Copolymers with cross-linkable pendant carboxylic acid moieties were successfully synthesized via direct copolymerization. Two types of copolymers were prepared. In the first type of copolymers, sulfonic groups were introduced on the biphenol monomers. The second type consisted of a series of copolymers having sulfonic groups on the sulfone monomers. Cross-linking of these copolymers was carried out with the prepared hexafluoro-bisphenol-A epoxy resin (HFB) and membranes were cast on glass plates. Cross-linking caused reduction in excessive fuel cross over, water and methanol uptake without compromising much on the basic membrane properties such as proton conductivity, ion exchange capacity, and selectivity ratio. The proton conductivity increased with the rise in temperature but decreased with further rise in epoxy content. The stability of the cross-linked membranes toward radical oxidation in fuel cell ambiance was revealed from Fenton’s test as cr-6FB-SP-HFB membranes exhibited highest oxidative stability. The improvement in the performance of the cross-linked membranes was found by comparing them with pristine membranes. Atomic force microscopy (AFM) and X-ray diffraction (XRD) analyses confirmed phase separation and amorphous behavior of these membranes. Mechanical properties were determined with the help of a Universal testing machine (UTM). Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analyses revealed excellent thermal stability of these membranes.

通过直接共聚成功地合成了具有可交联的羧酸侧基的共聚物。制备了两种类型的共聚物。在第一类共聚物中，在双酚单体上引入了磺酸基。第二类由在砜单体上具有磺酸基的一系列共聚物组成。用制备的六氟-双酚-A环氧树脂（HFB）进行这些共聚物的交联，然后将膜浇铸在玻璃板上。交联可减少过多的燃料交换，减少水和甲醇的吸收，而不会在基本膜性能（例如质子传导率，离子交换容量和选择性比）上造成很大的影响。质子电导率随温度升高而增加，但随环氧含量的进一步升高而降低。Fenton的测试揭示了交联膜对自由基氧化的稳定性，因为cr-6FB-SP-HFB膜表现出最高的氧化稳定性。通过与原始膜进行比较，发现交联膜的性能有所提高。原子力显微镜（AFM）和X射线衍射（XRD）分析证实了这些膜的相分离和无定形行为。机械性能是在通用测试机（UTM）的帮助下确定的。热重分析（TGA）和差示扫描量热法（DSC）分析显示这些膜具有出色的热稳定性。通过与原始膜进行比较，发现交联膜的性能有所提高。原子力显微镜（AFM）和X射线衍射（XRD）分析证实了这些膜的相分离和无定形行为。机械性能是在通用测试机（UTM）的帮助下确定的。热重分析（TGA）和差示扫描量热法（DSC）分析显示这些膜具有出色的热稳定性。通过与原始膜进行比较，发现交联膜的性能有所提高。原子力显微镜（AFM）和X射线衍射（XRD）分析证实了这些膜的相分离和无定形行为。机械性能是在通用测试机（UTM）的帮助下确定的。热重分析（TGA）和差示扫描量热法（DSC）分析显示这些膜具有出色的热稳定性。