聚羧酸减水剂的合成及其分散性能

Synthesis and Dispersing Properties of Polycarboxylate Superplasticizer

以甲氧基聚乙二醇甲基丙烯酸酯(PMA45)、甲基丙烯酸(MAA)、甲基丙烯磺酸钠(MAS)为单体,以过硫酸铵(APS)为引发剂,采用水溶液自由基聚合法合成了聚羧酸高效减水剂(PC),分析了合成过程中不同单体摩尔比、相对分子质量(简称分子量,以下同)大小对其分散性能的影响。结果表明,单体和引发剂的用量同时影响聚羧酸减水剂分子量和分散性能;当n(MAS)∶n(MAA)∶n(PMA45)=0.5∶3.75∶1,APS用量为单体总质量的0.4%时,产品聚羧酸特性黏度为45.09 mL/g;当水灰质量比为0.25,聚羧酸减水剂掺量为水泥质量的0.2%时,净浆初始流动度达到最大269 mm,30 m in经时流动度为281 mm。

The polycarboxylate superplasticizer（PC） was synthesized with methoxy polyethylene glycol methacrylate,methacrylic acid,sodium methyl acryl sulfonate as monomers,using ammonium persulfate（APS） as initiator.The effect of the mole ratio of different monomers on the dispersing properties was analyzed.The results show that the dosage of monomers and initiator greatly influenced the molecular weight and dispersing properties of PC.When mole ratio of MAS,MAA and PMA45 was 0.5∶3.75∶1,dosage of APS was 0.4%,the product of PC had the best properties,with 45.09 mL/g of inherent viscosity;when used in cement system with water and cement mass ratio of 0.25 and dosage of 0.2%,the initial fluidity was 269 mm and 281 mm 30 min later.