Adsorption Mechanism of Comb Polymer Dispersants at the Cement/Water Interface

作者：Ran Qianping^*; Somasundaran Ponisseril; Miao Changwen; Liu Jiaping; Wu Shishan; Shen Jian

来源：Journal of Dispersion Science and Technology, 2010, 31(6): 790-798.

DOI：10.1080/01932690903333580

• Adsorption
• cement
• water interface
• comb polymer
• salt effect

Comb polymers are commonly used as dispersants to stabilize highly concentrated cement suspensions. The effectiveness of such polymeric additives to stabilize these suspensions is determined to a large extent by the amount adsorbed. In this study we investigated the adsorption characteristics of various comb dispersant containing different graft densities on surfaces of cement particle. The effect of inorganic salts on their adsorption was also examined in order to elucidate their adsorption mechanism. The results show that the adsorption of comb polymer dispersants on cement surface conforms approximately to Langmuir's adsorption isotherm and the characteristic plateau As and adsorption free energy Gads are largely dependent on the anionic group content of the comb polymers. The As and Gads increase with increasing anionic group content. This information suggests that the adsorption of comb polymers on cement surfaces is dominated by electrostatic interaction between COO-groups on the comb polymers and the positive surface of the cement. This conclusion is supported by effects of inorganics such as calcium and sulfate ions, and diffuse reflectance FTIR spectroscopy. The implication of results for tuning polymers for the required performance in cement manufacture should be noted.

• 出版日期2010
• 单位江苏省建筑科学研究院有限公司; 南京大学