Polycarboxylate superplasticizer modified by phosphate ester in side chain and its basic properties in gypsum plaster

In this study, 2-hydroxylethyl methacrylate phosphate was introduced as side chain to modify polycarboxylate superplasticizers (PCEs), and its performance in gypsum paste was systematically investigated. The results show that the introduction of phosphate ester can increase the water reduction ratio from 24% to 58%, and also extend the final setting time, showing excellent dispersing ability and retarding effect. The excellent dispersion was due to the stronger adsorption capacity of phosphate ester leading to high adsorption amount and high absolute value of zeta potential. In addition, the negative effect of the high adsorption amount on the crystal precipitation of calcium sulfate dihydrate is considered to be an important reason for retarding effect.