燃料电池用侧链型磺化聚砜质子交换膜的性能

Properties of Side Chain Type Sulfonated Polysulfone Proton Exchange Membranes for Fuel Cells

在制备氯甲基化聚砜(CPS)的基础上,以1,2-二羟基苯-3,5-二磺酸钠为试剂,通过亲核取代反应制备一种侧链末端为磺酸基团的侧链型磺化聚砜(PS-BDS),并采用溶液浇注法制备相应的质子交换膜(PEM),研究温度对PEM性能的影响规律。结果表明,由于亲水基团远离疏水聚合物主链,该PEM能够形成亲水微区远离疏水微区的相分离结构,亲水区域对主链的影响较小,该PEM在高磺化度下仍能保持较好的尺寸稳定性,随着温度的升高,PEM的吸水率(WU)、吸水溶胀率(SW)和质子传导率(PC)升高,其中PS-BDS-4(离子交换容量为1.57 mmol/g)在25和85℃时的SW仅为22.1%和55.0%,甲醇的渗透率(DK)仅为10.17×10^-7 cm^2/s,低于商业化的Nafion115(16.8×10^-7 cm^2/s)和Nafion117(23.8×10^-7 cm^2/s),表现出很好的综合性能。

Chloromethylated polysulfones(CPS)was used as the precursors,and side chain type sulfonted polysulfone(PS-BDS)was obtained using disodium 1,2-dihydroxybenzene-3,5-disufonate as nucleophilic reagents.The corresponding proton exchange membranes(PEMs)were produced using solution casting method.The relationship between the temperature and properties of PEMs was studied.Since they have characteristic micro-phase separation structures by locating hydrophilic sulfonic acid group far away from hydrophobic main chain of PS,PEMs have excellent dimensional stability at high water sorption ratio.With the increase of temperature,the proton conductivity,the swelling ratio and the water sorption ratio increase.PS-BDS PEMs have comprehensive size stability and methanol permeability.The swelling ratio of PS-BDS-4 PEM is only 22.1%at 25℃and 55.0%at 85℃.The methanol permeability is 9.94×10^-7 cm^2/s at 25℃,lower than those of commercial Nafion115(16.8×10^-7 cm^2/s)and Nafion117(23.8×10^-7 cm^2/s)PEMs.