酯类小单体对聚羧酸减水剂缓释行为的影响

The Effect of Small Ester Monomers on the Slow-release Behavior of Polycarboxylate Superplasticizer

分别以丙烯酸羟乙酯(HEA)、丙烯酸羟丙酯(HPA)、衣康酸二甲酯(DEI)、富马酸二甲酯(DMF)作为功能小单体,丙烯酸和甲基烯丙基聚氧乙烯醚(HPEG)为主要原料,在氧化-还原体系下,成功制备了一系列缓释型聚羧酸减水剂(PCE)。采用红外光谱(FTIR)、核磁共振氢谱(^(1)H NMR)等对目标产物的结构进行了表征。根据水泥净浆的流动性对比结果,确定了合成的减水剂在不同时间所达到的最大流动度,考察了不同酯类单体对聚羧酸减水剂的缓释性及分散保持性能的影响,并测试了水泥浆体的Zeta电位、PCE的吸附行为。结果表明:DEI的缓释效果优于HEA和HPA,水泥浆流动度在2 h内从190 mm达到255 mm,大大延长了减水剂PCE在水泥表面的吸附时间和流动度保持时间,在实际应用中具有良好的参考意义和应用前景。

A series of slow-release polycarboxylate superplasticizer(PCE)were prepared under the oxidation-reduction system,using hydroxyethyl acrylate(HEA),hydroxypropyl acrylate(HPA),dimethyl itaconate(DEI)and dimethyl fumarate(DMF)as functional small monomers respectively and acrylic acid and methallyl Polyoxyethy-lene ether(HPEG)as the main raw material.The structure of the polymers was characterized with FTIR and ^(1)H NMR spectroscopy.The maximum fluidity reached by the synthetic superplasticizer at different intervals was determined according to the comparison of the fluidity of the cement paste,the effect of the different ester monomers on the slow release of the polycarboxylate superplasticizer was investigated,and the Zeta potential of the cement paste and the adsorption behavior of PCE were tested.The results showed that the slow-release effect of dimethyl itaconate was better than that of hydroxyethyl and hydroxypropyl ester,and the fluidity of the cement slurry was better than that of hydroxyethyl and hydroxypropyl esters.From 190 mm to 255 mm within 2 h,the adsorption time and fluidity retention time of PCE on the cement surface was greatly prolonged.The material has good application prospects for high fluidity and long-term maintenance of concrete configurations.