Preparation and performance analysis of polycarboxylate superplasticizer modified with fluorine-containing monomer and silicon dioxide nanoparticles

Abstract

With the development of technology, the performance requirements for building materials in the modern construction industry are increasing. Nanomaterials and polycarboxylate superplasticizers (PCE) have good applicability in this field. Therefore, we develop a composite material by incorporating a fluorocarbon surfactant (FS) as a shrinkage-reducing agent into the PCE and modifying it with silicon dioxide nanoparticles (nano-SiO2) (SiO2-FS-PCE). Moreover, we investigate the preparation, dispersity, flowability, rheological properties, adsorption performance, and microstructure of the SiO2-FS-PCE composite. We observe that introducing an appropriate concentration of fluorine-containing monomer can effectively reduce surface tension in the solution and inhibit the shrinkage of the slurry. The rheological properties of the SiO2-FS-PCE1 slurry decrease significantly with time. When the dosage of nano-SiO2 exceeds 20%, the silicon hydroxyl groups on the material’s surface tend to polymerize, which affects the adsorption and dispersion of the superplasticizer, thereby reducing its fluidity. As the dosage of nano-SiO2 increases, there is a trend of increasing friction of SiO2-FS-PCE, followed by a decrease. This change is closely related to changes in the adsorption and morphology of SiO2-FS-PCE, providing higher adsorption sites than other materials. In conclusion, these findings provide insights for a deeper understanding of the synthesis and properties of nanocomposite materials, thereby offering a theoretical basis for further optimization of their preparation and performance.