Synthesis And Properties Of The Novel Poly(Arylene Ether Sulfone-ketone) Ionomers With Designed Microphase

Poly(arylene ether sulfone-ketone) ionomers containing designed fluorene-phthalazinoneamphiphilic blocks, which have micro-phase separation structure, were successfully preparedby the synthesis process of the "two-pot two-step" method by adjusting the monomer ratiobased on the low-cost chemical raw materials. To best of our knowledge, this work has neverbeen published. The properties of the ionomers materials were tested. Details are as follows:A series of block ionomers containing sulfonated poly(phthalazinone ether ketone)hydrophilic segments and poly(fluorene ether sulfone) hydrophobic segments weresynthesized via two-pot two-step nucleophilic polycondensation. Bis(4-chlorophenyl) sulfoneand9,9-bis(4-hydroxyphenyl) fluorene (BHF) were used as comonomers for hydrophobicblocks. Bisphthalazinone containing6F-BPA moiety and sulfonated4,4-difluorobenzophenone (SDFBP) were used to synthesize hydrophilic blocks. Ionomerswith different segment sizes were synthesized by adjusting the molar ratios andprepolymerization and polycondensation. The structure of the ionomers was characterized by1H-NMR and FTIR. The spectra and data indicated that these polymers were in accordancewith designed backbone structure well. The TGA measurements of the polymers demonstratedthat the so-made polymers exhibited good thermal stabilities with5%weight loss temperatureover250℃. The water uptakes of the copolymers with varying sized blocks were moderate.Moreover, these copolymers membranes demonstrated good alcohol resistance and resistanceto methanol permeability, excellent oxidation resistance and hydrolytic stability, as well as theappropriate proton conductivity. The proton conductivity of the membranes at80oC showed adoubling trend from the polymers at30℃. Especially, polymer8e gave the protonconductivity of1.83×10^-3S/cm at80℃. The results of AFM determination demonstrated thatthe membranes showed an obvious microphase separation structure and the diameter ratio ofthe hydrophilic region and hydrophobic region increased with the growth of and resulting inmore contiguous proton transport channel. The response of hydrophobic and hydrophilicvaried with the segment sizes. When the segment sizes were short, hydrophilicity wasdominant, the ionomer membrane demonstrated continuous hydrophobic region and isolatedhydrophilic region. Hydrophilicity strengthened with increased segment sizes. The wet membranes exhibited phase invert. The ionomers membrane demonstrated continuoushydrophilic region and isolated hydrophobic region. Thus it resulted in more continuousproton conductive channels.In addition, a series of block ionomers with various sizes of poly(phthalazinone etherketone) hydrophilic segments and poly(fluorene ether sulfone) hydrophobic segments weresynthesized via two-pot two-step nucleophilic polycondensation. Bis(4-chlorophenyl) sulfoneand9,9-bis(4-hydroxyphenyl) fluorene (BHF) were used as comonomers for hydrophobicblocks. Bisphthalazinone containing biphenyl moiety and sulfonated4,4-difluorobenzophenone (SDFBP) were used to synthesize hydrophilic blocks. Thesepolymers were in accordance with designed backbone structure well and exhibited goodthermal stabilities. Furthermore, the so-made polymers membrane demonstrated excellentproton conductivity, high hydrolytic stability and good mechanical properties, as well as theappropriate water uptakes and swelling ratio. With the increase of the ratio of hydrophilicsegments in the proportion of chain segments, alcohol uptakes increased and oxidationresistance decreased. The proton conductivity increased with increasing temperature. Theproton conductivity of the membranes at80℃was close to or higher than that of Nafion117at30℃. Especially, the proton conductivity of the polymer12d reached5.01×10-3S/cmat100℃. The XRD results showed that these ionomers had crystal phase. The AFM resultsshowed that the wet ionomers membranes exhibited clear hydrophilic/hydrophobicmicrophase separation structure and phase invert. The ionomers membranes demonstratedcontinuous hydrophilic region and small size isolated hydrophobic region. The hydrophilicregion sizes increased with increasing ratios of hydrophilic segment to hydrophobic segment.And the ionomers membranes were swelling easier and formed big size proton conductivechannels.To sum it up, the novel poly(arylene ether sulfone-ketone) ionomers are promisingproton exchange membrane materials used in high temperature proton exchange membranefuel cell.