酯化改性抗泥型聚羧酸减水剂的制备及性能研究

Preparation and Application of Esterification Modified Anti-mud PolycarboxylicAcid Water Reducer

聚羧酸减水剂对骨料含泥量较为敏感,这大大降低了其使用性能和效果,严重影响混凝土的工作性能。通过分子结构设计,将丁二酸酐(MAD)与异戊烯醇聚氧乙烯醚(TPEG)进行酯化反应合成抗泥单体M,然后将其与4-羟丁基乙烯基聚氧乙烯醚(GPEG)、丙烯酰胺(AM)、丙烯酸(AA)等共聚合成具有长支链酯基结构的抗泥型聚羧酸减水剂KNV,并通过红外光谱和核磁共振氢谱对其分子结构进行表征。结果表明:以n(MAD)∶n(TPEG)=3∶1进行酯化反应制备的抗泥单体合成的酯化改性抗泥型聚羧酸减水剂KNV具有较好的分散和保持性能;与市售抗泥型聚羧酸减水剂M12相比,随着泥土含量的增加,KNV的抗泥效果比M12好;不同种类水泥中,加入2.0%掺量的钠基蒙脱土,KNV表现出良好的水泥适应性和抗泥性能;同种水泥中,加入2.0%掺量的不同种类泥土,KNV的抗泥效果以及对泥土种类的适应性均比M12优异;将KNV应用到混凝土中,同样具有优异的抗泥能力,可降低减水剂的掺量和改善混凝土的和易性,提高混凝土的抗压强度。

Polycarboxylic acid superplasticizer is sensitive to aggregate mud content,which greatly reduces its performance and effect,and seriously affects the working performance of concrete.A kind of anti-mud polycarboxylic acid water reducer was synthesized by molecular structure design,anti-mud monomer M was synthesized by esterification of succinic anhydride(MAD)with isopentenol polyoxyethylene ether(TPEG),then copolymerized with 4-hydroxybutyl vinyl polyoxyethylene ether(GPEG),acrylamide(AM)and acrylic acid(AA)to form anti-mud polycarboxylic acid water reducer KNV with long branched ester group structure.The results show that the esterification modified anti-mud polycarboxylic acid water reducer KNV prepared by esterification of anti-mud monomer with n(MAD)∶n(TPEG)=3∶1 has good dispersion and retention properties.Compared with the commercially available anti-mud polycarboxylic acid water reducer M12,with the increase of soil content,the anti-mud effect of KNV is better than that of M12.The addition of 2.0%sodium bentonite to different type of cement shows good cement adaptability and mud resistance.When the same kind of cement was added with 2.0%different kinds of soil,the anti-mud effect and adaptability of KNV to different kinds of soil were better than those of M12.The application of KNV to concrete also has excellent mud resistance,which can reduce the amount of water reducer,improve the workability of concrete and increase the compressive strength of concrete.