| Fuel cells are devices that directly convert the chemical energy of reactants (fuels and oxidants) into low voltage D.C. electricity via electrochemical reactions. They are received widely attention due to their high efficiencies, high specific energy densities and ability to provide the necessary power.Proton exchange membrane fuel cells as one type of fuel cells (PEMFC) have widely investigated as a promising new power sources for vehicles and portable devices, due to their low emissions and high conversion efficiencyProton exchange membrane, as proton conductive material is a key component of the PEMFC for transferring protons from the anode to cathode as well as providing a barrier to the fuel gas cross-leaks between the electrodes. The membranes traditionally used in PEMFC are perfluorosulfonic polymers such as Dupont Nafion?. Although they show superior performance in fuel cells operating at moderate temperatures (<90oC) and high relative humidity with pure hydrogen as fuel, the high cost, low conductivity at low humidity or high temperature and high methanol permeability of Nafion? have limited their usages. Hence alternative proton exchange membrane materials are being sought. Usually there are two ways to solve the problem:(1): To decrease the content of perfluoroionomers to decrease their cost by preparing composite membranes.(2): To explore high performance proton exchange membranes materials, such as sulfoanted polyacromatic polymers.Sulfoanted poly(aryl ether ketone (PAEK) are attracted by most investigators as having low cost and simple way of polymerization,but the structure limitations made them have low conductivity at low Ds and high swelling ratio at high Ds,and have no phase -separation like that of Nifan.In this thesis, we have introduced the long side chain into poly(aryl ether ketone (PAEK) to prepare high performance proton exchange membranes. Further we have characterized the structures and the properties of the resulted membranes in detail. The study showed that: sulfonated poly(aryl ether ketone) (SPAEK) polymers show very good prospective usages in PEMFC.In chapter 2, we have successfully prepared novel monomer,Bisp,which having different long side chain,by reaction of bisphenol with ketone,HPA as a catalyst,and discused the method of preparation of thses monomers.the results of elemental analysis and 1H NMR show that they have high alternative in–p- position and strcture we desired.In chapter 3, the novel PEEKs with long side chain are prepared by reacting the new monomers with 4,4'- difluorobenzophenone ,The results of DSC and TGA show that the new prepared PEEKs have good thermal properties ,Tg decreses with the increse of lengh of side chain ,from 163 to 39. Symmetry of long side chain is another important factor to decrese the Tg, they have good mechnical and soluble properties.although the temperature of Td5% are slightly lower .In chapter4, the novel SPEEKs with long side chain and different Ds are prepared by reacting the new monomers with 4,4'- difluorobenzophenone and Sodium 5,5'- carbonyl bis(2-fluorobenzene sulfonate),the strcture are determined by FT-IR and 1H NMR, the themal and mechnial properties are chacterized by DSC and TGA,the membrance properties ,i.e wateruptake,Ds,IEC,methanol permeability,proton condctivity are disscused , morphologe of the SPEEKs are investigated by transmission electron microscope TEM as to obtain the message of micro- phases.Similar to the results of prevous work,the membrance properties depend closesly on the Ds,but the mechnical strength are strong enough even at high Ds ,and have much lower methanol permeability than that of Nafion ,even much lower than most of the SPEEKs which have no side chainsAll the results show that: more clearly tendency of forming phase-separated structures will be seen with the increasing of Ds of SPAEK membranes. The membranes with high Ds will provide much larger and more continuous transport channels for protons.
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