Title: Synthesis, Characterization, and Dispersing Performance of a Novel Cycloaliphatic Superplasticizer

Author(s): Lei Lei, Johanna de Reese, and Johann Plank

Publication: Symposium Paper

Volume: 288

Issue:

Appears on pages(s): 1-17

Keywords: Cyclohexanone formaldehyde sulfite polycondensate (CFS); dispersion, adsorption, clay

DOI: 10.14359/51684217

Date: 9/14/2012

Abstract:
A novel superplasticizer made from cyclohexanone, formaldehyde and pyrosul¬fite utilizing a polycondensation reaction is presented. The new CFS polymer possesses a molecular weight of ~57 kDa and medium anionic charge density of ~1100 μeq/g. It disperses cements of diverse compositions (CEM I, CEM II, CEM III) effectively and does not retard cement hydration. In the presence of clay (montmorillonite), its dispersing perfor¬mance is only slightly affected whereas that of a commercial polycarboxylate is severely perturbed. The reason behind is low adsorption of CFS on clay (~40 mg/g clay) while PCE sorbs in large quantity (~290 mg/g clay) and thus is deprived of cement. Adsorption and zeta potential measurements show that anionic CFS works by occupying positively charged surface sites on cement and achieves its dispersion effectiveness by instigating electrostatic repulsion between the cement particles.