Synthesis and properties of an AMPS-modified polyacrylic acid superplasticizer

Abstract

A 2-acrylamide-2-methyl propylene sodium sulfonic (AMPS)-modified polyacrylic acid superplasticizer was synthesized using aqueous solution polymerization with the major monomers including the self-made active macromers polyethylene glycol mono-methyl ether acrylate acrylic (MPEGAA), acrylic acid (AA), AMPS, and sodium methyl allyl sulfonate (SMAS). The ratios of the monomers were determined using an orthogonal experiment. This research focused on the effects of the dosages of different macromers, the polymerization conditions, and the length of MPEGAA side chains on the properties of the AMPS-modified polyacrylic acid superplasticizer. The best polymerization conditions of the AMPS-modified polyacrylic acid superplasticizer are when (n(MPEGAA):n(SMAS):n(AMPS):n(AA) equals 0.1:0.1:0.2:0.65, the molecular weight of monomethoxypolyethylene glycol is 1 200, the initiator ammonium persulfate accounts for 5% of the total mass of the polymerized monomers, the polymerization temperature is 80 °C, and the reaction time is 4 h. The AMPS-modified polyacrylic acid superplasticizer synthesized in the best conditions exhibited excellent dispersivity and dispersion retainability. When the dosage ratio was 0.24%, the initial fluidity was 400 mm and the fluidity had nearly no loss after 1 h.