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首页> 外文期刊>Journal of Applied Polymer Science >Working mechanism of post-acting polycarboxylate superplasticizers containing acrylate segments
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Working mechanism of post-acting polycarboxylate superplasticizers containing acrylate segments

机译：含丙烯酸酯段的作用后聚羧酸酯超塑料的工作机理

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Acrylate-containing polycarboxylate superplasticizers were synthesized by copolymerizing acrylic acid, a-methallyl-xmethoxy poly(ethylene glycol) ether, and acrylic esters [hydroxyethyl acrylate (HEA) or hydroxypropyl acrylate (HPA)]. Their dispersing effects and fluidity-retaining capabilities were evaluated by spread tests of cement pastes. The temperature sensitivity of the performance was especially focused upon. It was found by Fourier transform infrared spectroscopy and specific anionic charge density measurements that the ester groups in the acrylate-containing copolymers hydrolyze in alkaline conditions, and thus additional RACOO(-) groups are continuously produced. The gradual production of RACOO(-) leads to increasing charge density and hence increasing adsorption of the polymer on the cement surface. The hydrolysis of HEA units is slightly faster than of HPA units in the corresponding copolymers. By this mechanism, a post-acting, or delayed, dispersing effect is realized. Such post-acting polymers alone or formulated with normal polycarboxylate superplasticizer can be used achieve a long fluidity retention of fresh concrete, especially under elevated temperatures. (C) 2017 Wiley Periodicals, Inc.
机译：通过共聚丙烯酸，甲甲基 - Xmethoxy聚（乙二醇）醚和丙烯酸酯[丙烯酸丙烯酸酯（HEA）或羟丙基丙烯酸氢丙烯酸酯（HPA）]来合成含丙烯酸酯的多羧酸酯超塑料。它们的分散效果和流动性保持能力是通过水泥浆料的展开试验来评估的。性能的温度敏感性特别集中在一起。通过傅里叶变换红外光谱和特定的阴离子电荷密度测量结果发现，含丙烯酸酯的共聚物中的酯基团在碱性条件下水解，因此连续产生额外的RacOO（ - ）基团。 RacoO（ - ）的逐步生产导致电荷密度的增加，从而增加了聚合物对水泥表面的吸附。 Hea单元的水解略微快于相应共聚物中的HPA单元。通过这种机制，实现了后作用或延迟的分散效果。单独或配制用正常的多羧酸盐超塑料剂的这种后作用聚合物可用于实现新的混凝土的长流动性保持，特别是在高温下。 （c）2017 Wiley期刊，Inc。

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