水溶液中共聚合成聚羧酸系高效减水剂及其性能

Synthesis and performance of polycarboxylate based superplasticizer by free radical copolymerization in aqueous solution

以活性大单体聚乙二醇单甲醚甲基丙烯酸酯(MPEGMA)、甲基丙烯酸、马来酸酐和烯丙基磺酸钠为原料,在水溶液中共聚合成聚羧酸系混凝土高效减水剂.考察了单体的摩尔配比、引发剂种类和用量以及甲氧基聚乙二醇(MPEG)分子量等合成条件对减水剂性能的影响.结果表明,最佳的减水剂合成条件为:马来酸酐、MPEGMA、甲基丙烯酸和烯丙基磺酸钠摩尔比为3∶4∶1∶2,引发剂过硫酸铵用量为单体总质量的2.0%,MPEG分子量为1 300.在上述条件下制备得到的聚羧酸减水剂具有良好的分散性和保塑性,掺入该减水剂0.3%(质量分数)的水泥净浆流动度可达到290mm.

Polycarboxylate based superplasticizer was synthesized with active macromonomer methoxy（polyethyleneglycol）methacrylate（MPEGMA）,maleic anhydride,methacrylic acid and sodium allylsulfonate by free radical copolymerization in aqueous solution.The influence of molar ratio of monomer,type and dosage of initiator and the molecular weight of methoxy polyethylene glycol（MPEG） on the copolymerization were investigated.The results show that the optimum reaction condition is as follows： the molar ratio of maleic anhydride to MPEGMA to methacrylic acid to sodium allylsulfonate is 3∶4∶1∶2,the dosage of ammonium persulfate is 2.0% of total monomers by mass,and the molecular weight of MPEG is 1300.The polycarboxylate based superplasticizerprepared under this condition would have good plasticizing and fluidity.The fluidity of cement paste can reach 290 mm with 0.3% percentage mass content of this polycarboxylate based superplasticizer.