Zhiyu Dou

Jilin University, Yung-chi, Jilin Sheng, China

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Publications (5)18.16 Total impact

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    ABSTRACT: Through sol-gel reactions, a series of sulfonated poly(ether ether ketone) (SPEEK)/TiO2 hybrid membranes with various contents of nano-sized TiO2 particles were prepared and characterized. It was found that with the increasing of the TiO2 contents in the hybrid membranes, the water uptake and water retention increased. Meanwhile, the introduction of inorganic particles reduced the methanol permeability. The proton conductivity was enhanced by introduction of hydrophilic inorganic particles into the SPEEK membranes, which might be an effective approach to increase the working temperature of PEM. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
    Journal of Applied Polymer Science 07/2008; 109(2):1057 - 1062. DOI:10.1002/app.25127 · 1.64 Impact Factor
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    ABSTRACT: A series of sulfonated poly(ether ether ketone ketone)s (SPEEKKs) containing tert-butyl groups were synthesized by aromatic nucleophilic substitution reactions. The polymers with high molecular weights showed good solubility and film-forming capabilities. 1H NMR spectra were used to confirm the DS of polymers. The SPEEKK membranes exhibited good thermal and oxidative stabilities and excellent mechanical properties. The proton conductivities of the SPEEKK-40 and SPEEKK-50 membranes were close to that of Nafion 117 at 80 °C under the same testing conditions. The membranes maintained the original proton conductivities even after a boiling water test for 24 h, indicating the excellent hydrolytic stabilities of the membranes. These results demonstrated that the SPEEKK membranes might have very good prospects in proton exchange membranes fuel cell applications.
    Journal of Membrane Science 11/2006; DOI:10.1016/j.memsci.2006.09.016 · 4.91 Impact Factor
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    ABSTRACT: A series of crosslinkable sulfonated poly(ether ether ketone)s (SPEEKs) containing propenyl groups were synthesized by aromatic nucleophilic substitution reactions. 1H NMR spectra were used to confirm the DS of polymers. The resulting polymers showed high molecular weights and good solubility and could be cast into tough membranes. The SPEEK membranes in acid form possessed good thermal stabilities and mechanical properties. The methanol diffusion coefficients ranged from 9.70×10−8 to 4.18×10−7cm2s−1, which were much lower than that of Nafion 117® (2.38×10−6cm2s−1). The proton conductivity of the SPEEK-3 membranes (0.072Scm−1) was close to that of Nafion 117® (0.083Scm−1) at 85°C under the same testing conditions. These results showed that the synthesized materials might have potential applications as the proton exchange membranes for PEMFCs.
    Journal of Power Sources 11/2006; 162(1):51-57. DOI:10.1016/j.jpowsour.2006.06.067 · 5.21 Impact Factor
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    ABSTRACT: To improve the proton conductivity of sulfonated poly(ether ether ketone)s (SPEEK) with low sulfonated degrees, a series of block SPEEK copolymers were prepared by a two-stage one pot process: first the hydrophobic block was prepared with the desired length, then the monomers for the hydrophilic block were added to the first reactive flask to form block copolymers. Membranes were cast from their DMF solutions, and characterized by determining the ion-exchange capacity, water uptake, proton conductivity and mechanical properties. Block-3 with the longer hydrophobic chain shows enhanced performance than the random one in usage for PEM. SAXS was employed to investigate the microstructure effects on the above properties. Larger ionic cluster size and larger proton transport channel in block-3 SPEEK membranes are detected from the result of SAXS. It is believed that this microstructure feature attributes to the enhanced proton conductivity values of block-3 membrane at low IEC.
    Journal of Membrane Science 09/2006; 280(1-2-280):643-650. DOI:10.1016/j.memsci.2006.02.028 · 4.91 Impact Factor
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    ABSTRACT: Summary A novel bis(p-hydroxylphenyl)-1,4,5,8-naphthalenetetracarboxylic diimide (NTDA–OH) monomer was prepared through the condensations of 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA) with p-aminophenol. A series of ternary copolymers derived from NTDA–OH were further synthesized by the nucleophilic substitution reactions. Both the monomer and the ternary copolymers were characterized by FT–IR, 1H NMR, and inductively coupled plasma (ICP). The characterization results showed that, the imide groups were successfully introduced into the prepared monomer. The differential scanning calorimetry (DSC) and the thermal gravimetry analysis (TGA) were further performed on the produced polymers. The thermal stability of the polymer increased with the content of the NTDA–OH increasing.
    Polymer Bulletin 07/2006; 57(3):351-358. DOI:10.1007/s00289-006-0558-7 · 1.49 Impact Factor