Tribological properties of SiO<sub>2</sub> nanoparticle filled–phthalazine ether sulfone/phthalazine ether ketone (50/50 mol %) copolymer composites

J of Applied Polymer Sci

Xue

Liu

et al. 2005

Self Cite

ABSTRACT:Micrometer-and nanometer-Al 2 O 3 -particlefilled poly(phthalazine ether sulfone ketone) (PPESK) composites with filler volume fractions ranging from 1 to 12.5 vol % were prepared by hot compression molding. We evaluated the tribological behaviors of the PPESK composites with the block-on-ring test rig by sliding PPESK-based composite blocks against a mild carbon steel ring under dry-friction conditions. The effects of different temperatures on the wear rate of the PPESK composites were also investigated with a ball-on-disc test rig. The wear debris and the worn surfaces of the PPESK composites were investigated with scanning electron microscopy, and the structures of the PPESK composites were analyzed with IR spectra. The lowest wear rate, 7.31 ϫ 10 Ϫ6 mm 3 N Ϫ1 m Ϫ1 , was obtained for the composite filled with 1 vol %-nanometer Al 2 O 3 particles.The composite with nanometer particles exhibited a higher friction coefficient (0.58 -0.64) than unfilled PPESK (0.55). The wear rate of 1 vol %-nanometer-Al 2 O 3 -particle-filled PPESK was stable and was lower than that of unfilled PPESK from the ambient temperature to 270°C. We anticipate that 1 vol %-nanometer-Al 2 O 3 -particle-filled PPESK can be used as a good frictional material. We also found that micrometer-Al 2 O 3 -particle-filled PPESK had a lower friction coefficient at a filler volume fraction below 5%. The filling of micrometer Al 2 O 3 particles greatly increased the wear resistance of PPESK under filler volume fractions from 1 to 12.5%.

Section: Introductionmentioning

confidence: 99%

Tribological behavior of micrometer‐ and nanometer‐Al₂O₃‐particle‐filled poly(phthalazine ether sulfone ketone) copolymer composites used as frictional materials

J of Applied Polymer Sci

Xue

Liu

et al. 2005

Self Cite

“…Many efforts have been made to investigate the tribological behaviors of the micrometer particle‐filled polymer composites, and several mechanisms have been suggested to demonstrate the action mechanisms of fillers 8, 9. It should be noticed not much literature is available that has dealt with nanoparticle‐filled polymers for tribological applications;10–12 however, what has been reported seems to show promise. The nanoparticles have the capability of blending well with polymer, which could lead to strengthening of the transfer film.…”

Section: Introductionmentioning

confidence: 99%

The tribological behavior of micrometer and nanometer TiO₂ particle‐filled poly(phthalazine ether sulfone ketone) composites

J of Applied Polymer Sci

Liu

Xue

2004

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Micrometer and nanometer TiO 2 particlefilled poly(phthalazine ether sulfone ketone) (PPESK) composites with various filler volume fractions from 0.5 to 7.5 vol % were prepared by heating compression molding. The friction and wear behaviors of the PPESK composites were evaluated using the block-on-ring test rig by sliding PPESKbased composite blocks against a mild carbon steel ring under dry friction conditions. The wear debris and the worn surfaces of the PPESK composites filled with micrometer and nanometer TiO 2 particles were investigated by using a scanning electron microscope (SEM), while the structures of PPESK composites and wear debris were analyzed with IR spectra. Experimental results show that antiwear properties of the PPESK composites can be improved greatly by filling nanometer TiO 2 particles, and the friction coefficient decreases when the filler volume fraction is below 2.5%, but when the filler volume fraction is above 2.5% the friction coefficient increases gradually with increasing filler volume fraction. In the case of micrometer TiO 2 filler, wear rates increase with increasing filler volume fractions under identical test conditions, and the friction coefficients are less sensitive to the filler volume fraction. It was also found that the wear mechanism of micrometer TiO 2 particle-filled PPESK is mainly severe adhesion and abrasive wear, while that of nanometer TiO 2 particle-filled PPESK is mainly slight abrasive wear. In the former case, there are no transfer film formed on the surface of the counterpart steel, and wear debris are in the form of long and large ribbon. While in the latter case, the wear debris was granule and their size was about 10 m. In case of 1 vol % nanometer TiO 2 particlefilled PPESK composites, the transfer film was fairly thinner and smoother, and the transfer film provided better coverage on the surface of steel ring, while that of 7.5 vol % was thicker and discrete. These account for the different friction and wear behavior of micrometer and nanometer TiO 2 particle-filled PPESK composite.

