MPEGMAA/G-570/DEM/AMPS新型酯类聚羧酸系减水剂的制备

Preparation of MPEGMAA/G-570/DEM/AMPS Polyether-type Cement Water Reducing Agent

以甲基丙烯酸聚乙二醇单甲醚酯600(MPEGMAA600)、γ-甲基丙烯酰氧基丙基三甲氧基硅烷(G-570)、马来酸二乙酯(DEM)和2-丙烯酰胺-2-甲基丙磺酸(AMPS)为原料,过硫酸钾-硫酸亚铁为引发剂,合成了G-570/MPEGMAA/DEM/AMPS酯类聚羧酸系减水剂,其结构和组成经傅立叶变换红外光谱(FT-IR)和凝胶色谱(GPC)表征。通过正交实验确定最佳合成工艺为:MPEGMAA与DEM、AMPS和G-570的摩尔比为1.0∶1.0∶2.0∶0.4,过硫酸钾-硫酸亚铁总质量占聚合单体总质量的0.4%,于45℃聚合反应8 h,单体转化率为91.71%,水泥初始净浆流动度为225 mm。通过X-射线衍射(XRD)和热重(TG-DTG)分析对加入该减水剂的硬化水泥石微观结构进行了分析。结果表明:该减水剂链段中含有酯基、氨基、磺酸基、醚键、硅氧键等基团,平均相对分子质量分布集中,峰值大都集中在1.2~1.7万。同时,该减水剂可以延缓24 h内水泥水化。

MPEGMAA/G-570/DEM/AMPS polyether-type cement water reducing agent was synthe- sized using methylacrylic acid polyethylene glycol single methyl ether-600 ester （ MPEGMAA600 ）, 3- （trimethoxysilyl） propyl methacrylate （ G-570 ）, diethyl maleate （ DEM ） and 2-acrylamide-2-methyl propane sulfonic acid （AMPS） as raw materials, under the function of redox initiator in potassium per- sulfate/ferrous sulfate. The structures and compositions were characterized by fourier-transform infrared spectroscopy（FT-IR） and gel permeation chromatography（GPC）. The optimum conditions obtained by orthogonal experiment were as follows： mole ratio of MPEGMAA600/DEM/AMPS/G-570 was 1.0 ： 1.0 ： 2.0 ： 0.4, the amount of potassium persulfate/ferrous sulfate was 0.4% according to the mass of monomers, reaction at 45 ℃ for 8 h, the percentage of conversion was 91.71% and the initial fluidity was 225 mm. The water reducing agent chain segment contains ester base, amino sulfonic acid, sulfonic acid group, ether bond, silica base and other functional groups. The average relative molecular mass distribution and peak mostly focus on 12 000 - 17 000. The microstructure of mixing water reducing agent cement paste were analyzed by X-ray diffraction（XRD） and thermal gravity analysis （TG-DTG）. The results showed that the water reducing agent can delay the cement hydration within 24 h.