MAPEG-HEA-SMAS三元共聚物高效减水剂的制备与性能

以马来酸聚乙二醇单酯(MAPEG)、丙烯酸羟乙酯(HEA)、甲基丙烯磺酸钠(SMAS)为原料通过共聚反应制得MAPEG-HEA-SMAS三元共聚聚羧酸高效减水剂,考察了单体摩尔比、引发剂用量、反应温度等合成条件对减水剂性能的影响,并用IR对减水剂的分子结构进行表征,以GPC表征减水剂的相对分子质量(简称分子量,下同)及其分布,通过SEM观察了掺入减水剂的水泥石微观结构。结果显示,当n(MAPEG)∶n(HEA)∶n(SMAS)=1.0∶1.5∶1.0,聚合反应温度为88℃,聚合反应时间为7.5 h,引发剂用量为单体总质量的3.5%,PEG相对分子质量(简称分子量,下同)为1 000时,合成的减水剂综合性能良好。当其掺量为0.45%(质量分数)时,水泥净浆初始流动度达308 mm。GPC分析显示,减水剂平均分子量Mn=7 752,分散系数Mw/Mn=2.091;SEM分析结果显示,聚羧酸减水剂使水泥石大孔率降低,结构更密实。

Preparation and Performance of Polycarboxylate Terpolymer Superplasticizer MAPEG-HEA-SMAS

Polycarboxylate terpolymer superplasticizer MAPEG-HEA-SMAS was synthesized by copolymerization with esterification intermediate(MAPEG),hydroxyethyl acrylate(HEA) and sodium methallyl sulfonate(SMAS) as the main raw materials.The influence of molar ratio of monomer,dosage of initiator,reaction temperature and reaction time on the copolymerization was investigated.The structure was characterized by means of IR.The relative molecule mass and its distribution of the superplasticizer is measured by GPC,and the microstructure of cement is characterized by means of SEM.The results show that when the molar ratio of MAPEG to HEA to SMAS is 1.0∶ 1.5∶ 1.0,the polymerization reaction temperature is 88 ℃,the polymerization reaction time is 7.5 h,the dosage of initiator is 3.5% of total monomer mass and the relative molecule of PEG mass is 1 000,the superplasticizer would exhibit good performance.The original fluidity of cement grout can reach 308 mm with 0.45% mass content of this superplasticizer(mass fraction).GPC shows that the mean molecular weight Mn and polydispersity Mw/Mn of the superplasticizer are 7 752 and 2.091 respectively.SEM shows that the superplasticizer can reduce the amount of macropores of cement and that the crystals grow denser.