“…3. The major vibrational structures associated with the QAPPESK membrane 11 are found in all the two samples. The peak at 1240 cm −1 is attributed to the stretching vibration of C-O-C, and 1666 cm −1 is assigned to the stretching vibration of the Ar-CvO.…”

Section: Resultsmentioning

confidence: 91%

“…The peak at 1240 cm −1 is attributed to the stretching vibration of C-O-C, and 1666 cm −1 is assigned to the stretching vibration of the Ar-CvO. 11 For the QAPPESK/H 3 PO 4 membrane, the intense peak at 998 cm −1 and small peak at 880 cm −1 are due to the stretching vibrations of PvO for H 3 PO 4 and P͑OH͒ 2 for H 2 PO 4 − , respectively. 12 This indicates that H 3 PO 4 can be combined with QAPPESK in QAPPESK/H 3 PO 4 composite membrane.…”

Section: Resultsmentioning

confidence: 98%

Quaternized Poly(phthalazinone ether sulfone ketone) Membrane Doped with H3PO4 for High-Temperature PEMFC Operation

Zhang

Electrochemical and Solid-State Letters

2006

A quaternized poly͑phthalazinone ether sulfone ketone͒ ͑QAPPESK͒ membrane doped with H 3 PO 4 was prepared and characterized. Infrared and 31 P NMR spectra indicated that this membrane may have the same mode of conducting proton as polybenzimidazole ͑PBI͒ membrane doped with H 3 PO 4 . The QAPPESK membrane doped with H 3 PO 4 showed high proton conductivity ͑0.072 S/cm at 150°C͒, and good thermostability measured by thermogravimetric analysis. The peak power density of single cell with QAPPESK/H 3 PO 4 composite membrane and operated at 150°C with dry H 2 /O 2 reached 0.85 W/cm 2 . These results show that QAPPESK/H 3 PO 4 composite membrane is promising for high-temperature proton exchange membrane fuel cell ͑PEMFC͒ applications.During recent years, great efforts have been made to develop novel proton-exchange membranes ͑PEM͒ for high-temperature ͑Ͼ120°C͒ proton-exchange membrane fuel cells ͑PEMFCs͒. PEMFCs operated at higher temperature and low relative humidity possess many advantages, including the avoidance of anode catalyst poisoning caused by CO and fuel cell floodin, the significant improvement of the fuel cell efficiency, reduction in the amount of noble metal catalyst due to fast kinetics at high temperature, and humidification of the reactant gasesis not necessary for high temperature PEMFC systems with dry gases. Therefore, the development of PEM, which has satisfactory proton conductivity at higher temperatures and low relative humidity, is of importance in hightemperature PEMFC research and development. [1][2][3] Acid-base complexation represents an effective approach to develop the proton-conducting membranes. Basic polymers can be doped with an amphoteric acid, which acts both as a donor and an acceptor in proton transfer and therefore allows for the proton migration. A number of basic polymers have been investigated for preparing acid-base electrolytes, such as PBI, 4 PEO, 5 and PVA, 6 polyacrylamide ͑PAAM͒, 7 and polyethylenimine ͑PEI͒. 8 However, few polymers can meet the requirements of PEMFCs operated at high temperature ͑Ͼ120°C͒ and low relative humidity.Poly͑phthalazine ether sulfone ketone͒ ͑PPESK͒ has shown superior mechanical strength, chemical resistance and very high glass transition temperature at the temperature range of 263-305°C. 9 In view of this, in this work, the quaternized poly͑phthalazinone ether sulfone ketone͒ ͑QAPPESK͒ membranes doped with H 3 PO 4 were prepared and characterized for PEMFCs operated at high temperature and low relative humidity. ExperimentalMembrane preparation.-QAPPESK membrane ͑40 m thick͒ was prepared according to literature, 10 and the QAPPESK/H 3 PO 4 composite membrane was obtained by immersing the QAPPESK membrane in an 30% H 3 PO 4 solution for 2 h at 25°C. The amounts of H 3 PO 4 absorbed in the membrane were determined by weighing the membrane before and after immersion. The 100 g QAPPESK can absorb about 400 g H 3 PO 4 ·xH 2 O. The reaction of QAPPESK with H 3 PO 4 is shown in Scheme 1.Membrane-electrode assembly.-The membrane-electrodeassembly ͑...