Synthesis and properties of amphoteric superplasticizer

A series of amphoteric polycarboxylic acid-based superplasticizers (APCs) was synthesized with different side chain lengths n EO from seven to 56 and characterized by FTIR spectra. The dispersing effectiveness of the APCs was assessed by the flow of paste. The amount of superplasticizers adsorbed on the cement significantly decreases with increasing side chain length n Eo- The properties of an anionic polycarboxylic acid-based superplasticizer (PCE) were also tested to be compared with APCs. The adsorption amount of APCs was larger than that of an anionic polycarboxylic acid-based superplasticizer (PC). Zeta potential measurements using the electroacoustic method indicate that the steric repulsion among the cement particles carrying adsorbed polymer molecules is the main force for dispersion. © 2011, American Concrete Institute. All rights reserved.