本論文利用3,3’-diaminobenzidine和2,2-bis (4-carboxyphenyl)-hexaflouopropane 與5-hydroxyisophthalic acid，成功地合成出含羫基的六氟聚苯咪唑共聚物 (hydroxyl fluorine-containing polybenzimidazole, PBI30OH)，除了利用龐大的側鏈基團提升溶解性外，更含有百分之三十的羫基作為交聯點，添加1,4-phenylene diisocyanate 作為交聯劑，製備出不同交聯程度的共價鍵交聯聚苯咪唑薄膜，並進行機械性質、抗氧化性質、熱性質等測試。研究顯示，交聯薄膜具有穩定的熱性質，隨交聯度的增加，機械性質與抗氧化性質均獲提升。
　　薄膜進行磷酸摻雜後，始具備質子傳導的能力，而磷酸摻雜量隨交聯度的增加略有下降，在160 ℃下，薄膜均有0.02 S/cm以上的質子導電度。在單電池測試部分，分為十四天開關測試與三十天穩定測試。在開關測試 (160 ℃下負載電流200 mA/cm2操作12小時而後關閉燃料降回室溫)，交聯薄膜維持穩定的開路電壓，顯示能防止燃料的穿越。而在三十天穩定測試 (160 ℃下負載電流200 mA/cm2操作720小時)，交聯薄膜輸出電壓衰退速度為0.032 mV/h，優於未交聯薄膜的電壓衰退速度0.184 mV/h，同時能維持較低的磷酸流失量。

In this work, hydroxyl fluorine-containing polybenzimidazole (PBI30OH), a new type of PBI copolymer, was synthesized successfully. The solubility of polymer increased due to the large pendant groups. Thirty percent of hydroxyl groups in PBI can be used this way for crosslinking. Cross-linked membranes, prepared with 1,4-phenylene diisocyanate as crosslinker, exhibited great mechanical properties, oxidative stability and also thermal properties. The acid content of phosphoric acid doped membranes decreased slightly with crosslinking, but all membranes could reach 0.02 S/cm proton conductivity at 160 ℃. Membrane electrode assemblies were fabricated with a size of 4 cm2 and a Pt loading of 1 mg/cm2. Compared with the pristine membrane, the cross-linked membrane showed lower open circuit voltage decay rate and proved more stable in startup and shutdown tests (operated at 160 ℃ with 200 mA/cm2 for 12 h and then kept off for 12 h at room temperature). In long-term durability tests (operated at 160 ℃ with 200 mA/cm2 for 720 h ), the cross-linked membrane showed a lower cell voltage decay rate of 0.032 mV/h and exhausted less phosphoric acid, showing higher stability during operation.

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