Maleic acid dipolyethylene glyeol mono methyl ether acetate (DMPEGMA) was synthesized by direct esterifieation without solvent with maleic anhydride (MAH) and polyethylene glyeol single methyl ether (MPEG) as raw materials in the presence of p-toluene sulfonic acid as catalyst and 4A molecular sieve as dehydrator. The influence of molar ratio of monomer, amount of catalyst, reaction temperature and reaction time on esterifieation rate were investigated. The results showed that the optimum reaction condition is as follows:the molar ratio of MPEG to MAH is 2.1:1.0,mass fraction of catalyst is 5% to the total MAH and MPEG,reaction temperature is 130 ℃ and the reaction time is 8 h. Under this condition, the esterifieation rate could reach 97.2%. The polycarboxylate superplasticizer prepared under this condition would have good plasticizing and fluidity. The fluidity of cement paste can reach 300 mm with 0.3% percentage mass content of the polycarboxylate superplasticizer and water-cement ratio (WIC) of 0.29.%在无溶剂存在下,以对甲苯磺酸为催化剂,4A分子筛作脱水剂,以马来酸酐(MAH)和聚乙二醇单甲醚(MPEG)为原料合成了马来酸双聚乙二醇单甲醚酯(DMPEGMA).考察了单体摩尔比、催化剂用量、反应温度及反应时间等条件对酯化率的影响.试验结果表明,当,n (MPEG)∶n (MAH) =2.1∶1.0,催化剂用量为聚乙二醇单甲醚和马来酸酐总质量的5％,反应温度为130℃,反应时间为8h时,酯化率可达到97.2％.以这种大单体合成的聚羧酸系减水剂具有良好的分散性和保塑性,当其掺量为0.3％,水灰比为0.29时,水泥净浆初始流动度达300 mm.
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