Polycarboxylate superplasticizers (PCEs) achieve dispersion mainly via steric hindrance from poly(ether) side chains. However, long side chains may cause structural collapse. This study mitigates this issue by introducing sulfonic acid terminations to the long side chains, synthesizing sulfonic-terminated polycarboxylates (PCEPS). Electrostatic repulsion between sulfonic and carboxyl groups on the main chain reduces the level of collapse, enhancing PCE dispersion in cement. PCEPS-4000 showed the strongest dispersion compared with conventional PCEs (PCEC). PCEPS-4000 formed an adsorption layer thickness (ALT) of 11.65 nm, showing a significant improvement over the 7.93 nm observed in the carboxyl-terminated long side chain polycarboxylate (PCETA). Stronger negative charge and lower complexation of sulfonic acid groups enhance the side chain extension. PCEPS also shows good clay tolerance and slump retention, proving its versatility as a concrete admixture.

中文翻译：

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磺酸封端长侧链聚羧酸减水剂的合成、性能评价及吸附-分散机理


聚羧酸减水剂 （PCE） 主要通过聚醚侧链的空间位阻实现分散。然而，长侧链可能会导致结构坍塌。本研究通过将磺酸末端引入长侧链，合成磺酸封端聚羧酸盐 （PCEPS） 来缓解这个问题。主链上磺酸基团和羧基之间的静电排斥降低了塌陷水平，增强了 PCE 在水泥中的分散性。与传统 PCE （PCEC） 相比，PCEPS-4000 显示出最强的分散性。PCEPS-4000 形成的吸附层厚度 （ALT） 为 11.65 nm，与在羧基封端的长侧链聚羧酸盐 （PCETA） 中观察到的 7.93 nm 相比有显著改善。更强的负电荷和较低的磺酸基团络合增强了侧链延伸。PCEPS 还表现出良好的粘土耐受性和坍落度保持性，证明了其作为混凝土外加剂的多功能性。