含蔗糖侧链对聚羧酸减水剂抗泥性能的影响

Effect of sucrose side chain on the clay resistance of polycarboxylate superplasticizers

以马来酸酐与蔗糖酯化反应制得马来酸酐-蔗糖酯单体,并进一步与马来酸酐及异戊烯基聚氧乙烯醚水溶液自由基共聚合成侧链含蔗糖基团的减水剂。系统考察了马来酸酐、马来酸酐-蔗糖单体及异戊烯基聚氧乙烯醚三者比例对减水剂分散性能及抗蒙脱土性能的影响。结果表明:由于侧链引入了空间位阻较大的蔗糖结构,难以与蒙脱土形成插层吸附,使其更易吸附于水泥颗粒表面,从而对蒙脱土的忍耐性显著提高;混凝土试验显示,合成减水剂大大改善了混凝土的黏土忍耐性,同时对混凝土的后期抗压强度略有提升。

A novel polycarboxylate superplasticizer with sucrose as side chain was prepared through aqueous free radical polymerization of maleic anhydride,isopentenyl tenepolyoxyethylene ether and sucrose graft maleic anhydride,which was synthesized by esterification of maleic anhydride and sucrose.Effects of the molar ratio of maleic anhydride,sucrose graft maleic anhydride and isopentenyl polyoxyethylene ether on the dispersibility and montmorillonite tolerance of the superplasticizer were systematically studied.The results show that it is difficult to form intercalation adsorption with montmorillonite due to the introduction of sucrose structure with larger steric hindrance in the side chain,which leads to the tendency of adsorption on the surface of cement particles,thus greatly improving the tolerance of montmorillonite.Concrete tests show that synthetic superplasticizer greatly improve the clay endurance of concrete,and at the same time slightly increase the later compressive strength of concrete.