通过改变分子拓扑结构合成的新型聚羧酸超塑化剂的性能和工作机理。

Performances and working mechanism of a novel polycarboxylate superplasticizer synthesized through changing molecular topological structure.

机构信息

College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China.

出版信息

J Colloid Interface Sci. 2017 Oct 15;504:12-24. doi: 10.1016/j.jcis.2017.05.025. Epub 2017 May 10.

DOI:10.1016/j.jcis.2017.05.025

Abstract

A novel star-shaped polycarboxylate superplasticizer (SPCE) was synthesized through a simple two-step method. H Nuclear Magnetic Resonance (H NMR) and Infrared Spectroscopy (IR) measurements were used for structural characterization. SPCE and comb-shaped polycarboxylate superplasticizer (CPCE) with same molecular weights were designed and synthesized. The cement paste containing SPCE exhibited better fluidity, fluidity retention, water reduction, 25% lower saturated dosage of PCE, 10% longer setting time, lower hydration heat, more delayed hydration heat evolution and lower amount of hydration products at early ages. Furthermore, the adsorption behavior of SPCE and CPCE in cement pastes and the zeta potential were investigated, and then the working mechanism of SPCE was theoretically explained. It is interesting that changing topological structure from comb-shape to star-shape can achieve the optimization of dispersion effect, and further improve the working effectiveness. The aims of this study are to provide a new avenue to synthesize superplasticizer with novel structure achieving the chemical diversity of superplasticizer structure, and to verify the contribution of optimizing molecular shape. This new type of superplasticizer can be used as a rheology modifying agent in fresh cement-based materials.

摘要

一种新型星型聚羧酸超塑化剂（SPCE）通过简单的两步法合成。通过 H 核磁共振（H NMR）和红外光谱（IR）测量对其结构进行了表征。设计并合成了分子量相同的 SPCE 和梳型聚羧酸超塑化剂（CPCE）。含有 SPCE 的水泥浆具有更好的流动性、流动性保持性、减水性、PCE 饱和掺量降低 25%、凝结时间延长 10%、水化热降低、早期水化热释放延迟、水化产物减少。此外，研究了 SPCE 和 CPCE 在水泥浆中的吸附行为和动电位，并从理论上解释了 SPCE 的工作机理。有趣的是，改变拓扑结构从梳状到星状可以优化分散效果，并进一步提高工作效率。本研究旨在为合成具有新型结构的超塑化剂提供新途径，实现超塑化剂结构的化学多样性，并验证优化分子形状的贡献。这种新型超塑化剂可用作新鲜水泥基材料的流变改性剂。