The Synthesis And Performance Research On Poly-carboxylic Series Of Superplasticizer

Poly-carboxylic acid series superplasticier which was recognized inside and outside was a new and green-environment type water reducer, with a lot of characteristics such as low dosage, high-efficiency water-reducing ratio, strong dispersing retention property, low slump loss and wide adaptability to cement, it has favorable foreground for researching and applying.According to the chemical structure and effective mechanism of high-efficiency water-reducing agent, a new kind poly-carboxylic acid series superplasticier PC-C with comb like molecular which contained"carboxylic groups—polyoxyethylene side chain groups—sulphonic groups"was synthesized, the synthesized product's performance was tested. The water reducer was synthesized by two step reaction: (1) Esterification, a intermediate macromonomer(PEA) was made through the reaction of crylic acid and methyl polyethylene glycol-1000 under the effect of catalyzer; (2) Polymerization, poly-carboxylic acid series superplasticier was made from ethylene sulphonic sodium(SVS), crylic acid(AA) and intermediate macromonomer(PEA) by using ammonium persulfate as initiator.Furthermore, the experiment conditions and mixing proportion of intermediate macromonomer(PEA) were found by esterified reaction: in the condition of decompressing distillation, the dosage of P-toluene sulfonic acid used as catalyzer was 5% of methyl polyethylene glycol-1000's weight, and hydroquinone used as antipolymerizer was 0.5% of crylic acid's weight. The reaction temperature was about 100℃, the mol ratio of crylic acid and methyl polyethylene glycol-1000 was 3:1; The influence for mol ratio of crylic acid(AA), ethylene sulphonic sodium(SVS), intermediate macromonomer(PEA) and the dosage of initiator to the performance of poly-carboxylic acid series superplasticier was found by orthogonal experiments. The optimal mixing proportion for synthesizing the superplasticizer was SVS:AA:PEA=1.5:5:3, the dosage of initiator was 3% of gross weight of monomer. It proved that the superplasticizer was co-polymerized by unsaturated monomer with carboxylic groups, sulphonic groups and polyoxyethylene groups as side chain through infrared spectral analysis for the favorable product of poly-carboxylic acid series superplasticier.The superplasticizer PC-C prepared by ourselves was carried out performance testing...