淀粉基聚羧酸减水剂的合成及应用性能研究

Synthesis and application of a kind of starch based polycarboxylate water reducing agent

通过对淀粉进行预处理,在自由基反应合成减水剂时替代部分聚醚大单体合成一种淀粉基聚羧酸减水剂,通过控制变量法确定最佳合成条件:氧化剂选用浓硫酸,用量为1.5%,淀粉选用衍生物白糊精,改性淀粉对大单体的取代率为1%。通过净浆、砂浆和混凝土试配可知,此减水剂能使混凝土具有优异的流动性和可塑性,同时具有良好的抗泥效果,且对强度有积极影响,SEM分析显示,淀粉基聚羧酸减水剂提高了水泥的水化速率,降低了因水分蒸发引起的自收缩,提高了结构的密实度。

By pre-treatment of starch,a starch based polycarboxylate water reducing agent was synthesized by replacing some polyether macromers during the free radical reaction synthesis of water reducing agents.The optimal synthesis conditions were determined by controlling variables,such as using concentrated sulfuric acid as the oxidant at a dosage of 1.5%,using a derivative of white dextrin as the starch,and the substitution rate of modified starch for macromers was 1%.Through the trial mix of cement paste,mortar,and concrete,it is known that this water reducing agent can make concrete have excellent fluidity and plasticity,as well as good mud resistance,and has a positive impact on strength.SEM analysis shows that starch based polycarboxylate water reducing agent increase the hydration rate of cement,reduce self-shrinkage caused by water evaporation,and improve the compactness of the structure.