淀粉基高效减水剂的制备与性能研究

Preparation of starch based water-reducing superplasticizer and its performance

以玉米淀粉为原料,N,N-二甲基甲酰胺(DMF)为分散剂,氨基磺酸为磺化剂,合成淀粉磺酸酯减水剂。采用IR,Ds和SEM来表征减水剂分子结构,并对其用作水泥减水剂进行性能测试。主要讨论了淀粉,分散剂和磺化剂的配比、反应温度、反应时间等因素对磺化反应的影响。得到最佳工艺参数为:糊精∶DMF∶氨基磺酸质量比为1∶2∶0.6,反应温度95℃,反应时间2 h。结果表明,淀粉基减水剂的分子中有羟基和磺酸基两种阴离子作用基团,磺酸基取代度为0.37,取代效果非常好。而且当减水剂掺量为水泥量的0.8%时,减水剂的减水率可达34.6%,符合减水剂的国家标准。

Taking comstarch as raw material,N,N-dimethylformamide as dispersing agent and sulfamic acid as sulfonating agent,starch sulfonate water-reducer is synthesized.The molecular structure of the water-reducer is demonstrate by means of IR,degree of substitution（DS） and SEM,and application performance of the water reducer on cement is tested.The influences of the starch proportioning,dispersing agent and sulfonating agent,reaction temperature and reaction time on sulfonation reaction are discussed.The optimum synthesis conditions are as follows∶ proportion of limit-dextrin,N,N-dimethylformamide and sulfamic acid is 1∶2∶0.6,the reaction temperature 95 ℃,reaction duration 2 h.Experimental results show that there are two anionic groups in the molecular structure of water reducer,which are hydroxy and sulphonic groups.The substitution degree of the sulphonic group is 0.37 that means good substitution effect.When the proportion of the water-reducer in cement is 0.8%,the water reducing ratio can reach 34.6%,which meets the national GB requirements.