part at the 30th Prague Microsymposium on Macromolecules: Polymer Supported Organic Reagents and Catalysts,

Macromolecules, 2005

Highly strained macrocyclic ether-ketones obtained by nickel-catalyzed cyclization of linear precursor oligomers undergo ring-opening polymerization via ether exchange in the presence of nucleophilic initiators such as fluoride or phenoxide anions. Strain enthapies of these macrocycles, from DSC analyses of their exothermic ring-opening polymerization are in the range 50-90 kJ mol-1. Melt-phase polymerization generally affords slightly cross-linked materials, but solution-phase polymerization at high macrocycle concentrations gives fully soluble, high molar mass polymers with inherent viscosities of up to 1.78 dL g-1. Sequence-analysis of the resulting polymers by 13 C NMR shows that alternating or random monomer sequences may be obtained, depending on whether one or both aromatic rings adjacent to the ether linkages are activated toward nucleophilic attack.

Journal of Polymer Science Part A: Polymer Chemistry, 1989

The known polymerization of 4,4'-difluorobenzophenone (DFB) with the &anion of hydroquinone to poly(pheny1ene ether ether ketone) (PEEK) and polymerization of either DFB with the dianion of 4,4'-dihydroxybenzophenone or self polycondensation of the anion of 4-hydroxy-4'-fluoro-benzophenone to poly(pheny1ene ether ketone) (PEK) were studied in N-cyclohexyl-2pyrrolidone (CHP), which is a high-boihg aprotic polar solvent. The formation of high-molecular weight PEEK and PEK in this solvent was very efficient. The reactivity in CHP can be ascribed to effective solvation of metal ions rendering the anion very reactive toward nucleophilic substitution. The polymerization was extended to 4,4'-bis(4-fluorobenzoyl)diphenyl ether and 1,4-bi~4-(4-fluorobenzoyl)phenoxy]benzene to give a high molecular weight polymer with PEK and PEEK repeating units and PEEK respectively. The polymerization of DFB with purified anhydrous sodium sulfide in CHP gave rapidly a high molecular weight poly(pheny1ene ketone sulfide) (PKS). In contrast, diphenyl sulfone (DPS) was not very effective in obtaining such a high molecular weight PKS even with prolonged heating, which suggests the uniqueness of CHP in promoting a high degree of polymerization.

High Performance Polymers, 2004

Macromolecular Chemistry and Physics, 1996

The effects of N‐methyl‐2‐pyrrolidinone (NMP) as solvent on the polymerization reactions of 1,3‐bis(4‐chlorobenzoyl)benzene (1,3‐CBB) and 1,3‐bis(4‐fluorobenzoyl)benzene (1,3‐FBB) with 4,4′‐isopropylidenediphenol (bisphenol‐A) were examined. The failure of these reactions to produce high molecular weight polymers in the presence of anhydrous potassium carbonate is due to dehalogenation of 1,3‐CBB via substitution radical‐nucleophilic unimolecular (SRN1) processes. On the other hand, 1,3‐FBB undergoes nucleophilic aromatic substitution reactions (SNAR) with the carbonate anion at elevated temperatures. However, it is possible to synthesize high molecular weight polymers from 1,3‐FBB and bisphenol‐A in NMP either by first forming the bisphenoxide with stoichiometric amounts of aqueous sodium hydroxide or in the presence of anhydrous potassium carbonate at a lower reaction temperature.

Polymer, 2015

A route for the introduction of functional groups to poly(ether ether ketone) analogues, via a reactivity ratio controlled polycondensation process, has been developed. The reactivity differences, toward nucleophilic aromatic substitution reactions, of the three electrophilic sites in 3,4',5-trifluorobenzophenone, 1, affords the opportunity to prepare functionalized B 2-type monomers in situ, followed by polycondensation with the appropriate bisphenol to prepare the corresponding linear polymer. The reactivity differences in 1 were probed via a combination of 13 C and 19 F NMR spectroscopy along with model reactions using m-cresol as the nucleophile. Reaction of 1 with 1.03 molar equivalents of a series of phenols provided the desired B 2-type monomers in high selectivity. The B 2-type monomers were then converted to the linear polymers by reaction with Bisphenol-A and their structures were confirmed via NMR spectroscopy. The thermal properties were evaluated by a combination of thermogravimetric analysis and differential scanning calorimetry.

Polymer, 2004

Elongated crystalline particles formed as by-products during poly(arylene ether ketone) synthesis by electrophilic precipitationpolycondensation of 4,4 0-diphenoxybenzophenone with terephthaloyl chloride or isophthaloyl chloride, thought previously to be polymerwhiskers, have now been identified as macrocyclic phases. Single crystal X-ray analysis of the needle-like particles formed in the reaction with terephthaloyl chloride, using the microdiffraction technique with synchrotron radiation, revealed that they consist of a macrocylic compound containing ten phenylene units, i.e. the [2 þ 2] cyclic dimer. An analogous structure has also been demonstrated for the corresponding macrocycle derived from the reaction of 4,4 0-diphenoxybenzophenone with isophthaloyl chloride. Chloroform extraction of the products of the two polycondensations dissolved the macrocyclic material (but not the linear polymer), and analysis of the extracts by MALDI-TOF mass spectrometry demonstrated the presence in both cases of homologous families of macrocyclic products. Higher yields of macrocycles were obtained under pseudo-high dilution conditions, enabling the [2 þ 2] cyclodimers from reactions of 4,4 0diphenoxybenzophenone with both terephthaloyl and isophthaloyl chloride to be isolated as pure compounds and fully characterised.

Journal of Polymer Science Part A: Polymer Chemistry, 2005

1,1,1-Tris(4-trimethylsiloxyphenyl)ethane, (silylated THPE), was polycondensed with 2,4-difluoroacetophenone and 2,4-difluorobenzophenone. All polycondensations were performed in N-methylpyrrolidone with K 2 CO 3 as promotor. The feed ratio THPE/difluoroaromat was varied from 1.0:1.3 to 1.0:1.5. Instead of hyperbranched polymers or gels, soluble multicyclic oligo-and polyethers were identified as main reaction products by MALDI-TOF mass spectrometry in all experiments. At feed ratios around 1.0:1.5 multicycles free of functional group were the main products. However, when isomeric a 2 -monomers such as 2,6-difluoroacetophenone, 2,6-difluorobenzophenone (or 2,6-difluorodiphenylsulfone) were used, gelation occurred at feed ratios as low as 1.0:1.1. An explanation of the different cyclization tendencies on the basis of different conformations is discussed. V V C 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6233-6246, 2005

Macromolecular Rapid Communications, 2007