Tang Haolin, Pan Mu, Wang Fang, Shen Pei Kang, Jiang San Ping
J Phys Chem B. 2007 Aug 2;111(30):8684-90. doi: 10.1021/jp073136t. Epub 2007 Jul 12.
A novel method has been proposed to fabricate Nafion/poly(tetrafluoroethylene) (PTFE) composite proton exchange membranes (PEMs) with high durability and high chemical stability. In this method, Nafion ionomers were first converted into the Na(+) form, they were then fixed on PTFE frame micropores, and then the polymer was heat-treated at 270 degrees C. The chemical stability tests of the novel composite PEMs by Fenton's reagent demonstrate the significant improvement in the chemical durability. The Nafion/PTFE composite PEMs also show an excellent physical stability, and its RH-generated stress is 0.6 MPa at 25 RH% and 90 degrees C, substantially smaller than 3.1 MPa for pure Nafion membrane under the same conditions. In an in situ accelerating RH cyclic experiment, the degradation in the open circuit voltage (OCV) of the fuel cell assembled with the novel composite PEMs is 3.3 mV/h, significantly lower than 13.2 mV/h for a fuel cell assembled with the commercial Nafion membrane.
一种制备具有高耐久性和高化学稳定性的Nafion/聚四氟乙烯（PTFE）复合质子交换膜（PEM）的新方法被提出来了。在该方法中，首先将Nafion离聚物转化为Na(+)形式，然后将它们固定在PTFE框架微孔上，接着将聚合物在270℃下进行热处理。通过芬顿试剂对新型复合PEM进行的化学稳定性测试表明其化学耐久性有显著提高。Nafion/PTFE复合PEM还表现出优异的物理稳定性，在25%相对湿度和90℃下其相对湿度产生的应力为0.6MPa，远小于相同条件下纯Nafion膜的3.1MPa。在原位加速相对湿度循环实验中，采用新型复合PEM组装的燃料电池开路电压（OCV）的降解速率为3.3mV/h，显著低于采用商业Nafion膜组装的燃料电池的13.2mV/h。
