| Summary: | 碩士 === 國立臺灣師範大學 === 化學研究所 === 91 === Abstract
This study continues the research and development of an amphibious water-soluble copolymer, i.e., poly(α-(N,N-dimethyl-N-(3-(β-carboxylate) acrylamino) propyl) ammonium ethanate)/acrylamide (PDAE), as a new dispersant for aqueous BaTiO3 slurries. PDAE was prepared from α-(N,N-dimethyl-N-(3-(β-carboxylate) acrylamino) propyl) ammonium ethanate (DAE) and acrylamide through free radical polymerization. DAE was prepared from reacting β-carboxylate-N-(3-dimethyl-amino- propyl) acrylamide with dimethyl-1,3-propylene diamine. The prepared DAE and PDAE were verified from their H-NMR spectra, and the molecular weight of PDAE was measured by GPC.
The dispersing effectiveness of PDAE on aqueous BaTiO3 slurries were examined and discussed from the resulting viscosity, sedimentation volume, particle size distribution of pastes, and the zeta-potential of BaTiO3 particles. Besides, the concentration of dissoluted Ba2+ in the slurries, the density and electrical properties of sintered compacts were also measured. The results indicate that PDAE (weight-average molecular weight = 4 x 10 5) shows good dispersing ability because this copolymer can reduce the slurry viscosity, make the slurry more stable, and result in smaller particle size. Compared to a commercial dispersant, sodium salt of polymethylacrylic acid (PMAA-Na), it is as effective or even better in preparing stabilized suspensions. More importantly, PDAE can reduce the leached Ba2+ concentration. This is related to the chemical nature and adsorption behavior of this copolymer. Consequently, the BaTiO3 slurries with PDAE shows higher sintered density, higher dielectric constant, and lower dielectric loss than those with PMAA-Na.
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