添加高分子電解質對於鈦酸鋇粉末分散性質的影響

Effects of Addition of Polyelectrolytes on the Dispersion of Barium Titanate

郭明仁(Ming-Ren Kuo)

指導教授 ： 李嘉甄

國立臺北科技大學/工程學院/材料科學與工程研究所/碩士(2010年)

摘要

積層陶瓷電容器為陶瓷電容的一種，其結構主要是介電陶瓷粉與內外電極所組成。鈦酸鋇為積層陶瓷電容器之關鍵原料，其具有優異的介電常數。近幾年來，由於環保意識的抬頭，研究方向逐漸朝向水系鈦酸鋇漿料發展。然而鈦酸鋇在水中不易分散，為了防止粒子的聚集，典型的方法則是採用高分子電解質做為分散劑。在商業分散劑中，陰離子型分散劑-聚丙烯酸（PAA）的高分子電解質常被用於水系鈦酸鋇，主要是因為丙烯酸共聚合物的羧酸官能基能吸附在鈦酸鋇表面且充分的達到靜電斥力而達到良好的分散。本次研究的重點是聚羧酸分散劑的分子結構對水系鈦酸鋇的影響，使用三種不同分子結構的聚羧酸分散劑，聚丙烯酸PAA（Poly(acrylic acid)）；聚丙烯酸共馬來酸PAMA（Poly(acrylic acid-co-maleic acid)）；聚衣康酸PIA（Poly(itaconic acid)）。以13C-NMR及FT-IR確認自行合成之分散劑-PIA的結構及GPC測定其分子量。使用電位滴定法測量分散劑解離率及吸附量，利用zeta電位、流變、沈降試驗等實驗結果，來解釋不同之分子結構與羧酸密度對水系鈦酸鋇漿料分散性的影響。

關鍵字

鈦酸鋇 ； 高分子電解質 ； 分散

並列摘要

Barium titanate is the key material of Mutilayer Ceramic Capacitor, which has excellent dielectric constant. In recent years, the research has been concentrated on the aqeous barium titanate slurry due to the consideration for environmental consistency. However, commercial barium titanate is not easy to be dispersed in water, and using dispersants is the most popular method to prevent its agglomerations. Among dispersants, the anionic polyelectrolyte, ammonium salt of poly（acrylic acid）-PAA-NH4, is efficient and commonly used because that its dissociated carboxyl group can anchor on the surface of barium titanate to provide electrosteric hindrance between particles. This investigation studies the effect of conformation and chemical structure of dispersants on their dispersion efficiency for BaTiO3. The dispersants studied in this investigation include Poly(acrylic acid) （PAA）, Poly(acrylic acid-co-maleic acid)（PAMA） and Poly(itaconic acid)（PIA）.Based on the measuring results of zeta potential, rheology, FT-IR and semdimentation, it is known that the PAA and PAMA are effective dispersants for the dispersion of BaTiO3 in aqeous suspensions due to their beneficial conformations for preventing agglomeration of particles.

並列關鍵字

Barium titanate ； polyelectrolyte ； dispersion

參考文獻

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