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投料方式对聚羧酸减水剂分子质量及性能的影响
作者：李申桐，杨勇，周栋梁，王金勇，刘欢，陈露
（高性能土木工程材料国家重点实验室，江苏苏博特新材料股份有限公司，江苏 南京 211103）
摘要：通过GPC分析表明，聚羧酸减水剂在聚合过程中的不同反应阶段合成产物的分子质量变化很大。研究了引发剂次硫酸氢钠甲醛（SFS）、链转移剂巯基丙酸、单体丙烯酸等在前后期的投料比例对反应产物分子质量的影响，确定了调控过程分子质量变化的方法。试验结果表明：将投料方式调整为前一半滴加时间内，丙烯酸、SFS和巯基丙酸的投料比例分别为70%、60%和65%时，可使合成减水剂的分子质量在聚合过程中基本保持恒定；按该投料方式合成的聚羧酸减水剂对净浆和混凝土的分散性能明显提高。
关键词：聚羧酸减水剂；合成；分子质量；投料比例；性能
中图分类号：TU528.042+.2 文献标识码：A 文章编号：1001-702X（2021）02-0013-05
Effect of the feeding mode on the molecular weight and performance of the polycarboxylate superplasticizer
LI Shentong，YANG Yong，ZHOU Dongliang，WANG Jinyong，LIU Huan，CHEN Lu
（State Key Laboratory of High Performance Civil Engineering Materials，
Jiangsu Sobute New Materials Co. Ltd.，Nanjing 211103，China）
Abstract：The molecular weight of polycarboxylate superplasticizer was monitored by GPC throughout the polymerization process，and it was confirmed that the molecular weight varies significantly with the polymerization stages. The influence of the feed ratio of the initiator sodium sulfoxylate formaldehyde（SFS），chain transfer agent 3-mercaptopropionic acid，monomer acrylic acid，etc.on the molecular mass of the reaction product was studied，and the method of regulating the molecular mass change of the process was determined. The test results show that when the feeding proportion of acrylic acid，SFS and 3-mercaptopropionic acid were 70%，60% and 65% in the first half drop-adding time，the molecular weight of the synthetic superplasticizer can be kept basically constant during the polymerization process. The polycarboxylate superplasticizer synthesized according to this feeding method obviously improves the dispersion performance of cement paste and concrete.
Key words：polycarboxylate superplasticizer，synthesis，molecular weight，feeding proportion，performance