含氟分枝狀高分子電解質之流變性質

Rheological Properties of Fluoride Branched Polymer Lithium Electrolytes

陳正忠(Zheng-Zhong Chen)

指導教授 ： 鄭國忠

國立臺北科技大學/工程學院/化學工程研究所/碩士(2012年)

摘要

本研究使用雙官能基單體：poly(ethylene glycol) diglycidyl ether (PEGDE)、含胺基之四官能基化合物poly(oxyethylene) diamine (PEDA)，和含氟單官能基化合物glycidyl 2,2,3,3,4,4,5,5-octafluoropentyl ether，經由聚合反應後產生含氟分枝狀聚氧化乙烯高分子，再以此高分子為基質摻混不同比率過氯酸鋰，製備出一系列含氟分枝狀聚氧化乙烯鋰電解質。在本研究中利用凝膠滲透色層分析儀(GPC)測量其分子量，微差掃描熱卡計(DSC)及熱重分析儀(TGA)分析其熱性質與裂解活化能，傅立葉轉換紅外線光譜儀(FT-IR)與核磁共振儀(NMR)鑑定其結構，並使用雙平板式流變儀測量鋰鹽濃度對高分子電解質流變性質之影響。結果發現：其重量平均分子量(Mw)為6900，分佈指數(PDI)為1.4，由滴定方法測其轉化率皆為93%。合成出之含氟分枝狀聚氧化乙烯高分子鋰電解質之玻璃轉移溫度(Tg)將隨鋰鹽濃度的增加而上升，由-59.6上升至-36.8℃。而最大裂解溫度(Tmax)由393下降至287℃。並利用Ozawa法探討高分子鋰電解質之裂解活化能，結果將隨鋰鹽比例的上升而活化能下降的趨勢。導電度則為氧鋰比為15時最佳，在70oC下可以達到5.3-4S/cm。並且將上述之結果與先前實驗室所合成之分枝狀聚氧化乙烯鋰電解質(BP6)做比較。
含鋰鹽之高分子電解質其在零剪切速率( =0)之黏度(η0)隨鋰鹽莫耳比ε增
加而上升，並受溫度影響，可由經驗模式描述。
所合成之含氟分枝狀高分子以及其鋰電解質，在頻率與剪切速率較高時將會呈現剪切稀釋(shear thinning)非牛頓流體現象，可利用Carreau-Yasuda方程式描繪其變化並且計算其鬆弛時間。此外分枝狀聚氧化乙烯高分子鋰電解質之動態儲存模數(G')及損失模數(G")受鋰鹽濃度影響，例如在溫度為40℃頻率為10Hz時，可用方程式描述其關係。

關鍵字

聚氧化乙烯 ； 含氟分枝狀高分子 ； 鋰電解質 ； 流變性質 ； 離子導電度 ； 裂解活化能

並列摘要

The branched polymer derived from poly(ethylene glycol) diglycidyl ether (PEGDE), poly(oxyethylene) diamine(PEDA) and glycidyl,2,2,3,3,4,4,5,5-octafluoropentyl ether as monomer. Polyelectrolytes were prepared by doping the branched polymer with different ratio lithium perchlorate.Using GPC, DSC, TGA, FT-IR and NMR to analyze the characteristics of polyelectrolyte and furthermore we used plate and plate rheometer to analyze the effect of amount of lithium salt on polyelectrolytes. We could get average molecular weight (Mw) was 6900, the distribution index (PDI) was 1.4, and by titration method to calculate the conversion(%) was 93%. It was found that the glass transition temperature of branched polyelectrolytes were about from -59.6 through -36.8oC, which dependent on the amount of lithium salts. And the maximum decomposition temperature was drop from 393 to 287oC. We used Ozawa method to study activation energy of decomposition (Ea) of polyelectrolytes and find activation energy of decomposition will decreased with the amount of lithium was increasing.The best ionic conductivity was 5.3-4S/cm when O/Li=15 at 70oC.And to compare the result with the branched poly(ethylene oxide)-lithium electrolytes(BP6).
The zero shear viscosity(η0) of branched polyelectrolytes was increased with the raise of the lithium salt molar ratio ε, but the zero shear viscosity(η0) was decreased with temperature increasing. Therefore, we proposed experience equation that showing the correlation of viscosity and ε, This mode could fully explain the variation of actual value.

The fluoride branched polymer and it’s lithium polyelectrolyte was showed shear thinning behavior of non-Newtonian fluids at high frequency and shear rate . The relationship between shear rate and shear viscosity of polyelectrolyte could be obtained by Carreau-Yasuda equation. Futhermore, the branched polyelectrolyte’s storage modulus(G') and loss modulus(G") were affected by the lithium salt. According to this result, we found the following equation to explain the relationship between the lithium salt molar ratio and two modulus at 40℃ and frequency at 10 Hz .

並列關鍵字

PEO ； fluoride branched polymer ； lithium polyelectrolyte ； rheology ； ionic conductivity ； activation energy of decomposition

參考文獻

[18] 何永盛，含聚乙烯醚及聚丙烯醚鏈環氧樹脂型高分子電解質之製備及其特性探討，碩士論文，國立成功大學化學研究所，台南，2005。

[29] 梁育豪，含螯合性官能基之膠態高分子電解質之傳導機構的探討，碩士論文，國立成功大學化學工程研究所，台南，2004。

[4] 廖彥程，利用多官能基單體及罩蓋劑合成超分枝高分子，碩士論文，國立台北科技大學化學工程研究所，台北，2008。

[1] 王嘉淳，分枝狀聚氧化乙烯鋰電解質之製備及特性分析，碩士論文，國立台北科技大學化學工程研究所，台北，2010。

[5] 梁仁耀，Dgeba 型環氧樹脂與4,4'-亞甲基雙苯胺合成超分枝高分子，碩士論文，國立台北科技大學化學工程研究所，台北，2009。