端羟基双子季铵盐对聚羧酸盐减水剂抗泥性能的影响

以1,4-对二氯苄为连接基团，分别以三乙胺和N,N-二甲基乙醇胺为头基，合成了具有不同端基的双子季铵盐（分别标记为KNJ-1和KNJ-2）。将其作为抗泥剂与聚羧酸盐减水剂复配以改善粘土对减水剂的负面效应，探究端羟基的引入对抗泥效果的影响。通过FT-IR和1H NMR对其进行结构表征。净浆流动实验考察抗泥剂的对流动度的影响，并结合XRD、XPS和 Zeta电位分析其与蒙脱土的作用机理。实验结果表明：与KNJ-1相比，加入0.3‰KNJ-2使水泥净浆初始流动度提高了35mm, 2h后流动度提高了165mm,表现出更好的抗泥效果。XRD和 XPS结果表明KNJ-2在蒙脱土的表面和层间吸附均优于KNJ-1，Zeta电位结果显示KNJ-2的加入使表面电位从初始的-15.67mV上升到-0.15mV。表明羟基可通过氢键作用优先吸附在蒙脱土的表面和层间，占据大量活性位点，减少了对聚羧酸盐减水剂的吸附，保障减水剂的高效分散能力，从而达到对粘土抑制的效果。

Effect of terminal hydroxyl quaternary ammonium salt on clay re-sistance of polycarboxylate superplasticizer

Two kinds of Gemini quaternary ammonium salts were synthesized by using triethylamine and 1,4-p-dichlorobenzyl as the linking group and N,N-Dimethylethanolamine (or triethylamine ) as the head group (labeled as KNJ-1 and KNJ-2).which was compounded with polycarboxylate superplasticizers to improve the negative effect of the clay on the polycarboxylate superplasticizers, the effect of the terminal hydroxyl group on the clay effect was investigated. The structure was characterized by FT-IR and 1H NMR.The effect of anti-clay agent was evaluated by the fluidity of cement paste. The mechanism was reveled by X-ray photoelectron spectroscopy,X-ray diffraction and Zeta potential measurement. The re-sults show that the addition of KNJ-2 increased the initial fluidity by 25 mm, and the fluidity increased by 165 mm after 2 hours, showing a good anti-clay advantage. XRD and XPS results showed that KNJ-2 is superior to KNJ-1 in surface and interlayer adsorption of montmorillonite. And the Zeta potential of montmorillonite was increased from the initial -15.67mV to -0.15mV.This is ascribed to hydroxyl group which can generate hydrogen bond with the surface and interlayer of the montmorillonite, occupying a large number of active sites. polycarboxylate superplasticizers can be prevented from being absorbed in surface and interlayers of clay to ensure better dispersion performance ,presenting a marked anti-mud ef-fect.