Preparation and performance of a lignosulfonate-AMPS-itaconic acid graft copolymer as retarder for modified phosphoaluminate cement

In this article, a new type of graft copolymer retarder as modified phosphoaluminate cement (MPC) has been discussed. Graft copolymerization of 2-acrylamido-2-methyl propane sulfonic acid (AMPS) and itaconic acid (IA) onto sodium lignosulfonate (LS) was performed using potassium persulfate as an initiator by free radical aqueous solution copolymerization. The optimal LS/AMPS/IA copolymer (OLSAI) was obtained under the optimum reaction conditions: mass ratio of LS/(AMPS + IA) = 1:1, temperature = 60 degrees C, mole ratio of AMPS/IA = 9:1, initiator concentration = 1%, pH value = 5. The synthesized copolymer OLSAI was characterized by FTIR analysis. The experimental results demonstrate that the OLSAI has excellent retarding ability, dispersing power, thermal-resistant and pressure-tolerant properties, and little negative impact on the compressive strength of MPC. The graft copolymer OLSAI is expected to be an excellent retarder for MPC. (C) 2014 Elsevier Ltd. All rights reserved.