聚羧酸系减水剂的原位聚合工艺研究

Study of In-Situ Polymerization Process of Polycarboxylic Water-Reducing Agents

实验结果表明,以MPEG1000、丙烯酸(AA)、马来酸酐(MA)和烯丙基磺酸钠(丙钠)为原料,采用原位聚合工艺制备的聚羧酸系减水剂具有良好的性能。其较佳合成条件是:n(丙钠)∶n(MPEG)∶n(MA)∶n(AA)=1.0∶3.0∶4.5∶11.5,滴加时间和保温反应时间均为3.5h,滴加温度为80～85℃,保温反应温度为85～90℃,过硫酸铵用量为原料总质量的8.0%。当该减水剂的用量为水泥质量的0.325%时,水泥的净浆流动度达到265mm,减水率达到29%,坍落度高达200mm,90min后坍落度约损失10%,1d、3d、7d和28d的抗压强度增长比分别高达200%、175%、160%和160%。该合成方法具有生产工艺简单、合成成本低、产品性能好等优点。

Testing results revealed that polycarboxylic water-reducing agent synthesized by way of in-situ polymerization process from MPEG 1000, acrylic acid（AA）, maleic anhydride （MA） and sodium allylsulfonate as raw materials came out well with good performance. Its optimal conditions for synthesis were as follows： n（sodium allylsulfonate） ： n（MPEG1000） ： n（MA） ： n（AA）=1.0 ： 3.0 ： 4.5 ： 11.5, both of dripping time and reaction time = 3.5h; dripping temperature = 80-85℃, reaction temperature = 85-90℃; dosage of ammonium persulfate = 8.0% based on the weight of total reactants. When its dosage accounted for 0.325% based on cement mass, fluidity of cement paste attained to 265mm, water reduction to 29 %, slump to as high as 200mm, slump loss to 10% after 90 minutes, ld, 3d, 7d and 28d development ratio of compressive strength to as high as 200%,175%,160% and 160% respectively. This processfeatured simple production technology, low cost for synthesis and good performance of the products.