聚羧酸系水泥减水剂的合成及性能

以丙烯酸甲酯(MA)、甲基丙烯磺酸钠(SMS)、甲基丙烯酸(MMa)、聚乙二醇单甲醚丙烯酸酯(P23MM)为原料,过硫酸铵(APS)为引发剂,进行水溶液自由基共聚,合成聚羧酸系水泥减水剂。以初始净浆流动度为考察指标,通过正交和单因素实验,确定合成聚羧酸系水泥减水剂的最佳工艺条件:APS用量为0.9%,n(P23MM)∶n(SMS)∶n(MA)∶n(MM a)=20∶8∶15∶47,反应温度80℃,反应时间8 h。合成的聚羧酸系水泥减水剂在低掺量(0.6%)、低水灰比(W/C=0.3)时,初始净浆流动度可达253 mm,2 h后净浆流动度仍有248 mm;减水剂水溶液(1%)的表面张力为53.88 mN/m,最优化条件下合成的减水剂水溶液为假塑性流体。

Synthesis and properties of the polycarboxylic cement water-reducing agent

Polycarboxylic water-reducing agent was synthesized with methyl acrylate,methylacrylamide sodium,methacrylate and polyethylene glycol monomethyl ether methylacrylate.Ammonium persulfate as the initiator was used for the radical aqueous solution polymerization.The formulation of the water-reducing agent APS,0.9%;n(P23MM) ∶n(SMS) ∶n(MA) ∶n(MMa) =20 ∶8 ∶15 ∶47] and optimized reaction conditions(RT=80 ℃,RH=8 h)were obtained via orthogonal test and single factor experiment.The initial fluidity of the cement paste containing the prepared water-reducing agent mix amount 0.6%,w(water):w(cement)=0.3] was 253 mm and remained 248 mm after 2 h.The surface tension of the product solution(1%)was 53.88 mN/m.The water-reducing agent produced on optimum conditions is pseudo plastic.