A water-soluble acrylate/sulfonate copolymer. I. its synthesis and dispersing ability on cement

A new water-soluble methacrylate/2-acrylamido-2-methylpropane sulfonate copolymer (PMAMP) was synthesized and evaluated as a dispersion agent for cement particles. PMAMP was prepared from methacrylic acid and 2-acrylamido-2- methylpropane sulfonic acid (AMP). The structure of the prepared polymer was verified by its NMR and IR spectra. The dispersing properties of PMAMP were evaluated by a minislump test on cement pastes. The test results indicated that this copolymer could disperse the cement particles and improve the minislump of cement pastes. Compared with a commercial superplasticizer (sulfonated naphthalene formaldehyde condensates), PMAMP performed better in enhancing the fluidity of the cement pastes. The polymer with about 40-50% AMP and a weight-average molecular weight of about 5 × 104 was most effective in dispersing cement particles and promoting the fluidity of cement pastes. Nevertheless, PMAMP with a higher AMP content or a higher molecular weight appeared to cause less slump loss. This was related to the interaction of this admixture with the cement particles and its adsorption behavior onto the cement particles.