聚醚型聚羧酸减水剂的合成和表征及对水泥的微观作用机制

Synthesis and Characterization of Polyether Type Polycarboxylate Superplasticizer and Its Microscopic Action Mechanism on Cement

本文以聚醚、丙烯酸、丙烯酸羟乙酯为原料,通过自由基聚合法合成了聚羧酸减水剂JS-PCE和BT-PCE。通过正交优化所得的JS-PCE合成条件为:聚合温度25℃,抗坏血酸-巯基丙酸混液、丙烯酸滴加时间分别为3 h、2.5 h,酸醚物质的量比为4.25∶1,引发剂加量为聚醚质量的1.10%。添加JS-PCE的水泥净浆流动度达230 mm,表现出较好的流动性。采用界面化学及电化学等方法探究了减水剂对水泥的微观作用机制,结果表明聚羧酸减水剂在水泥颗粒表面存在饱和吸附量,其与水泥颗粒存在强吸附作用,因此产生分散和减水作用。流变行为分析得出JS-PCE和BT-PCE的最佳折固掺量分别为0.3%、0.4%。

In this paper, polycarboxylate superplasticizers JS-PCE and BT-PCE were synthesized by free radical polymerization using polyether, acrylic acid and hydroxyethyl acrylate as raw materials. JS-PCE synthesis condition is optimized by orthogonal design as follows: the polymerization temperature is 25 ℃, the dripping time of ascorbic acid-mercaptopropionic acid mixture and acrylic acid is 3 h and 2.5 h, respectively, the ratio of acid to ether is 4.25 ∶1, and the initiator dosage is 1.10% of polyether total mass. The fluidity of the cement slurry with JS-PCE is up to 230 mm, which shows good fluidity. Interfacial chemistry and electrochemical methods were used to explore the micro-mechanism of superplasticizer on Xinjiang cement. The results show that the polycarboxylate superplasticizers have saturated adsorption capacity on the surface of cement particles, and there was strong adsorption between the polycarboxylate superplasticizers and cement particles, which contributed to dispersion and water reduction effect. The rheological behavior analysis shows that the optimal content of JS-PCE and BT-PCE is 0.3% and 0.4%, respectively.