丙烯酸-丙烯酸酯共聚物对钛酸铋水悬浮液性质的影响

研究了丙烯酸－丙烯酸酯共聚物对钛酸铋（Bi4Ti3O12)悬浮液表面化学性质及流变性的影响。结果表明，共聚物的加入使Bi4Ti3O12的等电点向低pH值方向偏移。共聚物在粉体表面的吸附属于物理吸附，其含量的变化可以引起共聚物在粉体表面吸附构型的变化，当共聚物含量＞1．5wt%时，部分高分子脱附。共聚物的加入可以显著改善悬浮液的稳定性，在低共聚物含量和高共聚物含量均可制备稳定的悬浮液，共聚物含量≤1．5wt%时，浆料的稳定通过静电位阻稳定机理来实现，共聚物含量≥2.0wt%时，可能通过空位稳定机理来实现。

Effects of Acrylic acid/Acrylic Ester Copolymer on the Characterization of Bi4Ti3O12 Aqueous Suspensions

An acrylic acid/acrylic ester copolymer was employed as a dispersant for Bi4Ti3O12 aqueous suspensions. Surface chemistry of the suspensions was investigated by several techniques. Zeta-potential measurements showed that the isoelectric point (IEP) of Bi4Ti3O12 was shifted from pH=4 for pure Bi4Ti3O12 to low pH regions in the presence of copolymer. FTIR spectra indicated that copolymers adsorbed on Bi4Ti3O12 surface via physical interaction. The adsorption amount varied with different copolymer content and reached to the maximum values when 1.5wt% (dry mass base) copolymer was added, then decreased because of the deadsorption of the copolymer. The rheology of Bi4Ti3O12 aqueous suspensions was also studied. The results suggested that the stabilization of the suspensions was improved remarkably by the adsorption of the copolymer on Bi4Ti3O12 surface. The stability of the suspensions was attributed to the electrostatic mechanism when the copolymer concentration was less than 1.5wt% and may be the depletion mechanism when the copolymer concentration was higher than 2.0wt%.