磺化聚苯醚质子交换膜的制备与性能研究

PREPARATION AND PROPERTIES OF SULFONATED POLY(PHENYLENE OXIDE) PROTON CONDUCTIVE MEMBRANES

以氯磺酸为磺化剂制备了一系列不同磺化度的磺化聚苯醚(SPPO)膜,通过热重-红外联用分析、差示扫描量热分析、含水率测试、力学性能和电导率测试,探讨了SPPO膜作为质子交换膜用于燃料电池的可能性。结果表明,SPPO存在3个阶段的失重,分别归属于吸收的水分、磺酸基团及主链的降解,磺化之后热稳定性虽有所下降,但主链的降解温度基本保持不变,玻璃化转变温度明显升高;SPPO的含水率随着磺化度和温度的增加而增加;膜的拉伸强度则随着磺化度的增加而降低,且膜在湿态时的强度较干态时的要低,但与商业化的Nafion 112膜相比仍具有较高的强度;磺化度为40.1%的SPPO膜在室温下的电导率为1.16×10-2S/cm,与Nafion 112膜为同一数量级。

A series of sulfonated poly（ phenylene oxide） （SPPO） membranes with different sulfonation degrees was prepared using chlorosulfonic acid as a sulfonation agent. The possibilities of application SPPO membranes as electrolyte membranes in fuel cells were investigated by using thermogravimetric analysis （TGA） coupled with Fourier transform infrared （FTIR） spectrometer, differential scanning calorimetry （DSC）, water uptakes, mechanical properties and conductivities testing. Compared with poly（ phenylene oxide） （PPO）, SPPO exhibited three weight loss steps which were attributed to the loss of absorbed moisture, sulfonic groups and polymer backbones, respectively. Sulfonic groups attached to the aromatic ring in the PPO backbone resulted in a degradation of thermal stability, but the main-chain splitting temperature of SPPO was similar to that of pure polymer, and the higher glass transition temperature （Tg） was observed. The water uptake of SPPO increased with sulfonation degree and temperature. An increase of sulfonic groups in the polymer resulted in a decrease in tensile strength. Even though the SPPO membranes were in wet, they still possessed higher mechanical strength than Nation 112 membranes in wet. The conductivity of the SPPO membrane with sulfonation degree equal to 40.1% could reach at 1.16×10^-2 S/cm at ambient temperature, which was comparable to that of Nation 112 membrane.