TPEG-MAA-AM三元共聚高效减水剂的合成与性能研究

Research on the synthesis and performance of polycarboxylate terpolymer superplasticizer of TPEG-MAA-AM

以改性聚醚(TPEG)、甲基丙烯酸(MAA)和丙烯酰胺(AM)为主要原料,在引发剂和分子量调节剂作用下,在水溶液中共聚合成TPEG-MAA-AM三元共聚高效减水剂。考察了单体摩尔比、引发剂用量、反应温度和反应时间等合成条件对减水剂性能的影响规律。结果表明,最佳的减水剂合成条件为:n(TPEG)∶n(MAA)∶n(AM)=1∶1.3∶0.9,引发剂质量为单体总质量的5%,反应温度为75℃,反应时间为4h。在上述条件下制得的减水剂具有良好的分散性,掺入该减水剂0.2%(质量分数),水灰比为0.29时,水泥的净浆流动度可达到295mm。抗压强度测试表明,该种减水剂应用于混凝土多孔砖砌体中具有较好的力学性能。

A novel polycarboxylate superplasticizer of TPEG-MAA-AM was prepared by one-step method. The superplasticizer was directly polymerized using modified polyether（TPEG）, methylacrylic acid（MAA）and acrylamide（AM）as main raw mate- rials,ammonium persulfate as initiator, and 1-dodecanethiol as the molecular weight regulator in aqueous media The influence of molar ratio of monomer,dosage of initiator,reaction temperature and reaction time on the copolymerization were investigated. The results showed that the optimum reaction condition was as follows： the molar ratio of TPEG to MAA to AM was 1：1.3：0. 9, the dosage of ammonium persulfate was 5.0% of total monomers by mass, reactiun temperature was 75℃ ,reaction time was 4h. The polycarboxylate superplasticizer prepared under this condition would had good fluidity. The fluidity of cement paste can reach 295rnm with 0. 2% percentage mass content of this superplasticizer, and water-cement ratio（W/C）of 0. 29. The compressive strength tests showed that the superplasticizer had good mechanical properties in the masonry.