Influence of Side Chain Density of Polycarboxylate Superplasticizer on Hydration of Cement
Polyethylene glycol monomethyl ether acrylate macromer was synthesized by esterification using polyethylene glycol monomethyl ether ((-M)n=750)and acrylic acid as monomers. Polycarboxylate superplasticizer with different side chain density (-OC_2H_4-) was synthesized by copolymerization with macromer, sodium allylsulfonate and acrylic acid at different molar ratio in the initiator of ammonium persulfate. The results shown that the fluidity, dispersivity was increased with -OC_2H_4- increased, especially at n(-COOH)∶ n(-OC_2H_4-)=1∶ 1. The water reduction ratio was over 24 % and reached maximum value 28.5% as n(-COOH)∶ n(-OC_2H_4-)=1∶ 1. The strength of cement mortar was enhanced with -OC_2H_4- increased comparing with blank cement. It can also be proved by SEM and XRD analysis.