高分子分散劑的合成以及對於鈦酸鋇粉末的分散性質

Abstract

在鈦酸鋇電子陶瓷的製程，要得到穩定性高且分散良好的漿料必須添加分散劑。本篇論文主要是延續本實驗室所合成之分散劑：兩性共聚物PDA [ Poly ( (α-(N,N-dimethyl -N-(3-(β-carboxylate) acrylamino) propyl) ammonium ethanate)-co-acrylamide ) ] 及陰離子型共聚物 PAMC [ Poly (2-Acrylamido-2-methylpropane sulfonic acid-co- Methacrylic acid-co-β-carboxylate (hydroxyl acrylic polyethylester)) ]，探討共聚物中的不同單體比例對於鈦酸鋇水系漿體分散性質的影響，並與分散劑 PMAAN [ Poly (methacrylic acid) ] 比較。 本研究中合成之共聚物以H1-NMR及FTIR確認其結構並利用GPC測定其分子量，使用電位滴定儀測量其單體比例及解離率。 添加共聚物對於鈦酸鋇漿體穩定性的影響，主要研究方法有流變行為、沈降體積及粒徑分佈，並利用表面電位及吸附量等實驗來解釋，另外利用ICP-MASS來測量鈦酸鋇漿體Ba2+的溶出量。實驗結果發現添加共聚物能使鈦酸鋇漿體穩定，而分散效果在添加少量時以PAMC最佳。而由生胚密度、燒結密度、介電常數、介電損失等測試結果顯示，以PDA這一系列效果最佳。另外添加PDA及PAMC均能減少鋇離子的溶出，此因這兩種共聚物具有較多帶負電的官能基可以吸附較多鋇離子。

This study continues the synthesis and application of two copolymers： Ampholytic copolymer, PDA [ Poly ( (α-( N,N-dimethyl-N-( 3- (β-carboxylate ) acrylamino) propyl) ammonium ethanate)-co- acrylamide ) ] and anionic copolymer, PAMC [ Poly (2-Acrylamido- 2-methylpropane sulfonic acid-co-Methacrylic acid-co-(β-carboxylate (hydroxyl acrylic polyethylester))]. The effects of reactant ratio of these two copolymers on the dispersion of BaTiO3 colloids were studies and the results were compared with PMAAN [Poly(methacrylic acid)]. The prepared monomers and copolymers have been confirmed by FT-IR and 1H-NMR, the molecular weight of copolymer was determined by the Gel Permeation Chromatography (GPC), the composition of the copolymer and dissociated ratio was determined by the potentiometric method. The dispersion ability of copolymer on aqueous BaTiO3 slurries was evaluated from viscosity, sedimentation volume, particle size distribution, zeta potential of particles, and adsorption of copolymer onto particles. The amount of leached Ba2+ ion from BaTiO3 to slurry was also measured by ICP-MS. The results indicate that PAMC is most effective in making a stable BaTiO3 slurry.The resulting green parts with PDA show greater density, and the sintered parts have higher dielectric constant, lower dielectric loss, and greater density than those with either PAMC or PMAAN. Besides, both PDA and PAMC causes less dissolved Ba2+ ions into solution. This is because PDA and PAMC have more anionic groups that can interact Ba2+ ion.