陰離子型分散劑分子量對介電陶瓷漿體分散性的影響

鍾子敏

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

本研究主要為合成陰離子型共聚物：聚4-羧基氨基-4-酮基-2-丁烯酸/丙烯醯胺共聚物(PCOB)。在實驗過程中改變起始劑濃度、鏈轉移劑濃度和反應溫度來得到不同分子量的PCOB，探討其對BaTi4O9漿體的分散效果，並和商用分散劑聚甲基丙烯酸銨鹽(PMAAN)做比較。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反應而得。合成之COB單體與PCOB均以H1-NMR和IR光譜確認其結構，並利用GPC測得四種PCOB之重量平均分子量，分別為2.8x105， 1.0x105，6.0x104和1.8x104。
本研究利用黏度法、沉降法、粒徑分佈、表面電位和吸附量等實驗來評估漿體的分散效果。此外，經由壓胚和燒結，測量胚體之燒結密度、生胚密度、介電常數和介電損失。
結果顯示PCOB (Mw=1.8x104)在BaTi4O9漿體的分散效果優於其他分子量，因PCOB (Mw=1.8x104)在BaTi4O9粉體表面有較大的吸附量，使得漿體有較低的黏度與較大的表面電位，而在胚體的測試方面，添加PCOB (Mw=1.8x104)者有較高的生胚密度與燒結密度，表示其粒子分散均勻而堆積緻密。在電性部分，含PCOB (Mw=1.8x104)的胚體可得較高的介電常數與較低的介電損失，因此顯示PCOB (Mw=1.8x104)對BaTi4O9漿體有很好的分散效果。

關鍵字

陰離子共聚物 ； 合成 ； 分散 ； 陶瓷

並列摘要

This study has prepared an anionic copolymer, poly (4-carboxyamino-4 -oxo-2-butene/acrylamide) (PCOB).Experimentally, PCOBs of different molecular weight were prepared by changing the initiator concentra- tion, chain transfer agent concentration, and reaction temperature and their dispersion properties on BaTi4O9 slurries were studied. The results were compared to those with a commercial dispersant, i.e., ammonium salt of polymethylacrylic acid, PMAAN. PCOB was prepared from 4-carboxyamino-4-oxo-2-butene and acrylamide through a free radical copolymerization. 4-carboxyamino-4-oxo-2-butene was made by reacting maleic anhydride with ammonium carbamate. The chemical structures of PCOB have been identified confirmed by H1-NMR and IR spectra, and weight-average molecule weight of 4 PCOBs (Mw=2.8x105、1.0x105、6.0x104 and 1.8x104) were measured by GPC.
The dispersion properties of each dispersant were evaluated by the viscosity, sedimentation volume, particle size distribution, zeta potential ,of the resulting BaTi4O9 slurries. Besides,the sintered density, green density, dielectric constant and dielectric loss of BaTi4O9 compacts were determined.
The results indicate that PCOB (Mw=1.8x104) shows the best dispersion effects on the BaTi4O9 powder in aqueous slurries than PCOB with other molecular weight. For greater amount of PCOB(Mw=1.8x104) was adsorbed on BaTi4O9 particles. The resulting green parts with PCOB (Mw=1.8x104) show greater density, and the sintered parts have higher dielectric constant and lower dielectric loss. Thus, PCOB (Mw=1.8x104) exhibits better dispersion properties than other PCOBs.

並列關鍵字

anionic copolymer ； synthesis ； dispersion ； ceramic

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