Synthesis and properties of novel sulfonated polyimides containing binaphthyl groups as proton‐exchange membranes for fuel cells |
| |
Authors: | Yuhan Li Rizhe Jin Zhen Wang Zhiming Cui Wei Xing Lianxun Gao |
| |
Institution: | 1. State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Changchun 130022, People's Republic of China;2. Graduate School, Chinese Academy of Sciences;3. State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Changchun 130022, People's Republic of ChinaState Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Graduate School, Chinese Academy of Sciences, Changchun 130022, People's Republic of China |
| |
Abstract: | A novel sulfonated diamine monomer, 2,2′‐bis(p‐aminophenoxy)‐1,1′‐binaphthyl‐6,6′‐disulfonic acid (BNDADS), was synthesized. A series of sulfonated polyimide copolymers containing 30–80 mol % BNDADS as a hydrophilic component were prepared. The copolymers showed excellent solubility and good film‐forming capability. Atomic force microscopy phase images clearly showed hydrophilic/hydrophobic microphase separation. The relationship between the proton conductivity and degree of sulfonation was examined. The sulfonated polyimide copolymer with 60 mol % BNDADS showed higher proton conductivity (0.0945–0.161 S/cm) at 20–80 °C in liquid water. The membranes exhibited methanol permeability from 9 × 10?8 to 5 × 10?7 cm2/s at 20 °C, which was much lower than that of Nafion (2 × 10?6cm2/s). The copolymers were thermally stable up to 300 °C. The sulfonated polyimide copolymers with 30–60 mol % BNDADS showed reasonable mechanical strength; for example, the maximum tensile strength at break of the sulfonated polyimide copolymer with 40 mol % BNDADS was 80.6 MPa under high moisture conditions. The optimum concentration of BNDADS was found to be 60 mol % from the viewpoint of proton conductivity, methanol permeability, and membrane stability. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 222–231, 2007 |
| |
Keywords: | 2 2′ ‐bis(p‐aminophenoxy)‐1 1′ ‐binaphthyl‐6 6′ ‐disulfonic acid charge transport copolymerization degree of sulfonation polyimides proton conductivity sulfonated polyimides |
|
|