摘要
研究了水溶性阳离子聚氨酯 -脲 -胺乙酸盐 (PUUA)在球形、单分散的纳米二氧化硅水分散液中的吸附行为 .PUUA分子链在稀溶液中呈较舒展的构象 ,分子尺寸小于纳米氧化硅的粒径 .PUUA通过vanderWaals作用力和氢键吸附在氧化硅表面 .在稳定吸附后 ,等温吸附线呈线性上升 ,且没有极限值 .吸附量随纳米氧化硅粒径的增大、胶粒表面电荷的减少和电解质乙酸钠加入量的变化均以相同的斜率线性下降 .PUUA分子量增加 ,吸附量增加 ,且分子量大的PUUA优先吸附于氧化硅胶粒表面 .静电吸引是PUUA吸附至氧化硅溶胶粒表面的主要作用力 .PUUA在氧化硅胶粒上的吸附使体系表观粘度下降 ,敏化作用使体系呈假塑性 。
The adsorption of water-soluble cationic poly (urethane-urea-amine) acetate (PUUA) on colloidal silica as aqueous dispersion was studied. The results indicated that the conformation of the PUUA chains was in stretched conformation in dilute solution, and the average molecular size was smaller than the diameter of silica particles. The adsorption of PUUA onto the colloidal silica was attributed to van der Waals' and hydrogen bonding forces. The adsorption isotherms revealed that, after stable adsorption on the surface of silica particle, the adsorption amount of PUUA linearly increased, moreover, there was not an ultimate saturated adsorption. The apparent adsorption was linearly, by the same slope, decreased with increase of the colloidal silica size, falling of the surface charges of silica, and increase of the amount of sodium acetate added. Furthermore, the adsorption was ascended with increasing molecular weight of PUUA, and the adsorption of the large molecules was prior to the small molecules of PUUA. The electrostatic attraction was the predominant effect on the adsorption of the PUUA from water onto the colloidal silica. The apparent viscosity of the dispersion was decreased by the adsorption of the PUUA-E onto the colloidal silica. ne sensitivity of the dispersions showed pseudoplastic flow, while the protection of the dispersions displayed dilatancy.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2003年第10期1543-1549,共7页
Acta Chimica Sinica
基金
国家自然科学基金(No .50 0 730 0 5)资助项目 .
