酸鹼高分子電解質質子傳遞研究; Proton Transport Properties of Acid-Base Polyelectrolyte

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/6294

Title:	酸鹼高分子電解質質子傳遞研究;Proton Transport Properties of Acid-Base Polyelectrolyte
Authors:	白哲勳;Che-hsun Pai
Contributors:	化學研究所
Keywords:	酸鹼高分子電解質;質子傳遞;acid-base polyelectrolyte;proton transport
Date:	2007-06-28
Issue Date:	2009-09-22 10:17:07 (UTC+8)
Publisher:	國立中央大學圖書館
Abstract:	本研究成功合成所需的鹼性高分子ABPBI，並與三種酸性高分子PVSA、PVPA與PAA混合製成酸鹼混合高分子電解質薄膜。由FT-IR及XRD可知，酸鹼官能基之間產生的作用力使酸鹼高分子之間有好的相容性，而且只要加入少量酸性高分子即會破壞ABPBI本身所形成的規則性排列。在三種酸性高分子中，ABPBI與PVSA之間所形成的作用力最強，甚至有類似鹽類的形成。所有電解質薄膜的熱穩定性都可達200℃以上，可安全的應用在高溫燃料電池中，而且當酸鹼高分子間產生良好的配對，酸鹼官能基的裂解溫度會再提高，使薄膜的熱穩定性增加。各薄膜之乾膜變溫質子導電度測量的數據遵循Arrhenius定律，隨著溫度的上升，質子導電度也隨之增加。在ABPBI-PVPA系統中，比例為50：50之活化能最低。藉由高解析度固態NMR測量的結果可知，當ABPBI與PVPA數量相同時，酸鹼高分子間排列的最緊密，形成了最好的酸鹼配對，因此使得質子在此薄膜中最容易被傳遞。在溼潤的條件下，各薄膜的質子導電度在薄膜開始失水前，皆會隨著溫度的上升而增加，當水分開始揮發後，質子導電度會快速的下降，代表藉由水分子在薄膜中為主要傳遞質子的媒介。由以上數據可知，藉由高分子間類似zip-unzip的運動傳遞質子，與藉由水分子傳遞質子的機制，在各薄膜中都存在。在所有薄膜中，ABPBI與PVPA混合製得之電解質薄膜，無論在濕潤條件或是乾燥條件下，其質子導電度都是最高的，代表imidazole與磷酸根之間的作用力最適合使質子被傳遞。 ABPBI is synthesized successfully in this research. After synthesized , ABPBI mix with three different acid polymers PVSA, PVPA, and PAA to form acid-base polyelectrolyte membranes. FT-IR and XRD data show that the compatibility between acid and base polymers is high because of the acid-base interaction, Besides, after adding small amount of acid polymer in ABPBI, the regular arrangement of ABPBI is destroyed because of the acid-base interaction. The interaction between ABPBI and PVSA is the strongest of all the membranes, even the 50ABPBI-50PVSA is similar to the formation of salt. All the membranes have high thermal stability up to 200℃, it means that the membranes can be used safely in high temperature fuel cells. If acid and base polymers mix well to form an ordered structure, the decomposition temperature of functional groups is increasing, and the thermal stability is higher. Variable temperature conductivity for dry membranes follows the Arrhenius law. With the increase of temperature, the proton conductivity is increasing. In ABPBI-PVPA system, 50：50 ratio shows the lowest proton conductivity. High resolution solid state NMR shows that ABPBI and PVPA form a compact complex when the ratio is 50：50. This result suggests that the proton is more easily to transport in this membrane. In the wet condition, proton conductivity increase with increasing temperature before water loss temperature. When water starts to vaporize, proton conductivity drops quickly, it means water is the major medium to transport proton in membranes. According to the data above, the hopping and vehicle mechanism to transport proton both exist in membranes, and ABPBI-PVPA system shows the highest proton conductivity in dry and wet conditions. It means the interaction between imidazole and phosphonic acid is suitable for proton transport.
Appears in Collections:	[Graduate Institute of Chemistry] Electronic Thesis & Dissertation

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