新型酰胺结构聚羧酸高性能减水剂的制备与表征

Preparation and Characterization of New Type Amide-structural Polycarboxylate Superplasticizer

以聚丙烯酸(PAA)与端氨基甲氧基聚乙二醇(NPEG)为主要反应原料,合成了PAA-NPEG新型酰胺结构聚羧酸减水剂。通过红外光谱、核磁氢谱和分子量测试表征了减水剂产物分子结构和分子量特性,证明了酰胺化反应的高转化率和酰胺结构的存在。测定了酰胺结构减水剂的表面张力、水泥水化热及各项混凝土应用性能,并在此基础上分析了酰胺结构减水剂的作用机理。结果表明:酸胺的摩尔比为4:1时,溶液表面张力值和水泥水化峰位放热量最低;与掺有普通减水剂相比,掺有酰胺减水剂的混凝土含气量及保持能力、抗冻性能更优,且其它性能相近;酰胺结构的引入有利于提高其应用性能。

An amide-structural polycarboxylate superplasticizer was synthesized with polycarboxylic acid （PAA） and amino-methoxy polyethylene glycol （NPEG）. The molecular structure of superplasticizer was characterized by Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance, and molecular mass and distribution analysis, respectively. The high conversion of amidation reaction and the existence of amide structure were determined. The surface tension, hydration heat of cement, and application performance in concrete were measured, and the corresponding mechanism was analyzed. The results show that the lowest surface tension and hydration heat at a peak position is in the mole ratio of PAA to NPEG as 4：1. The air content and the retention and frost resistance of concrete for amide superplasticizer are more superior than those for common superplasticizer. The introduction of amide structure can improve its application performance.