衣康酸酯类聚羧酸系减水剂的制备及表征

Synthesis and Characterization of a Polycarboxylate Type Superplasticizer Containing Itaconic Ester

以衣康酸聚乙二醇酯大分子单体(IAPEG)、丙烯酸(AA)、马来酸酐(MA)和甲基丙烯磺酸钠(MAS)为原料,过硫酸铵为引发剂,经水溶液聚合制备了一种聚羧酸系减水剂(PC)。通过红外光谱对共聚物的结构进行了表征,采用凝胶渗透色谱仪对共聚物的相对分子质量及其分布进行了测定,讨论了聚合条件对减水剂性能的影响,得到最佳反应条件为:n(IAPEG)∶n(MA)∶n(AA)∶n(MAS)=1.5∶4.0∶6.0∶3.0,引发剂用量为单体总质量的10%,反应温度80℃,反应时间5 h。在该条件下合成的减水剂可以降低溶液的表面张力,促进水泥颗粒的分散,使水泥浆体具有较好的流动度。添加减水剂混凝土的减水率为39.2%,7 d抗压强度比(添加减水剂混凝土抗压强度/基准混凝土抗压强度)为191.4%,28 d抗压强度比为154.7%。

A polycarboxylate type superplasticizer(PC)was synthesized by water solution polymerization of itaconic acid polyethylene glycol ester(IAPEG),acrylic acid(AA),maleic anhydride(MA)and sodium methylacryl sulfonate(MAS)using ammonium persulfate as initiator.The copolymer was characterized by FTIR.Its molecular weight and molecular weight distribution were characterized by GPC.The influences of reaction conditions on the properties of the polycarboxylate type superplasticizer were discussed.The results showed that the optimal reaction conditions were as follows:n(IAPEG)∶n(MA)∶n(AA)∶n(MAS)=1.5∶4.0∶6.0∶3.0,initiator dosage being 10%of the mass of all monomers,reaction temperature80℃,reaction time 5 h.Under the optimum conditions,adding the synthesized polycarboxylate type superplasticizer could reduce the surface tension of the solution,promote the dispersion of cement particles and make the fluidity of cement paste better.The water reducing ratio of PC in concrete was 39.2%.The compressive strength ratio(the compressive strength of concrete with water reducing agent/compressive strength of reference concrete)of the concrete could reach 191.4%at 7 d and 154.7%at 28 d,respectively.