以马来酸酐(MA)与聚乙二醇(PEG)酯化生成马来酸聚乙二醇酯大分子单体(PEM),再与甲基丙烯磺酸钠(MAS)和丙烯酸(AA)在过硫酸铵的引发F共聚得到聚羧酸系减水剂。研究了MA与PEG的摩尔比,催化剂对甲苯磺酸(SMS)用量,反应温度、反应时间对酯化率的影响。利用正交试验优化了共聚反应原料摩尔比,引发剂用量,反应温度、反应时间等工艺参数。结果表明,增大MA与PEG摩尔比,提高催化剂用量,提高反应温度或延长反应时间都可以提高酯化率。最佳反应条件为:n(PEM):n(AA):n(MAS)=1:3:1,n(MA):n(PEG)=3:1,催化剂对甲苯磺酸用量为马来酸酐的3%,引发剂过硫酸铵用量为甲基丙烯磺酸钠、马来酸酐聚乙二醇酯和丙烯酸总质量的3%,反应温度为85℃,反应时间为5h。
Made maleic anhydride (MA) and polyethylene glycol (PEG) occur esterification reaction to produce maleic acid polyoxyethylene ester macromoleeular monomer (PEM). And polyearboxylate superplasticizer was prepared from the copolymerization of PEM, sodium methylallyl sulfonate and acrylic acid under ammonium persulfate initiator by the method of copolymerization. Studied influence of molar ratio of MA and PEG,amount of catalyst (SMS),reaction temperature and reaction time on the esterification rate. Used orthogonal test to optimize the above technological parameters,and the results show that increasing the molar ratio of MA and PEG, the amount of catalyst, the reaction temperature or the reaction time all can improve the esterification rate. The best reaction conditions are n (PEM) :n (AA) :n (MAS) =1:3:1, n (MA) :n (PEG) for 3:1, the content of catalyst is 3% of the mass of MA,the content of initiator is 3% of the total mass of sodium methyl acryl sulfonate,PEM and acrylic acid,the reaction temperature is 85 ℃,and the reaction time is 5h.