聚羧酸系减水剂的合成及应用性能

Synthesis and application properties of polycarboxylate superplasticizers

采用大单体与小单体共聚技术,以甲氧基聚乙二醇甲基丙烯酸酯(mPEG1000MA或mPEG2000MA)与丙烯酸等为原料,合成了一系列不同组成和结构的聚羧酸减水剂。测定其特性黏度以表征相对分子质量大小。采用示差扫描量热法(DSC)表征其结晶性能,间接描述减水剂分子的梳状结构特征。测定了减水剂对水泥净浆流动度(分散作用)及流动度的经时保持性(保塑作用)等应用性能。结果表明:聚羧酸减水剂的分子结构对其应用性能有很大影响。主链长度、侧链长度、侧链疏密等因素都在一定程度上影响其对水泥的分散作用及保塑性能。

A series of polycarboxylate superplasticizers with various compositions and molecular structures were synthesized using free-radical copolymerization of acrylic acid and methacrylate macromonomers such as mPEG1000MA or mPEG2000MA in aqueous solution.The characteristic viscosity of polycarboxylate superplasticizer was used to characterize the relative molecular mass.The crystallization behavior of the polyethylene oxide（PEO） side chain was investigated using differential scanning calorimetry（DSC） to analyze the comb-like molecular structure of the superplasticizers.The influences of molecular composition and structure on the performance of polycarboxylate superplasticizer were measured in cement pastes.The results show that the main chain length,the side-chain density,and the side-chain length all affect the cement paste flow ability and the flowing retention ability over time.