Rrsearch On Synthesis Optimization Test Of Polycarboxylate Superplasticizer

Polycarboxylate superplasticizer dosage is low, water reduction is high, slump retention ability is strong, it has significant enhancement effect on the concrete shrinkage, harmful substances content is low ,the technical performance characteristics give concrete excellent work, good strength development and excellent durability, it agrees the needs of modern concrete construction, and has comprehensive technical performance and environmental advantages. In this thesis the research and application actualities of high performance water reducers both in an outside china were introduced in detail, the synthetic methods and development trends of Polycarboxylic acid type high performance water-reducer was analyzed. Though the molecule design, beginning with the chemical structure and action mechanisms of high performance water-reducers, polycarboxylic acid type water-reducer which contain, hydroxy carboxyl, sulfonic, polyoxyethylene groups and so on with comb-like molecular structure was synthesized.Preparation of polyethylene glycol single methyl ether methacrylic acid ester (MPEGMAA) for synthesis of polycarboxylate superplasticizer, water-entraining in different ways , mulriple inhibitor , the amount of loaded catalysts impact esterification rate of polyethylene glycol single methyl ether methacrylic acid ester and light red macromer are successfully prepared and esterification rate is more than 99%,and its storage stability was studied preliminary. Polycarboxylic acid superplasticizer was synthesized at different initiator system by using the meacrylic acid (AR)and the meacrylic acid and the polyethylene glycol single methyl ether (MPEGMAA)(homemade). Relationship is discussed respectively between dosage of methyl propene sulfonate (SMAS), methacrylic acid (MAA) and initiator ammonium persulfate (PASM) and dispersion and dispersed retention of polycarboxylic acid superplasticizer. Based on the above results, Relationship is studied respectively between the dosage of ammonium persulfate - sodium bisulfite, ammonium persulfate - sodium bisulfite - ferrous salt, hydrogen peroxide - sodium bisulfite - ferrous salt and reaction temperature and dispersion and dispersed retention of polycarboxylic acid superplasticizer.Under the conditions of the redox system, temperature can be reduced to50- 60℃,with addition of 0.25-0.3% neat copolymer and water-cement ratio of 0.29, water reduction is more than 28%,paste fluidity is in the 250-260mm, fluidity retention rate is more than 95%,.Self-made macromer and PC superplasticizer are IR, the surface tension and adsorption of self-made PC solution, the mechanism of the water reducer is explored. And storage stability of self-made monomer is discussed, self-made PC superplasticizer compatibility with different varieties of cement and it makes concrete having good dispersion and dispersion retention, the setting time can be controlled and the bleeding rate and air-entraining effect is appropriate .