Synthesis, characterization and dispersing mechanism of aminosulfonate‐phenol‐formaldehyde superplasticizer for the cement particles

Abstract

In this study, a water‐soluble aminosulfonate‐phenol‐formaldehyde (ASPF) condensate was synthesized as superplasticizer (SP). The molecular structure of ASPF SP was characterized. The dispersing properties and the adsorption behavior of ASPF SP were measured and compared with sulfonated naphthalene‐formaldehyde (SNF) SP. ASPF SP has the more negative polar groups and the higher molecular weight than SNF SP. SNF SP adsorbs on the cement particle surface through “Flat train” adsorption configuration to form a single‐point adsorption. The higher adsorption amount and the thinner adsorption layer thickness. The dispersing ability of SNF SP for the cement particles is due to the electrostatic repulsion force between the cement particles. ASPF SP adsorbs on the cement particle surface through “loop and tail” adsorption configuration to form a multi‐point adsorption. The lower adsorption amount and the thicker adsorption layer thickness. Moreover, due to the more negative polar groups bonded to the molecule of ASPF SP, the cement particle surface with ASPF SP has a larger initial zeta potential, less zeta potential loss than that with SNF SP. The synergistic effect of the electrostatic repulsion force and the steric hindrance results in that ASPF SP has the better dispersing properties for the cement particles than SNF SP. POLYM. COMPOS., 39:2250–2258, 2018. © 2016 Society of Plastics Engineers