聚羧酸系高效减水剂聚合反应动力学及其减水性能

采用分子设计原理,用甲氧基聚乙二醇丙烯酸酯(MPEGAA)、丙烯酸(AA)和马来酸酐(MAD)制备聚羧酸系高效混凝土减水剂,考察了单体总浓度、引发剂浓度、反应温度等因素对高效减水剂聚合反应速率的影响,建立了聚合反应动力学关系式,即r∝cI0.590 3c0M.808 9e-5 465/T。通过测定水泥净浆流动度,考察了高效混凝土减水剂的减水性能,确定了较理想的合成工艺条件,即单体物质的量比n(MPEGAA)∶n(AA)∶n(MAD)=1∶1.50∶0.36,引发剂占单体总质量的2.5%,反应温度为60℃,反应时间为6h。

Polymerization kinetics of polycarboxylate superplasticizer and its application properties

On the basis of the principle of molecular design,polycarboxylate superplasticizer was prepared by means of free radical polymerization with MPEGAA,AA and MAD as major monomers.The effects of total monomer concentration,initiator and reaction time on polymerization rate of the polycarboxylate superplasticizer were investigated,and the polymerization kinetic relation was obtained as r∝C0.590 3Ic0.808 9Me-5 465/T.The reducing performance of the superplasticizer was determined by means of measuring the fluidity of the cement paste,and the optimum reaction conditions were obtained,e.g.: the molar ratio of n(MPEGAA)∶n(AA)∶n(MAD) is 1∶1.50∶0.36,the amount of initiator is 2.5 wt% of monomer,the reaction temperature is 60 ℃,and the reaction time is 6 h.