本研究藉由四種已由本實驗室標定的新型四胺單體4,4',5,5'-tetraamino-2,2'-dimethylbiphenyl (5)、4,4',5,5'-tetraamino-2,2'-bis(trifluoromethoxy)biphenyl (10)、4,4',5,5'- tetraamino-2,2'- bis(trifluoromethyl)biphenyl(14)及4,4'-oxy-bis[3-(trifluoromethyl)-1,6-benzendiamine](21)以Eaton’s reagent為溶劑，分別與4,4'-oxybis(benzoic acid)進行縮合聚合反應，聚合出側基含有甲基的P1、側基含─OCF3基團之P2及側基含三氟甲基之聚苯并咪唑P3及P4。P1、P2、P3及P4之固有黏度分別為3.2、2.9、1.6及1.0 dL/g，皆能全溶於室溫強酸中，因此能使用MSA作為溶劑，製備成具有韌性的PBI薄膜。在氮氣條件下，P1、P2、P3及P4之5 % (Td5 %)熱重損失之熱裂解溫度分別為413、516、396 ℃及390 ℃；而10 % (Td10 %)熱重損失之熱裂解溫度467、546、449及489 ℃，在800 ℃下的殘餘重量則分別為76、58、67及64 %，皆展現出好的耐熱安定性。氧化安定性是藉由將P1、P2、P3及P4薄膜浸泡於68 ℃ Fenton溶劑中隨時間定點量測殘餘量。在浸泡216小時後，P1、P2、P3及P4殘餘量分別為89.5 %、93.7 %、63.0 %及51.2 %。P1、P2、P3及P4薄膜在室溫下浸泡於不同濃度的磷酸溶液(P1、P2為85、80、75 %，P3為75、70、65 %，P4為65、60、55 %)，其磷酸摻雜量P1分別為204、160、143%，P2分別為142、101、92%，P3分別為393、168、146%，P4則分別為328、148、128 %。在飽和磷酸摻雜下，P1、P2、P3及P4薄膜其拉伸應力分別為24.4、17.0、10.2及11.6 MPa。P1、P2、P3及P4薄膜在未摻雜磷酸，透過SEM觀察其薄膜表面及橫截面，皆顯示出緻密無孔洞。最後將摻雜磷酸P1、P2、P3及P4薄膜在160 ℃下進行質子傳導度測試。P1在摻雜204 %的磷酸下具有4.72× 10-2 S/cm的質子傳導度；P2在摻雜142 %的磷酸下具有1.17× 10-2 S/cm的質子傳導度；P3在摻雜228 %的磷酸下具有4.11× 10-2 S/cm的質子傳導度；P4在摻雜295 %的磷酸下具有11.5 × 10-2 S/cm的質子傳導度，相較於商用m-PBI的傳導度4.31 × 10-2 S/cm高上許多，證實P1、P2、P3及P4薄膜聚苯并咪唑能被應用於質子交換膜燃料電池當中。

Novel PBI, P1, P2, P3 and P4 were prepared from 4,4'-oxybis(benzoic acid) (OBA) and 4,4',5,5'-tetraamino-2,2'-dimethylbiphenyl (5), 4,4',5,5'-tetraamino-2,2'-bis(trifluoromethoxy)biphenyl (10), 4,4',5,5'- tetraamino-2,2'- bis(trifluoromethyl)biphenyl(14), and 4,4'-oxy-bis[3-(trifluoromethyl)-1,6-benzendiamine](21) by using Eaton’s reagent as solvent, respectively. The structures of P1, P2, P3 and P4 were characterized by FT-IR and 1H-NMR. The inherent viscosity of P1, P2, P3 and P4, measured in methanesulfonic acid at 35 ℃ and 0.2 g/dL, were 3.2, 2.9, 1.6 and 1.0 dL/g, respectively. P1, P2, P3 and P4 could be prepared as transparent, flexible, and tough membrane by solution casting. The decomposition temperature at 5 % weight loss (T d5 %) of P1, P2, P3 and P4 were 413, 516, 396 ℃ and 390 ℃, respectively, and the residual weight of P1, P2, P3 and P4 at 800 ℃ were 76, 58, 67 and 64 %, exhibiting outstanding thermal stability. The oxidative stability of P1, P2, P3 and P4 membranes were evaluated by Fenton test. The residual weight of P1, P2, P3 and P4 were 89.5 %, 93.7 %, 63.0 % and 51.2 % after 216 hours of Fenton test. When P1, P2, P3 and P4 membrane were immersed in different concentrations of phosphoric acid at room temperature, we could obtain P1, P2, P3 and P4 membrane with the maximum phosphoric acid uptake (PU, %) about 204, 142, 393, and 328 %, respectively. The proton conductivity of P1, P2, P3 and P4 were 4.72× 10-2, 1.17× 10-2, 4.11× 10-2, and 11.5 × 10-2 S/cm at 160 ℃ when PU were 204, 142, 228 and 295 %, respectively. It shows that P1, P2, P3 and P4 are promising proton exchange membranes for HT-PEMFC applications.

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