VPEG型聚羧酸减水剂的研制

Preparation of VPEG type polycarboxylic superplasticizer

采用4-羟丁基乙烯基聚氧乙烯醚(VPEG)为大单体,以双氧水(H2O2)/新型还原剂(F)为氧化还原体系,硫代乙醇酸为链转移剂合成了VPEG型聚羧酸减水剂PCE-1,探讨了合成温度及原材料配比对聚羧酸减水剂分散性的影响。结果表明,PCE-1的最佳制备工艺为:n(AA)∶n(VPEG-4000)=4.6∶1时,H2O2、新型还原剂、硫代乙醇酸用量分别为大单体VPEG质量的0.75%、0.2%、0.4%,合成温度15℃,滴加时间1.0 h。经测试验证,PCE-1的混凝土分散性和保坍性优于市售的VPEG型聚羧酸减水剂PCE-A和HPEG型聚羧酸减水剂PCE-B。

A VPEG type polycarboxylate superplasticizer PCE-1 was synthesized by using 4-hydroxybutyl vinyl polyoxyethylene ether(VPEG)as macromonomer,hydrogen peroxide(H2O2)/new reducing agent(F)as redox system and thioglycolic acid as chain transfer agent.The effects of synthesis temperature and raw material amount on the dispersion properties of polycarboxylate superplasticizer were discussed.The results showed that the optimum preparation process of PCE-1 was n(AA)∶n(VGEP-4000)=4.6∶1,the mass ratio of H2O2,new reducing agent and thioglycolic acid to VGEP macromonomer was 0.75%,0.2%and 0.4%,respectively,and the optimum synthesis temperature and dropping time were 15℃and 1.0 h,respectively.Tests show that PCE-1 has better concrete dispersion and slump retention than the VPEG polycarboxylate superplasticizer PCE-A and HPEG polycarboxylate superplasticizer PCE-B commercially available.