聚羧酸减水剂的分子结构对水泥水化过程的影响  

Effect of Molecular Structure of Polycarboxylate Water Reducers on Hydration of Cement

作　　者：李顺[1,2] 余其俊[1] 韦江雄[3] 

机构地区：[1]华南理工大学材料科学与工程学院,特种功能材料教育部重点实验室,广州510640 [2]中交四航工程研究院有限公司,中交集团建筑材料重点实验室,广州510230 [3]华南理工大学化学与化工学院,广州510640

出　　处：《硅酸盐学报》2012年第4期613-619,共7页Journal of The Chinese Ceramic Society

基　　金：国家"973"计划(2009CB623104);四川省非金属复合与功能材料重点实验室开放基金(10zxfk01);中央高校基本科研业务费专项资金(D211060w)资助项目

摘　　要：在水溶液体系下合成了一系列不同分子结构的聚羧酸减水剂,利用凝胶渗透色谱对其分子结构进行表征,探讨了分子结构对聚羧酸减水剂的分散性及其分散保持性的影响,并采用"水化热法"和"电阻率法"分析了聚羧酸减水剂的分子结构对水泥水化过程的影响。结果表明:聚氧化乙烯(polyethylene oxide,PEO)侧链较短时,聚羧酸减水剂表现出较高的分散保持性;PEO侧链接枝密度为1:3时,聚羧酸减水剂同时表现出较高的分散性及分散保持性,同时与减水剂的分子量分布密切相关;聚羧酸减水剂使水泥水化的诱导前期缩短,但诱导期延长,表现出一定的缓凝作用;PEO侧链较短、PEO侧链接枝密度适中的聚羧酸减水剂表现出较强的缓凝作用,与其在水泥颗粒表面的吸附行为有关;随分子量减小,这种缓凝作用略有加强;聚羧酸减水剂使电阻率曲线上对应的离子溶解平衡期延长,当PEO侧链较短、PEO侧链接枝密度适中时,聚羧酸减水剂对溶解平衡期的延长作用更明显,这与分子结构对水化热曲线上诱导期的延长规律类似。A series of polycarboxylate water reducers（PCs） with different molecular structures were synthesized in aqueous system.The molecular structure of PCs was characterized by a gel permeation chromatography.The effect of molecular structure on the dis-persibility and dispersion stability of PCs was discussed.The effect of molecular structure of PCs on the hydration of cement was also analyzed via the methods of hydration heat and electrical resistivity.The results show that the PCs with a shorter polyethylene oxide（PEO） side chain exhibit a higher dispersion stability.The PCs showed the higher dispersibility and dispersion stability at the same time when the density of PEO side chain was 1：3,which was correlated to the molecular mass distribution of PCs.The presence of PCs short-ened the earlier induction period and prolonged the induction period of hydration of cement,showing that the PCs had a retarding effect on the hydration of cement.This effect was strengthened for the PCs with a shorter PEO side chain and a moderate density of PEO side chain,which was related to the adsorption behavior of PCs.In this case,the retarding effect was also slightly strengthened with the de-creased molecular mass.Similarly,the presence of PCs prolonged the ion solution balance period of hydration in the curve of electrical resistivity,and this lengthening effect was more obvious for the PCs with a shorter PEO side chain and a moderate density of PEO side chain,which was similar to the effect of molecular structure on the induction period of hydration in the curve of heat evolution.

关 键 词：聚羧酸减水剂 分子结构 水泥 水化 电阻率 

分 类 号：TQ172[化学工程—水泥工业]