聚丙烯酸钠在碳酸镁-水界面吸附的ESR研究

ESR Study on the Adsorption Behavior of Sodium Polyacrylate at the MgCO_3-Water Interface

采用电子自旋共振技术结合自旋标记技术研究了聚丙烯酸钠在碳酸镁表面的吸附构型和分子运动 .结果表明 ,聚丙烯酸钠在碳酸镁上的吸附等温线呈 Langmuir型 ;在低表面覆盖度时 ,聚丙烯酸钠分子固着于碳酸镁表面的吸附链节分数 (p)较大、主要以平躺方式吸附 ,而在高表面覆盖度时 ,p值较小、链环和链尾数增加 .在吸附起始阶段 。

The adsorption configuration and molecular motion behavior of sodium polyacrylate( Na PA ) on the surface of MgCO 3 have been investigated by using the electron spin resonance(ESR) combined with spin labeling technique. The adsorption isotherm of sodium polyacrylate on the MgCO 3 surface was of Langmuir type. The fraction of segments in trains( p ) of the adsorbed Na PA in the case of low surface coverage was greater and mainly in flattened shape, whereas in high surface coverage, the p value was relatively small and mainly in more loop shape. At the beginning of adsorption there occurs an attraction between the positive charges of MgCO 3 surface and polyanions of PA causing the adsorption.