Effects of Chemical Structure on Adsorption of Polycarboxylate Superplasticizers on Cement Particles
Superplasticizers with various of length of side chains, density of the carboxylic (-COO-) and sulfonic groups (-SO3-) have been synthesized based on different monomers and ratios. The effects of these structural factors on the properties of cement pastes were investigated though measurements of paste fluidity, adsorption amount and Zeta potential (ζ-potential). The results indicated that the higher density of -COO- and -SO3- and the longer of polyoxyethylene (PEO) side chains contributed to the dispersion and adsorption amount of cement pastes in the presence of the same dosage of polycarbosylate superplasticizer. The results indicate that -COO- and -SO3- mainly provide electrostatic repulsion effects and PEO side chains contribute to the steric hindrance repulsion during the process of hydration of cement.
Linli Xu, Wenya Tian and Elwin Mao
S. H. Lv et al., "Effects of Chemical Structure on Adsorption of Polycarboxylate Superplasticizers on Cement Particles", Applied Mechanics and Materials, Vols. 80-81, pp. 185-189, 2011