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Dispersing Efficacy of Tailored IPEG PCEs in AAS Binders: Elucidating the Impact of PCE Molecular Weight
Industrial & Engineering Chemistry Research ( IF 3.8 ) Pub Date : 2023-01-20 , DOI: 10.1021/acs.iecr.2c03820
Ran Li 1 , Wei-Chao Chen 1 , Lei Lei 1 , Johann Plank 1
Affiliation  

In this study, the impact of the molecular weight of isoprenol ether-based (IPEG) polycarboxylate superplasticizers on the dispersing effectiveness in sodium hydroxide-activated slag binder and slag composite cement was investigated. For this purpose, a series of IPEG polycarboxylate ether (PCE) superplasticizers possessing the same anionicity and the same side chain length but varying molecular weights (13,000–400,000 Da) were prepared. The synthesized PCE polymers were then subjected to application-related tests. It was found that their dispersing capacity in the AAS binder differed significantly and that IPEG PCE polymers possessing higher molecular weight generally were more effective. Surprisingly, it was also noticed that in the slag composite cement (90% slag, 10% OPC), generally, higher doses of the PCEs were required than in the OPC-free AAS binder system. Moreover, the working mechanism behind the enhanced dispersing ability of high Mw IPEG PCEs was studied via adsorption and adsorbed layer thickness (ALT) measurements. To determine the ALT of the adsorbed PCE polymers, phosphate-modified polystyrene nanoparticles were selected as a model substrate. Results from dynamic light scattering revealed that high Mw PCEs produce thicker adsorbed layers, which highly benefits the dispersing power of the PCE polymers stemming from enhanced steric hindrance. Finally, different models for the adsorbed conformations of those IPEG PCEs are proposed based on their individual molecular characteristics.

中文翻译:

定制 IPEG PCE 在 AAS 粘合剂中的分散功效:阐明 PCE 分子量的影响

在本研究中,研究了异戊二烯醚基 (IPEG) 聚羧酸减水剂的分子量对氢氧化钠活化矿渣粘合剂和矿渣复合水泥分散效果的影响。为此,制备了一系列具有相同阴离子性和相同侧链长度但不同分子量 (13,000–400,000 Da) 的 IPEG 聚羧酸醚 (PCE) 减水剂。然后对合成的 PCE 聚合物进行应用相关测试。发现它们在 AAS 粘合剂中的分散能力有显着差异,并且具有较高分子量的 IPEG PCE 聚合物通常更有效。令人惊讶的是,还注意到在矿渣复合水泥(90% 矿渣,10% OPC)中,通常,与不含 OPC 的 AAS 粘合剂系统相比,需要更高剂量的 PCE。此外,高分散能力增强背后的工作机制通过吸附和吸附层厚度 (ALT) 测量研究M w IPEG PCE。为了确定吸附的 PCE 聚合物的 ALT,选择磷酸盐改性聚苯乙烯纳米粒子作为模型基质。动态光散射的结果表明,高Mw PCE会产生更厚的吸附层,这极大地有利于 PCE 聚合物的分散能力,这源于增强的空间位阻。最后,基于这些 IPEG PCEs 各自的分子特征提出了不同的吸附构象模型。
更新日期:2023-01-20
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