一种聚羧酸系减水剂大单体MPEGMA及掺入水泥的研究

Development of Macromer MPEGMA for a Polycarboxylate Superplasticizer and Mixes the Cement

采用油浴法,以甲基丙烯酸、聚乙二醇单甲醚为主要原料,以甲苯为带水剂、对甲苯磺酸为催化剂,对苯二酚为阻聚剂,通过酯化反应合成出甲基丙烯酸聚乙二醇单酯活性大单体。确定出最佳反应条件为:原料酸醇摩尔比为3∶1,催化剂对甲基苯磺酸的用量为3%(以聚乙二醇单甲醚的质量计),阻聚剂对苯二酚的用量为0.5%(以甲基丙烯酸的质量计),温度为115℃,反应时间为8 h,合成出活性大单体的酯化率可高达98%。由最佳酯化工艺制得的大单体为原料制备的聚羧酸系减水剂,具有良好的分散性和保塑性,掺该减水剂的0.5%,水泥净浆的初始流动度高达301 mm,静置120 min后,其流动度仍为295 mm。

Methacrylate polyglycol monoester was synthesized by condensation of MPEG and methacrylic acid with toluene as the water absorbent,toluene-4-sulfonic acid as the catalyst and hydroquinone as the inhibitor by the oil bath method.The optimal condition of esterification was studied by the design that the molar rate of acrylic acid to MPEG was 3∶1,the reaction temperature was 115 ℃,the reaction time was 8 h,the amount of catalyst was 3 % according to the mass of MPEG,the amount of inhibitor was 0.5 % according to the mass of MAA,the rate of esterification up to 98 %.And the polycarboxylate based superplasticizer prepared by the macromer under optimal condition had good plasticizing and fluidity-retaining ability,the initial fluidity of cement paste reaches 301 mm,and the fluidity was 295 mm after 2 min.