马来酰亚胺系减水剂的制备与作用机理的研究

Synthesis of maleimide-structural superplasticizer and study of the action mechanism

以过硫酸铵(APS)为引发剂,马来酸酐(MAH)、自制N-聚乙二醇单甲醚-N’-氨基甲酰马来酰亚胺(MPNCM)和甲基丙烯磺酸钠(SMAS)为聚合单体,合成N-聚乙二醇单甲醚-N’-氨基甲酰马来酰亚胺-甲基丙烯磺酸钠-马来酸酐共聚物(SP)。通过FTIR谱图对SP结构进行表征。以净浆流动度为指标,考察了引发剂用量、反应温度、n(MAH)/n(SMAS)摩尔比和n(MPNCM)/n(SMAS)摩尔比对净浆流动度的影响,并以净浆流动度、Zeta电位和吸附量为指标,探讨了马来酰亚胺系减水剂的作用机理。实验结果表明,最佳反应条件为n(MPNCM):n(SMAS)为1.2,n(MAH):n(SMAS)为5.0,引发剂用量0.15%(质量分数,下同)和反应温度为60℃;其分散机理主要是由于减水剂分子定向吸附在水泥颗粒表面,水泥颗粒表面形成双电子层,并在静电排斥作用下使水泥颗粒分散。

Maleirnide-structural superplasticizer （SP） was prepared from maleic anhydride （ MAH）, sodium methylallyl sullonate（SMAS） and sell-made N-methoxypolyethylene glyeols-N＇-carbamoyl maleimide （MPNCM） with ammonium persulphate （APS） as initiator. The molecular structure of SP was characterized by FTIR. Effects of the degree of initiator, polymerization temperature, the monomer mole of n （MAH）/n（SMAS） and the monomer mole of n（ MPNCM）/n（SMAS） were investigated with initial fluidity as measurement index. The action mechanism was investigated with initial fluidity, Zeta potential and adsorption as measurement index. The result shows that n （ MPNCM ） ： n （SMAS） is 1.2, n （ MAH ） ： n （SMAS） is 5.0, the amount of initiator is 0.15 % （mass fraction, the same below） and the reaction temperature is 60 ℃. In addition, it was suggested that the mechanism of the SP was mainly owing to electric double layer from the oriented adsorption between the SP and the surface of cement particles,and the cement paste in the steric repulsive force was dispersed.