低敏感长效保坍型聚羧酸减水剂的合成及性能研究

Study on synthesis and properties of low sensitive and long-acting slump retaining polycarboxylic acid water reducer

采用乙二醇单乙烯基聚氧乙烯醚(EPEG)、丙烯酸(AA)、丙烯酸羟丙酯(HPA)和异构酯(PGE)进行四元共聚,合成了一种低敏感长效保坍型聚羧酸减水剂DJ-320,研究了合成因素对其分散性的影响,并评价其对含泥量和温度的敏感性。试验结果表明,DJ-320的最优合成工艺参数为:n(AA)∶n(HPA)∶n(EPEG)=2.2∶3.0∶1.0,PGE和巯基乙醇(ME)用量分别为单体总质量的0.9%和0.5%,A液滴加时间40 min。与市售高保坍型聚羧酸减水剂HS621相比,DJ-320具有更好的初始分散性和分散保持性,能保持净浆流动度3 h无损失,含泥敏感性和温度敏感性较低,混凝土和易性更优。

A low sensitive and long-acting slump retaining polycarboxylic acid water reducer DJ-320 was synthesized by quaternary copolymerization of EPEG,AA,HPA and PGE.The effects of synthetic factors on its dispersion and retention properties were investigated,and its sensitivity to mud content and temperature were evaluated.The results show that the optimal synthesis process of DJ-320 is n(AA)∶n(HPA)∶n(EPEG)=2.2∶3.0∶1.0,the dosage of PGE and ME is 0.9%and 0.5%of the mass of monomer respectively,and the dropping time of A is 40 min.Compared with high slump retaining type HS621,DJ-320 exhibits better dispersion and retention properties,can maintain the fluidity of net slurry for 3 h without loss,moreover DJ-320 has lower mud content sensitivity,temperature sensitivity and better concrete workability.