Study on the dispersion performance and mechanism of polycarboxylate superplasticizer by the long side‐chain dicarboxyl terminated

Abstract

The steric hindrance formed by polyether side chains is the key factor determining the dispersion performance of polycarboxylate superplasticizer (PCE).While with the increase of the side chain length, the coiled conformation of side chain will prevent the dispersion ability of PCE from being further improved. In this work, the methallyl polyoxyethylene ether (HPEG) was esterified with tricarballylic acid (TA) to obtain dicarboxyl terminated macromonomer, and further used to synthesize polycarboxylate (PCETA). The fluidity tests show that compared with ordinary PCE-B2400 with short side chain, the dispersion performance of PCETA-2400 was slightly improved. While for the PCEs with long side chain, the dispersion ability of PCETA-4000 was significantly improved than that of ordinary PCE-B4000. The adsorption layer thickness of PCETA-4000 adsorbed on the surface of SiO 2 sphere measured by dynamic light scattering is 7.93 nm, which is 1.3 times that of PCE-B4000. Due to electrostatic repulsion between the carboxylic groups, the stretching of long side-chain forms stronger steric hindrance and enhancing the dispersion of cement particles. In addition, PCETA also shows good slump retention and clay resistance properties, and it is an excellent multi-functional concrete admixture with great application potential.

Preparation of a Polycarboxylate Superplasticizer with Different Monomer Regulations and Its Effect on Fluidity, Rheology, and Strength of Cement

“…The water film having a good lubrication effect can effectively make the resistance in cement particles reduced and the fluidity of cement increased . Third, the VAPCE molecules are adsorbed on cement and the long side chain extends in the liquid phase of the cement slurry to form the three-dimensional, intersecting conformation . The adsorption layer overlaps when the cement particles move in parallel with each other.…”

“…43 Third, the VAPCE molecules are adsorbed on cement and the long side chain extends in the liquid phase of the cement slurry to form the threedimensional, intersecting conformation. 61 The adsorption layer overlaps when the cement particles move in parallel with each other. The repulsion between cement particles increased with the overlap range of the adsorption layer becoming greater, thereby improving the dispersion between cement particles.…”

Synthesis and properties of multi‐armed polycarboxylate superplasticizer modified by β‐cyclodextrin

“…According to the PCE reported in the previous literature, the increase rate of the compressive strength compared with blank cement samples is 58%. 31 Meanwhile, the mechanical strength of the cement sample gradually increased with the advancement of the hydration reaction process, so the reinforcement of compressive strength in the early stage is greater than that in the late stage, which can endow the cement products with more effective mechanical properties than those PCEs previously reported.…”

Synthesis of Polycarboxylate Superplasticizers via Photoinitiated Radical Polymerization

“…The molecular weight distribution of PCEs was tested by Agilent 1260 gel permeation chromatography and an Agilent 1260 differential detector. The hydrodynamic radius ( R h ) was tested by dynamic light scattering (DLS) with Zetasizer Ultra (Malvern Instruments, UK). , The carboxyl content of the PCE molecule was determined via titration using a Metrohm 809 Titrando …”

“…29,30 The carboxyl content of the PCE molecule was determined via titration using a Metrohm 809 Titrando. 31 2.4. Adsorption of the Synthesized Polymers.…”