Study On Synthesis And Properties Of A Poly-carboxylic Superplastizer Of High Dispersion

A new poly-carboxylic superplasticizer was obtained by grafting functional groups of carboxyl, sulfonic, hydroxyl, and polyoxyethylene, which had excellent application properties of high water-reducing, good slump-loss resistant and high dispersion, and the relation between chemical structure and properties of poly-carboxylic superplasticizer was discussed.The esterification parts, the best experimental conditions and proportion to synthesis of macromer for poly-carboxylic superplasticizer were determined. Methacrylate polyglycol monoester (PA) was synthesized by different polymerization of polyethylene glycol (monomerthylether) and methacrylic acid with toluene-4-sulfonic acid as the catalyst and hydroquinone as the inhibitor, the most ideal preparation process and reaction conditions are found, the reaction rules are mastered, a series PA with different chains are gained. The preparation technology and proportion of synthesis of series of PA had better stability and repetition, which were found by many experiments.The radical polymerization parts, a new poly-carboxylic superplasticizer(PCS-1) was synthesized by series of PA, methacrylic acid and 2-Methyl-2-propene-1-sulfonic Acid Sodium Salt with the initiator of ammonium persulfate. The paper investigated the effect of dispersion properties of superplasticizer by the condition of synthesis of poly-carboxylic superplasticizer, such as reaction temperature, reaction time, dosage of initiator, manners of casting materials, concentration etc, the best preparation technology of the synthesis of poly-carboxylic superplasticizer was found by orthogonal test.The last, the properties of concrete with PCS-1 were tested, and the experiment comparing with other kinds of superplasticizer. the water reducing mechanism of poly-carboxylic superplasticizer was discussed by studying of properties such as fluidity of cement, surface tension, Zeta potential, adsorption and so on. The experimental results showed that the concrete with PCS-1 has the advantages of high water-reducing, excellent fluidity of cement, good slump-loss resistant, high strength enhancement, good dispersion and its maintain, and PCS-1 was applicable for various ordinary Portland cement, and had better compatibility with cements. The water-reducing ratio up to 40%, the fluidity of cement reach to 304 mm, good slump-loss resistant, when water-cement ratio was 0.29 and PCS-1 of cement mixture was 0.45%. The experimental results showed that PCS-1 was a kind of poly-carboxylic superplasticizer with high dispersion.