添加陰離子型分散劑之鈦酸鋇漿體在不同pH值下的分散行為

吳杏旋

指導教授 ： 許貫中

國立臺灣師範大學/理學院/化學系/碩士(2003年)

摘要

本研究主要是延續實驗室所研發出來的陰離子型分散劑PCOB poly〔(4-carboxyamino-4-oxo-2-butenate)-acrylamide〕，與商用型之甲基丙烯酸鈉鹽PMAA-Na〔sodium salt of poly(methacrylic acid)〕應用於鈦酸鋇粉末探討在不同pH值之分散效果，其中PCOB係以馬來酸酐和氨基甲酸銨鹽反應生成4-羧基氨基-4酮基-2-丁烯酸銨鹽單體，再與丙烯醯胺經自由基聚合反應而得。所得之PCOB以H1-NMR及FTIR確認其結構並利用GPC測定其分子量。
而評估添加分散劑對於鈦酸鋇漿體穩定性的影響，主要方法有黏度，沈降體積，粒徑分佈，並利用高分子之解離率，表面電位，及吸附量來加以解釋，且利用ICP-MASS來測量Ba2+的溶出量，實驗發現添加PCOB能減少鋇離子的溶出，因為PCOB吸附量較PMAA-Na多，且PCOB擁有兩個羧基可以吸附較多鋇離子。由黏度實驗、沈降實驗及粒徑分佈發現添加PCOB能穩定鈦酸鋇漿體，其分散效果可和PMAA-Na相當，且隨著pH值越高，所需要的漿體穩定劑量越少。另外胚體在經過壓胚、燒結後，發現其密度及介電常數均較PMAA-Na高，顯示PCOB確實能有效分散鈦酸鋇漿體。
實驗結果顯示鈦酸鋇漿體在pH=7、9、12時，對於漿體之穩定皆存在一飽和劑量，在此劑量以上，漿體可維持良好之分散，且隨著pH值增加，達到穩定分散所需之飽合劑量越少，即在pH值較高時，僅需較少量之分散劑即可使漿體達到良好之分散。

關鍵字

鈦酸鋇 ； 分散劑 ； pH ； 分散性質

並列摘要

This study continues the research and development of an anionic water-soluble copolymer,poly〔(4-carboxyamino-4-oxo-2-butenate) acrylamide〕(PCOB),which was copmared with PMAA-Na〔sodium salt of poly(methacrylic acid)〕and applied to BaTiO3 powder at different pH to characterise the dispersive ability. PCOB was prepared from 4-carboxyamino- 4-oxo-2-butenate and acrylamide through a free radical copolymerization.4-carboxy
amino-4-oxo-2-butenate was made by reacting maleic anhydride with ammonium carbamate. The chemical structure of PCOB were verified from their H1-NMR and FTIR spectra.,and the molecular weight of PCOB was measured by GPC.
The dispersion ability of PCOB on aqueous BaTiO3 slurries was evaluated from viscosity, sedimentation volume , particle size distribution, and dissussed by using the dissociation of PCOB ,zeta potential of particles, and adsorption of PCOB onto particles.Also, the amount of leached Ba2+ ion from BaTiO3 to slurry was measured.The result shows that PCOB causes less Ba2+ ion dissolved into solution.,because greater amount of PCOB adsorbed on BaTiO3 particles.From the experimental results
of viscosity, sediment volume, and particle size distribution, added PCOB was found to be effective in making a stable BaTiO3 slurry.The dispersion effect is similar to PMAA-Na. The amount of PCOB or PMAA-Na required to stabilize aqueous BaTiO3 suspensions are decreased with increasing pH.
Finally, the sintered parts with PCOB exhibits higher density and dielectric constant than those with PMAA-Na.
Experimental results exhibit BaTiO3 slurries with pH=7,9,12,have a appropriate amount of dispersant for stabilize
aqueous BaTiO3 suspensions,above the point ,slurry can maintain
well dispersion. When the pH value is higher,less amount of dispersant that can making BaTiO3 slurry stable.

並列關鍵字

BaTiO3 ； dispersant ； pH ； properties