氧化还原引发体系合成聚羧酸系高效减水剂

采用自制的聚乙二醇单甲醚1500甲基丙烯酸酯（MPEG1500-MAA）和甲基丙烯酸（MAA）试剂,在不同引发体系下合成聚羧酸系高效减水剂。分别探讨了甲基丙烯磺酸钠（SMAS）、甲基丙烯酸（MAA）以及引发剂过硫酸铵（PASM）的掺量与减水剂分散性和分散保持性的关系,研究了过硫酸铵—亚硫酸氢钠、过硫酸铵—亚硫酸氢钠—亚铁盐和过氧化氢—亚硫酸氢钠—亚铁盐三种氧化还原引发体系中各组分掺量、反应温度对减水剂分散性及分散保持性的影响,确定了在氧化还原引发体系条件下,减水剂反应温度可降低到60℃左右,所合成的减水剂为水泥折固掺量0.3%,水灰比为0.29时,其净浆流动度达250～260mm,30min流动度保持率大于95%。

Synthesis of poly-carboxylic acid superplasticizer via redox system

Polycarboxylic acid superplasticizer was synthesized at different initiator system by using the meacrylic acid（AR）and the meacrylic acid and the polyethylene glycol single methyl ether（1500）（MPEG1500-MAA）（homemade）.Relationship is discussed respectively between dosage of methyl propene sulfonate（SMAS）,methacrylic acid（MAA）and initiator ammonium persulfate（PASM）and dispersion and dispersed retention of polycarboxylic acid superplasticizer.Based on the above results,Relationship is studied respectively between the dosage of ammonium persulfate-sodium bisulfite,ammonium persulfate-sodium bisulfite-ferrous salt,hydrogen peroxidesodium bisulfite-ferrous salt and reaction temperature and dispersion and dispersed retention of polycarboxylic acid superplasticizer.Under the conditions of the redox system,temperature can be reduced to 60℃,with addition of 0.3%neat copolymer and water-cement ratio of 0.29,paste fluidity is in the 250-260mm,fluidity retention rate is more than95%.