聚羧酸减水剂在水泥颗粒表面的吸附行为研究

关键字：聚羧酸,减水剂,水泥,颗粒,表面,吸附

（1.江苏苏博特新材料股份有限公司，江苏 南京  211103；2．高性能土木工程材料国家重点实验室，江苏 南京  211103）
 

    摘要：通过研究真实水灰比条件下聚羧酸减水剂（PC）模型分子在水泥颗粒表面的吸附动力学行为和等温吸附行为，为筛选特殊分散速度的PC提供理论指导。结果表明，PC在水泥颗粒或其水化产物表面的吸附动力学行为遵循准二级吸附动力学。对于同一模型分子来说，吸附速率常数k1值随着掺量增加而降低，饱和吸附量Qs随着掺量增加而增加。PC在水泥颗粒或其水化产物表面的吸附达到平衡时为典型的Langmuir单分子层吸附。对于给定的单体种类，仅仅调整侧链密度、分子质量等参数，对Langmuir平衡常数k2的影响不大。
    关键词：聚羧酸减水剂；吸附动力学；准二级动力学；吸附等温线；Langmuir等温方程
    中图分类号：TU528.042.2        文献标识码：A        文章编号：1001-702X（2017）11-0013-04
 

Adsorption behavior of polycarboxylate superplascticizer on cement particle surfaces
WANG Xiumei1，YANG Yong1，SHU Xin1，ZHANG Xia1，RAN Qianping1，2
（1.Jiangsu Sobute New Materials Co. Ltd.，Nanjing 211103，China；
2.State Key Laboratory of High Performance Civil Engineering Materials，Nanjing 211103，China）

    Abstract：The adsorption behavior including adsorption kinetics and adsorption isotherms of polycarboxylate（PC） superplascticizer onto cement particle surfaces in true water/cement conditions was investigated to offer guidance for selecting PC with specific dispersing speed. The results show that the adsorption kinetics of PC on the cement particle surfaces follow pseudo-second order model. Moreover，the adsorption rate k1 is decreasing and the saturated adsorption amount（Qs） is increasing with the increasing
dosage for the same PC. The adsorption isotherm of PC on the surface of cement particles or their hydrated products is a typical Langmuir monolayer adsorption. Furthermore, just changing the parameters such as side chains density，molecular weight，play a minor role in Langmuir equilibrium constant——k2 for given monomer species.
    Key words：polycarboxylate superplascticizer，adsorption kinetics，pseudo-second order model，adsorption isotherms，Langmuir equation