Poly(ether ether ketone)s containing benzene pendant in the molecular chain: Synthesis, characterization and optical properties

A series of modified poly(ether ether ketone)s containing different content of benzene pendant group in the molecular chain have been successfully synthesized with 1,1-bis(4-hydroxyphenyl)-1-phenylethane, bisphenol A and 4,4′-difluorobenzophenone by nucleophilic substitution. The inherent viscosities of obtained polymers were in the range of 0.261–0.889 dLg−1. They were found to have high glass transition temperatures (Tg) of 150–168°C and 148–169°C (examined by DSC and DMA, respectively), good thermal stability with 5% weight-loss temperature (T5%) of 439–469°C. The tensile strengths of the obtained polymers were 67.7–86.6 MPa, and the storage modulus was over 0.9 GPa at about 140°C. The modified poly(ether ether ketone)s showed the excellent solubility property, they could be processed by solution method. Additionally, the obtained polymers had good optical transmittance (>70%) at 400 nm, suggesting that they have potential to be applied to the heat-resistant optical films.

New poly(aryl ether ketone)s containing 2,6-diphenylpyridyl units and diphenylphosphinophenyl pendant groups

4-(4-Diphenylphosphino)phenyl-2,6-bis(4-hydroxyphenyl)pyridine, as a new bisphenol monomer, was prepared from 4-(diphenylphosphino)benzaldehyde and 4-hydroxyacetophenone and used in the preparation of several aromatic poly(ether ketone)s (PEKs) containing 2,6-diphenylpyridyl units and diphenylphosphinophenyl pendant groups via a nucleophilic aromatic substitution polycondensation with difluorinated aromatic ketones. The polycondensation proceeded quantitatively in tetramethylene sulfone in the presence of anhydrous potassium carbonate and afforded the polymers with high molecular weights. The resulting PEKs are amorphous and exhibit high glass transition temperatures of 209–255°C and 5% weight loss temperatures of 536–554°C with char yields of 57–62% at 800°C in nitrogen. Their high char yields and good limited oxygen index values ranging from 39 to 43 indicated these polymers exhibited good thermal stability and flame-retardant property. All new PEKs were soluble in common organic solvents such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, and chloroform and could form tough, flexible, and strong films with tensile strengths of 74.6–86.8 MPa, tensile moduli of 2.9–3.6 GPa, and elongations at break of 5–9%.

Effects of potassium titanate whisker and glass fiber on tribological and mechanical properties of PTFE/PEEK blend

Two series of 10% polytetrafluoroethylene (PTFE)/polyether ether ketone (PEEK) composites reinforced with potassium titanate whisker (PTW/PTFE/PEEK) and chopped glass fiber (GF/PTFE/PEEK) were prepared and characterized. We investigated the effects of the additives on thermal stability, tribological properties, mechanical properties, and rheological behavior. The results illustrated that the mechanical properties of 10% PTFE/PEEK blend can be dramatically improved by incorporating either PTW or GF; however, the reinforcing effect of GF was found to be superior. It was found that 1% additive resulted in blends with the best tribological properties. Compared to the unmodified blend, the friction coefficient and wear rate of the 1% PTW blend decreased by 7.2% and 21%, respectively, while the corresponding values of 1% GF blend decreased by 0.66% and 51%, respectively.

Synthesis and characterization of soluble copoly(arylene ether ketone sulfone)s bearing xanthene moiety in the main chain

Several new poly(arylene ether ketone sulfone) (PEKS) copolymers containing xanthene moiety in the main chain were prepared by direct solution polycondensation reaction of 1,4-bis(4-fluorobenzoyl)benzene with varying mole ratios of 9,9-bis(4-hydroxyphenyl)xanthene and 4,4′-sulfonyldiphenol using sulfolane as solvent in the presence of anhydrous potassium carbonate. The introduction of xanthene and sulfone groups into the polymer chain resulted in an improvement in solubility of the polymers in common organic solvents such as N-methyl-2-pyrrolidone, N, N-dimethyl acetamide, sulfolane, pyridine, chloroform, and tetrahydrofuran. Thermal analysis revealed that the copolymers exhibited high glass transition temperatures ( Tgs) of 208–221°C and excellent thermal stability associated with 5% weight loss temperatures ranging from 490°C to 521°C and 62–66% residual weight at 650°C under nitrogen atmosphere. All copolymers were amorphous and their solubility increased with an increase of sulfone content in the polymer backbone, while the Tgs and overall thermal stability appeared to decrease slightly. This new kind of xanthene-containing PEKS copolymers may be considered a good candidate for using as high-performance structural materials.

Synthesis and properties of novel 9,9-diphenyl xanthene-based poly(aryl ether ketone)s with methyl substituents

A new bisphenol, 9,9-bis(4-hydroxy-3-methylphenyl)xanthene, was synthesized via a one-pot, two-step synthetic procedure in good yield and used for polymerization with difluorinated aromatic ketones in tetramethylene sulfone in the presence of anhydrous potassium carbonate to form several aromatic poly(ether ketone)s (PEKs) with 9,9-diphenylxanthene moieties and methyl substituents. The newly synthesized high-molecular-weight PEKs having number-average molecular weights in the range of 20,500–25,600 g mol−1 with the polydispersity index ranging from 1.9 to 2.1 were all amorphous and showed high glass transition temperatures in the range of 194–229.8°C, and the temperatures at the 5% weight loss were in the range of 420–445°C with char yields above 60% at 600°C under nitrogen atmosphere. All new PEKs are soluble in polar aprotic solvents, such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide, chloroform, pyridine, m-cresol, and tetrahydrofuran, and could form transparent, strong, and flexible films with tensile strengths of 66–74 MPa, Young’s moduli of 2.47–2.77 GPa, and elongations at break of 8–14%. In addition, these polymers had high transparency with an ultraviolet–visible absorption cutoff wavelength in the 352–356 nm range and low moisture absorption in the range of 0.41–0.56%.

Synthesis and characterization of new poly(aryl ether ketone)s bearing (4-phenoxyphenyl)triphenylmethane moieties

1,1-Bis(4-hydroxyphenyl)-1-(4-phenoxyphenyl)-1-phenylmethane (BHPPPPM), a new bisphenol monomer, was synthesized with 65% yield from 4-benzoyl diphenyl ether in a one-pot, two-step synthetic procedure. Four new poly(aryl ether ketone)s (PAEKs) bearing (4-phenoxyphenyl)triphenylmethane moieties were prepared from BHPPPPM with four difluorinated aromatic ketones via a nucleophilic substitution reaction. The polycondensation proceeded in tetramethylene sulfone in the presence of anhydrous potassium carbonate and afforded the new PAEKs in nearly quantitative yields with inherent viscosities of 0.60–0.78 dL g−1. The resulting PAEKs having number-average molecular weights in the range of 29,500–34,200 g mol−1 with the polydispersity index ranged from 1.94 to 2.01 are all amorphous and show high glass transition temperatures ranging from 174°C to 196°C, excellent thermal stability, and the temperatures at the 5% weight loss are over 500°C with char yields above 60% at 700°C under nitrogen atmosphere. These new PAEKs are all soluble in polar aprotic solvents such as N-methyl-2-pyrrolidone and N,N′-dimethylacetamide and could also be dissolved in chloroform and tetrahydrofuran. All the polymers formed transparent, strong, and flexible films with tensile strengths of 78–85 MPa, tensile moduli of 1.9–2.4 GPa, and elongations at break of 7–10%.